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Data Service Options for Wideband Spread Spectrum Systems: Radio Link Protocol


PN-3676.2 (to be published as TIA/ EIA/ IS-707.2)

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Data Service Options for Wideband Spread Spectrum Systems: Radio Link Protocol
PN-3676.2 (to be published as TIA/ EIA/ IS-707.2)
Ballot Version
May 30, 1997
(Content Revision 11) 1
1 Page 2 3
Copyright 1997 TIA 2
2 Page 3 4
Ballot Version Proposed TIA/ EIA/ PN-3676.2
CONTENTS

i
1 Introduction .............................................................................................................. 1-1 1
1.1 General Description ............................................................................................. 1-1 2
1.2 Terms .................................................................................................................. 1-1 3
1.3 References ........................................................................................................... 1-2 4
2 General Requirements ............................................................................................... 2-1 5
2.1 Required Multiplex Option Support ...................................................................... 2-1 6
2.2 Interface to Multiplex Options .............................................................................. 2-1 7
2.2.1 Primary Traffic ............................................................................................... 2-1 8
2.2.2 Secondary Traffic ........................................................................................... 2-2 9
2.3 Traffic Channel Frame Priorities ........................................................................... 2-4 10
2.3.1 Non-Transparent RLP ..................................................................................... 2-4 11
2.3.2 Transparent RLP Frame Priorities................................................................... 2-5 12
3 RLP Procedures ......................................................................................................... 3-1 13
3.1 Non-Transparent RLP Procedures ........................................................................ 3-1 14
3.1.1 Initialization/ Reset Procedures ...................................................................... 3-1 15
3.1.1.1 Non-Encrypted Mode Initialization and Reset............................................ 3-1 16
3.1.1.2 Encrypted Mode RLP Initialization/ Reset .................................................. 3-2 17
3.1.1.2.1 Extended Data Frame Sequence Numbering........................................ 3-2 18
3.1.1.2.2 RLP Data Encryption Negotiation ........................................................ 3-3 19
3.1.1.2.2.1 Mobile Station Negotiation Procedures .......................................... 3-3 20
3.1.1.2.2.2 BS/ MSC Negotiation Procedures ................................................... 3-5 21
3.1.2 Data Transfer................................................................................................. 3-6 22
3.1.2.1 Non-Encrypted Data Transfer ................................................................... 3-6 23
3.1.2.2 Encrypted Data Transfer ........................................................................ 3-11 24
3.1.2.2.1 Encryption........................................................................................ 3-11 25
3.1.2.2.2 Decryption ........................................................................................ 3-11 26
3.1.3 Frame Validity Checks ................................................................................. 3-12 27
3.1.3.1 Primary Traffic........................................................................................ 3-12 28
3.1.3.2 Secondary Traffic ................................................................................... 3-13 29
3.1.4 Segmentation of Retransmitted Data Frames ................................................ 3-13 30
3.2 Transparent RLP Procedures .............................................................................. 3-15 31 3
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Proposed TIA/ EIA/ PN-3676.2 Ballot Version
CONTENTS

ii
3.2.1 Initialization.................................................................................................. 3-15 1
3.2.2 Data Transfer ............................................................................................... 3-15 2
3.2.3 Frame Validity Checks .................................................................................. 3-17 3
3.3 Traffic Channel Rate Control .............................................................................. 3-17 4
3.3.1 Service Option Negotiation Rate Control Procedures...................................... 3-17 5
3.3.2 Service Negotiation Rate Control Procedures ................................................. 3-18 6
3.3.2.1 Mobile Station Requirements................................................................... 3-18 7
3.3.2.2 BS/ MSC Requirements ........................................................................... 3-19 8
4 RLP Frame Formats.................................................................................................... 4-1 9
4.1 Traffic Channel Frames for Non-Transparent RLP ................................................. 4-1 10
4.2 Traffic Channel Frames for Transparent RLP ........................................................ 4-2 11
4.3 RLP Frame Formats .............................................................................................. 4-3 12
4.3.1 RLP Control Frames........................................................................................ 4-3 13
4.3.2 RLP Data Frames............................................................................................ 4-5 14
4.3.2.1 Unsegmented RLP Data Frames ................................................................ 4-5 15
4.3.2.2 Segmented RLP Data Frames .................................................................... 4-6 16
4.3.2.2.1 Rate 1/ 8 and Rate 1/ 16 Intersegment Fill Frames............................... 4-7 17
4.3.2.3 Primary Traffic .......................................................................................... 4-7 18
4.3.2.3.1 Full Rate Format A .............................................................................. 4-8 19
4.3.2.3.2 Full Rate Format B .............................................................................. 4-8 20
4.3.3 RLP Idle Frames.............................................................................................. 4-9 21 4
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Ballot Version Proposed TIA/ EIA/ PN-3676.2
FIGURES

iii
1
3.1.2.1-1 RLP Transmit Sequence Number .............................................................. 3-7 2
3.1.2.1-2 RLP Receive Sequence Number Variables ................................................. 3-7 3
4

5
6
TABLES 7
2.2.1-1 Primary Traffic Frame Types Supplied by the RLP to the 8
Multiplex Sublayer ................................................................................ 2-1 9

2.2.1-2 Primary Traffic Frame Types Supplied by the Multiplex Sublayer to 10
the RLP for Multiplex Option 1 .............................................................. 2-2 11

2.2.1-3 Primary Traffic Frame Types Supplied by the Multiplex Sublayer to 12
RLP for Multiplex Option 2 .................................................................... 2-2 13

2.2.2-1 Secondary Traffic Frame Types Supplied by the RLP to the Multiplex 14
Sublayer................................................................................................ 2-3 15

2.2.2-2 Secondary Traffic Frame Types Supplied by the Multiplex Sublayer to 16
RLP for Multiplex Option 1 .................................................................... 2-3 17

2.2.2-3 Secondary Traffic Frame Types Supplied by the Multiplex Sublayer to 18
RLP for Multiplex Option 2 .................................................................... 2-4 19

3.3.1-1 Fraction of Frames at Rate 1 and Rate 1/ 2 with Rate Reduction............. 3-17 20
3.3.1-2 Sequence Parameters for Rate Reduction ............................................... 3-18 21
3.3.2.1-1 Sequence Parameters for Rate Reduction ............................................... 3-19 22
3.3.2.2-1 Service Option Control Message Type-Specific Fields for 23
Traffic Channel Rate Control ............................................................... 3-19 24

3.3.2.2-2 Fraction of Frames at Rate 1 and Rate 1/ 2 with Rate Reduction............. 3-20 25
4.3.2.1-1 Values of the Maximum Allowable Data Length (MAX_ LEN) ...................... 4-6 26
4.3.3-1 Modified Nordstromđ Robinson Code ....................................................... 4-11 27
28 5
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Proposed TIA/ EIA/ PN-3676.2 Ballot Version
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Ballot Version Proposed TIA/ EIA/ PN-3676.2
1-1
1 INTRODUCTION 1
1.1 General Description 2
This chapter of TIA/ EIA/ IS-707 specifies procedures for the Radio Link Protocols 3
supporting the CDMA data services. The Radio Link Protocol specified for the Rate Set 1 4
multiplex sublayer is a compatible superset of the previous specifications for RLP found in 5
TIA/ EIA/ IS-99, and in TIA/ EIA/ IS-657. The Radio Link Protocol specified for the Rate Set 6
2 multiplex sublayer includes new frame definitions and new segmentation options. 7

The Radio Link Protocol (RLP) provides an octet stream transport service over forward and 8
reverse traffic channels. RLP is unaware of higher layer framing; it operates on a featureless 9
octet stream, delivering the octets in the order received. 10

The RLP may be either transparent or non-transparent. Transparent RLP provides 11
maximum throughput transmission of service option data over a CDMA traffic channel, 12
while maintaining bit count integrity over the air interface. The error rate for transparent 13
RLP is that observed on the traffic channel itself. Typically this requires that upper layer 14
data transmission protocols provide error recovery techniques equivalent to those provided 15
in the non-transparent RLP. 16

Non-transparent RLP substantially reduces the error rate exhibited by CDMA traffic 17
channels. There is no direct relationship between upper layer packets and the underlying 18
traffic channel frames; a large packet may span multiple traffic channel frames, or a single 19
traffic channel frame may contain all or part of several small upper layer packets. 20

Section 2 below is a general description of RLP that defines its use by any service option for 21
which it is suited. Section 3 defines the RLP procedures for encrypted or non-encrypted 22
applications. Section 4 defines the RLP frame formats. 23

1.2 Terms 24
Base Station (BS). A station in the Domestic Public Cellular Radio Telecommunications 25
Service, other than a mobile station, used for communicating with mobile stations. 26
Depending upon the context, the term base station may refer to a cell, a sector within a cell, 27
or other part of the cellular system. 28

BS. See base station. 29
BS/ MSC. The base station and mobile switching center considered as a single functional 30
entity. 31

Mobile Station. A station in the Domestic Public Cellular Radio Telecommunications 32
Service intended to be used while in motion or during halts at unspecified points. Mobile 33
stations include portable units (e. g., hand-held personal units) and units installed in 34
vehicles. 35

MSC. Mobile Switching Center. 36
RLP. Radio Link Protocol. 37 7
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Proposed TIA/ EIA/ PN-3676.2 Ballot Version
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1.3 References 1
ANSI/ J-STD-008 Personal Station-Base Station Compatibility Requirements for 2
1.8 to 2.0 GHz Code Division Multiple Access (CDMA) Personal 3
Communications Systems, Telecommunications Industry 4
Association, Washington, D. C. 5

TIA/ EIA/ IS-95-A Mobile Station-Base Station Compatibility Standard for Dual-6
Mode Wideband Spread Spectrum Cellular System, May, 1995. 7

TSB58 Administration of Parameter Value Assignments for TIA/ EIA 8
Wideband Spread Spectrum Standards, December, 1995. 9

TSB74 Support for 14.4 kbps Data Rate and PCS Interaction for 10
Wideband Spread Spectrum Cellular Systems, December, 1995. 11 8
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Ballot Version Proposed TIA/ EIA/ PN-3676.2
2-1
2 GENERAL REQUIREMENTS 1
2.1 Required Multiplex Option Support 2
For service options supporting an interface with Multiplex Option 1 or with Multiplex 3
Option 2, non-transparent RLP frames may be transported as primary traffic, or as 4
secondary traffic. Transparent RLP frames shall only be transported as primary traffic. 5

2.2 Interface to Multiplex Options 6
Transparent RLP frames are transported as primary traffic, while non-transparent RLP 7
frames can be carried as any traffic type. Section 2.2.1 applies to both transparent and 8
non-transparent RLP frames. Section 2.2.2 applies to non-transparent RLP frames only. 9

2.2.1 Primary Traffic 10
When carried as primary traffic, the RLP shall generate and supply exactly one frame 11
containing the service option bits to the multiplex sublayer every 20 milliseconds. The 12
frame shall be one of the types as shown in Table 2.2.1-1. The number of bits supplied to 13
the multiplex sublayer for each type of frame shall also be as shown in Table 2.2.1-1. 14
Unless otherwise commanded by Multiplex Option 1, RLP may supply a Rate 1, Rate 1/ 2, 15
Rate 1/ 8 or Blank frame. Unless otherwise commanded by Multiplex Option 2, RLP may 16
supply a Rate 1, Rate 1/ 2, Rate 1/ 4, Rate 1/ 8 or Blank frame. Upon command, the RLP 17
shall generate a Blank frame. A Blank frame contains no bits and is used for blank-and-18
burst transmission of signaling traffic (see 6.1.3.3.11 of TSB74) or when the RLP is unable 19
to send a segment of a segmented data frame. Also upon command, the RLP shall generate 20
a non-blank frame with a maximum rate of Rate 1/ 2. 21

22

Table 2.2.1-1. Primary Traffic Frame Types Supplied by the RLP to the Multiplex 23
Sublayer 24

RLP Frame Type Multiplex Option One
(bits per frame)
Multiplex Option Two
(bits per frame)

Rate 1 171 266
Rate 1/ 2 80 124
Rate 1/ 4 Not Used 54
Rate 1/ 8 16 20
Blank 0 0

25
The multiplex sublayer in the mobile station categorizes every received Traffic Channel 26
frame (see 6.2.2.2 of TSB74), and supplies the frame type and accompanying bits, if any, to 27
the RLP. Table 2.2.1-2 lists the frame types supplied by the multiplex sublayer when RLP 28
is carried as primary traffic by Multiplex Option 1. Although RLP does not generate Rate 29
1/ 4 frames, Multiplex Option 1 is not required to recognize this fact. RLP shall declare any 30 9
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Proposed TIA/ EIA/ PN-3676.2 Ballot Version
2-2
received Rate 1/ 4 frames to be erasures. Table 2.2.1-3 lists the frame types supplied by 1
the multiplex sublayer when RLP is carried as primary traffic by Multiplex Option 2. 2

3

Table 2.2.1-2. Primary Traffic Frame Types Supplied by the Multiplex Sublayer to the 4
RLP for Multiplex Option 1 5

RLP Frame
Type
Bits per
Frame
Multiplex Option 1
Frame Categories

Rate 1 171 1
Rate 1/ 2 80 2,6,11
Rate 1/ 4 40 3,7,12
Rate 1/ 8 16 4,8,13
Blank 0 5,14
Erasure 0 9,10

6
Table 2.2.1-3. Primary Traffic Frame Types Supplied by the Multiplex Sublayer to 7
RLP for Multiplex Option 2 8

RLP Frame
Type
Bits per
Frame
Multiplex Option 2
Frame Categories

Rate 1 266 1
Rate 1/ 2 124 2,6,11
Rate 1/ 4 54 3,7,12,15,19
Rate 1/ 8 20 4,8,10,13,16,18,20,22,24
Blank 0 5,9,14,17,21,23,25
Erasure 0 26

9

2.2.2 Secondary Traffic 10
When carried as secondary traffic, RLP shall generate and supply one frame containing the 11
service option bits to the multiplex sublayer every 20 milliseconds. The frame shall be one 12
of the types shown in Table 2.2.2-1. The number of bits supplied to the multiplex sublayer 13
for each type of frame shall also be as shown in Table 2.2.2-1. Upon command, the RLP 14
shall generate a Blank frame. A Blank frame contains no bits and is used for blank-and-15
burst transmission of signaling traffic (see 6.1.3.3.11 of TSB74), when primary traffic has 16
priority over secondary traffic and the primary traffic service option sends a Rate 1 frame, 17
or when the RLP is unable to send a segment of a segmented data frame (see 3.1.4). 18

19 10
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Ballot Version Proposed TIA/ EIA/ PN-3676.2
2-3
Table 2.2.2-1. Secondary Traffic Frame Types Supplied by the RLP to the Multiplex 1
Sublayer 2

RLP Frame Type Bits per Frame for
Multiplex Option 1
Bits per Frame for
Multiplex Option 2

Rate 1 168 262
Rate 7/ 8 152 242
Rate 3/ 4 128 208
Rate 1/ 2 88 138
Rate 7/ 16 Not Available 121
Rate 3/ 8 Not Available 101
Rate 1/ 4 Not Used 67
Rate 3/ 16 Not Available 52
Rate 1/ 8 Not Available 32
Rate 1/ 16 Not Available 20
Blank 0 0

3
The multiplex sublayer in the mobile station categorizes every received Traffic Channel 4
frame (see 6.2.2.2 of TSB74) and supplies the frame type and accompanying bits, if any, to 5
the RLP. Table 2.2.2-2 shows the frame types that may be sent to RLP by the multiplex 6
sublayer when RLP is carried as secondary traffic using Multiplex Option 1. Table 2.2.2-3 7
shows the frame types that may be sent to RLP by the multiplex sublayer when RLP is 8
carried as secondary traffic using Multiplex Option 2. 9

10

Table 2.2.2-2. Secondary Traffic Frame Types Supplied by the Multiplex Sublayer to 11
RLP for Multiplex Option 1 12

RLP Frame
Type
Bits per
Frame
Multiplex Option 1
Frame Categories

Rate 1 168 14
Rate 7/ 8 152 13
Rate 3/ 4 128 12
Rate 1/ 2 88 11
Blank 0 1-8
Erasure 0 9, 10

13 11
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Proposed TIA/ EIA/ PN-3676.2 Ballot Version
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Table 2.2.2-3. Secondary Traffic Frame Types Supplied by the Multiplex Sublayer to 1
RLP for Multiplex Option 2 2

RLP Frame
Type
Bits per
Frame
Multiplex Option 2
Frame Categories

Rate 1 262 9
Rate 7/ 8 242 8
Rate 3/ 4 208 7
Rate 1/ 2 138 6
Rate 7/ 16 121 17
Rate 3/ 8 101 16
Rate 1/ 4 67 15
Rate 3/ 16 52 23
Rate 1/ 8 32 22
Rate 1/ 16 20 10,18,25
Blank 0 1-5,11-14,19-21,24
Erasure 0 26

3

2.3 Traffic Channel Frame Priorities 4
2.3.1 Non-Transparent RLP 5
Each RLP layer shall classify the frames it sends into three priority classes. In order of 6
priority they are, with highest priority first: 7

1. RLP control frames 8
2. RLP data frames being resent in response to received NAK RLP control frames 9
3. RLP data frames being sent for the first time 10
When the multiplex sublayer indicates that it is ready to send a traffic channel frame, RLP 11
shall select the RLP frame with highest priority among those available for transmission. 12
When RLP is carried as primary traffic, and if no RLP frames in the above three classes are 13
available for transmission, an RLP idle frame (see 4.3.3) shall be sent. 14

When a service option using RLP is connected as primary traffic, and there is no service 15
option connected as secondary traffic, the mobile station should observe the following 16
priorities in using the traffic channel: 17

1. Signaling Traffic 18
2. RLP frames in priority class order 19 12
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Ballot Version Proposed TIA/ EIA/ PN-3676.2
2-5
When a service option using RLP is connected as secondary traffic, and a service option not 1
using RLP is connected as primary traffic, the mobile station should observe the following 2
priorities in using the traffic channel, if the primary traffic service option permits: 3

1. Signaling Traffic 4
2. RLP control frames, RLP retransmissions (RLP frames in priority classes 1 and 2), 5
and RLP transmissions due to idle timer expiration (see 3.1.2). If the primary 6
traffic service option permits, the multiplex sublayer should force primary traffic to 7
no more than half rate when these RLP frames iare transmitted. 8

3. Primary traffic service option data 9
4. New RLP data frames 10
When data from a service option using RLP over secondary traffic has a lower priority than 11
data from the service option using primary traffic, the blank and burst with secondary 12
traffic frame format (see 6.1.3.3 of TSB74) shall not be used unless the primary traffic 13
service option has no data to send. 14

When service options using RLP are connected as both primary and secondary traffic, the 15
mobile station should observe the following priorities in using the traffic channel: 16

1. Signaling Traffic 17
2. RLP control frames and RLP retransmissions (RLP frames in priority classes 1 and 18
2) pertaining to the service option connected as primary traffic. 19

3. RLP control frames, RLP retransmissions, and RLP transmissions (RLP layer 20
priority classes 1 and 2) due to idle timer expiration (see 3.1.2) pertaining to the 21
service option connected as secondary traffic. 22

4. New RLP data for the primary traffic service option (RLP frames in priority class 3). 23
5. New RLP data for the secondary traffic service option (RLP frames in priority class 24
3). 25

2.3.2 Transparent RLP Frame Priorities 26
When transparent RLP frames are carried as primary traffic, the following priorities should 27
be observed by the mobile station when using the traffic channel. 28

1. Signaling Traffic 29
2. Transparent RLP Data Frames 30
When a service option using transparent RLP is connected as primary traffic, and no RLP 31
frames are available for transmission, an RLP idle frame (see 4.3.3) shall be sent. 32

33 13
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Proposed TIA/ EIA/ PN-3676.2 Ballot Version
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Ballot Version Proposed TIA/ EIA/ PN-3676.2
3-1
3 RLP PROCEDURES 1
3.1 Non-Transparent RLP Procedures 2
Non-transparent RLP provides the capability of both non-encrypted mode and encrypted 3
mode data transport. The encryption capability is selected during RLP Initialization/ Reset 4
and is accomplished as a negotiation between the mobile station and the BS/ MSC. In 5
addition, a procedure for synchronizing RLP without encryption negotiation is also provided 6
here. The two techniques are compatible with each other and therefore can co-exist in 7
systems where encryption negotiation is supported in the infrastructure equipment, but 8
possibly not in some of the mobile stations attempting access to the system. 9

3.1.1 Initialization/ Reset Procedures 10
This standard defines two alternate RLP Initialization/ Reset procedures. Non-Encrypted 11
Mode initialization/ reset shall be used by mobile stations and BS/ MSCs that do not 12
support RLP data frame encryption for the desired service. Encrypted Mode 13
initialization/ reset procedures shall be used by mobile stations and BS/ MSCs to negotiate 14
the use of RLP data frame encryption. 15

3.1.1.1 Non-Encrypted Mode Initialization and Reset 16
Non-transparent RLP is established with a bidirectional handshake, after connection of the 17
service option that uses RLP, to synchronize the connection. To establish the RLP without 18
data encryption all control frames used (SYNC, ACK, and SYNC/ ACK) shall conform to the 19
Non-Encrypted Mode RLP control frame definitions (see 4.3.1). Accordingly, the control 20
frame names referenced in this section refer only to the Non-Encrypted Mode versions of 21
these frames. 22

When a traffic type carrying RLP frames is activated, when the traffic type carrying RLP 23
frames is changed, and at other times as specified in this standard or in other service 24
option standards, the RLP layer shall perform the initialization/ reset procedure below. 25

When the RLP layer is initialized or reset, and when a SYNC RLP control frame is received, 26
the RLP layer shall perform the following: 27

░ Reset the send and receive state variables V( S), V( R), and V( N) (defined in 3.1.2 ) to 28
zero. 29

░ Set the consecutive erasure count E (defined in 3.1.3 ) to zero. 30
░ Clear the resequencing buffers (defined in 3.1.2 ). 31
░ Disable all NAK retransmission timers and all NAK abort timers. 32
░ Discard any RLP data frames queued for retransmission. 33
░ Discard any RLP data frame being reassembled (see 3.1.4). 34
When the RLP layer is initialized or reset, it shall transmit a continuous stream of SYNC 35
RLP control frames (see 4.3.1). When the RLP layer receives a SYNC RLP control frame it 36
shall respond with a SYNC/ ACK RLP control frame, and shall continue sending SYNC/ ACK 37 15
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Proposed TIA/ EIA/ PN-3676.2 Ballot Version
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RLP control frames until the next valid frame which is not a SYNC RLP control frame is 1
received. When the RLP layer receives a SYNC/ ACK RLP control frame it shall respond with 2
an ACK RLP control frame, and shall continue sending ACK RLP control frames until the 3
next valid frame which is not a SYNC/ ACK control frame is received. When the RLP layer 4
receives an ACK RLP control frame, it shall send no more SYNC, SYNC/ ACK or ACK RLP 5
control frames, and should begin sending RLP data frames. 6

When RLP frames are carried as primary or secondary traffic, the RLP layer shall store in 7
RLP_ DELAY s the number of frames received between the sending of the last SYNC or 8

SYNC/ ACK RLP control frame and reception of the first valid frame that is not an ACK or 9
SYNC/ ACK RLP control frame. RLP_ DELAY s is used in NAK retransmission timing, as 10

described in 3.1.2.1. 11

3.1.1.2 Encrypted Mode RLP Initialization/ Reset 12
CDMA mobile stations complying with this standard may support authentication (see 13
6.3.12 of TIA/ EIA/ IS-95) and may support encryption of RLP data frames using the 14
procedures defined below. RLP data encryption shall be performed whenever cellular 15
authentication procedures have been performed during the establishment of a CDMA 16
Traffic Channel and RLP data encryption is negotiated (see 3.1.1.2.2). 17

3.1.1.2.1 Extended Data Frame Sequence Numbering 18
Mobile stations and BS/ MSCs supporting RLP data encryption shall support the following 19
extended data frame sequence numbering for RLP data frames. 20

The RLP layer shall maintain a 30-bit extended sequence number EXT_ V( S). EXT_ V( S) shall 21
be set to zero when the RLP Layer is initialized following the establishment of a Traffic 22
Channel. For all subsequent initializations/ resets of the RLP Layer while the Traffic 23
Channel remains established, the RLP Layer shall perform the following prior to sending an 24
Encrypted Mode SYNC or SYNC/ ACK control frame: 25

░ If the least significant 8 bits of EXT_ V( S) are not zero, the RLP Layer shall set the 26
least significant 8 bits of EXT_ V( S) to zero, and shall increment the most significant 27
22 bits of EXT_ V( S), modulo 2 22 . 28

░ If the least significant 8 bits of EXT_ V( S) are zero, the RLP Layer shall not change 29
EXT_ V( S). 30

For each RLP frame transmitted, the RLP Layer shall set the value of V( S) to the least 31
significant 8 bits of EXT_ V( S). EXT_ V( S) shall be incremented, following the procedures for 32
incrementing V( S) that are contained in 3.1.2.1 except that EXT_ V( S) shall be incremented 33
modulo 2 30 . 34

The RLP Layer shall maintain a 30-bit extended sequence number EXT_ V( R). When the 35
RLP Layer is initialized or reset, the RLP Layer shall set the least significant 8 bits of 36
EXT_ V( R) to zero. The most significant 22 bits of EXT_ V( R) shall be set as described in 37
3.1.1.2.2.1 or 3.1.1.2.2.2 as appropriate. 38 16
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When V( R) changes (see 3.1.2.1), the RLP Layer shall change EXT_ V( R) by the same 1
amount. 1 2

3.1.1.2.2 RLP Data Encryption Negotiation 3
When authentication is performed during the establishment of a CDMA Traffic Channel, the 4
mobile station and BS/ MSC shall set the input parameters of the DataKey_ Generation 5
procedure defined in "Common Cryptographic Algorithms, Revision A. 1" as follows: 6

░ In the mobile station, RAND shall be set to the stored value of RAND s . 7

░ In the BS/ MSC, RAND shall be set to the value of the RAND field of the Access 8
Parameters Message that was used for mobile station authentication. 9

░ The mobile station and BS/ MSC shall use the value of SSD_ B at the time of mobile 10
station authentication. 11

The mobile station and BS/ MSC shall then perform the DataKey_ Generation procedure. 12
The data encryption key (DataKey) and L table shall not change while the Traffic Channel is 13
established. 14

Mobile stations and BS/ MSCs supporting RLP data encryption shall perform negotiation of 15
RLP data encryption using the procedures in 3.1.1.2.2.1 or 3.1.1.2.2.2, respectively. 16

When the RLP Layer sends an Encrypted Mode SYNC or SYNC/ ACK RLP control frame with 17
the EM field set to '01', the RLP Layer shall set the EXT_ SEQ_ M field to the most significant 18
22 bits of the current value of EXT_ V( S). 19

If the EM field is not included in a received RLP control frame, the receiving RLP Layer shall 20
process the message as if EM were included and set to '00'. Throughout the following 21
procedures, the transmitting RLP Layer may send Non-Encrypted Mode RLP control frames 22
whenever the EM field would be set to '00'. 23

If the BS/ MSC requests RLP data encryption, the BS/ MSC may deny access to service if 24
authentication procedures (see 6.3.12 of TIA/ EIA/ IS-95-A) are not performed during Traffic 25
Channel establishment, or if the mobile station indicates by the setting of the EM field that 26
it does not perform RLP data encryption. 27

3.1.1.2.2.1 Mobile Station Negotiation Procedures 28
If the mobile station can perform RLP data encryption, the mobile station shall send an 29
Encrypted Mode SYNC RLP control frame to initiate Encrypted Mode Initialization/ Reset. 30
The mobile station's RLP Layer shall set the EM field to '01' and shall set the EXT_ SEQ_ M 31
field to the most significant bits of the mobile station's current value of EXT_ V( S). 32

If the mobile station cannot perform RLP data encryption, the mobile station's RLP Layer 33
shall set the EM field to '00' (or equivalently, send a Non-Encrypted Mode SYNC RLP control 34
frame to initiate Non-Encrypted Mode initialization/ reset). 35

1 That is, if the old value of V( R) is A and the new value of V( R) is B, EXT_ V( R) is incremented by
(256+ B-A) modulo 256. All arithmetic operations on EXT_ V( R) are modulo 2 30 . 17
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Proposed TIA/ EIA/ PN-3676.2 Ballot Version
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When the mobile station RLP Layer receives an Encrypted Mode SYNC RLP control frame, it 1
shall perform the following: 2

░ If the EM field of the received frame is set to '01', and the mobile station can perform 3
RLP data encryption, the RLP Layer shall set the EM field of transmitted Encrypted 4
Mode SYNC/ ACK RLP control frames to '01', shall set the EXT_ SEQ_ M field of the 5
transmitted frames to the most significant 22 bits of the mobile station's current 6
value of EXT_ V( S), and shall set the most significant 22 bits of EXT_ V( R) to the value 7
of the EXT_ SEQ_ M field of the received frame. 8

░ If the EM field of the received frame is set to any other value, or if the mobile station 9
does not perform data encryption, the RLP Layer shall set the EM field of transmitted 10
Encrypted Mode SYNC/ ACK RLP control frames to '00' and shall set the most 11
significant 22 bits of EXT_ V( R) to zero. 12

When the mobile station RLP Layer receives an Encrypted Mode SYNC/ ACK RLP control 13
frame, it shall perform the following: 14

░ If the EM field of the received frame is set to '01', and the mobile station can perform 15
RLP data encryption, the RLP Layer shall set the EM field of transmitted Encrypted 16
Mode ACK RLP control frames to '01' shall set the EXT_ SEQ_ M field of the 17
transmitted frame to the most significant 22 bits of the mobile station's current value 18
of EXT_ V( S), and shall set the most significant 22 bits of EXT_ V( R) to the value of the 19
EXT_ SEQ_ M field in the received frame. The RLP Layer shall encrypt all transmitted 20
RLP data frames and shall decrypt all received RLP data frames, following the 21
procedures of 3.1.2.2.1 and 3.1.2.2.2. 22

░ If the EM field of the received frame is set to '01', but the mobile station does not 23
perform RLP data encryption, the RLP Layer shall perform the Non-Encrypted Mode 24
RLP initialization/ reset procedure (see 3.1.1.1). 25

░ If the EM field of the received frame is set to any value other than '01', the RLP Layer 26
shall set the EM field of transmitted Encrypted Mode ACK RLP control frames to '00' 27
and shall set the most significant 22 bits of EXT_ V( R) to zero. The RLP Layer shall 28
not encrypt nor decrypt RLP data frames. 29

When the mobile station RLP Layer receives an Encrypted Mode ACK RLP control frame, it 30
shall perform the following: 31

░ If the EM field of the received frame is set to '01', and the mobile station can perform 32
RLP data encryption, the RLP Layer shall encrypt all transmitted RLP data frames 33
and shall decrypt all received RLP data frames, following the procedures of 3.1.2.2.1 34
and 3.1.2.2.2. 35

░ If the EM field of the received frame is set to '01', but the mobile station does not 36
perform RLP data encryption, the RLP Layer shall perform the Non-Encrypted Mode 37
RLP initialization/ reset procedure (see 3.1.1.1). 38

░ If the EM field of the received frame is set to any value other than '01', the RLP Layer 39
shall not encrypt nor decrypt RLP data frames. 40 18
18 Page 19 20
Ballot Version Proposed TIA/ EIA/ PN-3676.2
3-5
3.1.1.2.2.2 BS/ MSC Negotiation Procedures 1
When the BS/ MSC RLP Layer transmits an Encrypted Mode SYNC RLP control frame, it 2
shall perform the following: 3

░ If the BS/ MSC requests RLP data encryption, the RLP Layer shall set the EM field to 4
'01' and shall set the EXT_ SEQ_ M field to the most significant 22 bits of the 5
BS/ MSC's current value of EXT_ V( S). Otherwise, the RLP Layer shall set the EM field 6
to '00' (or, equivalently, transmit an Unencrypted Mode RLP SYNC control frame as 7
discussed in 3.1.1.2.2). The RLP Layer should set the EM field to '00' if encryption is 8
provided by the Link Layer or higher layers. 2 9

When the BS/ MSC RLP Layer receives an Encrypted Mode SYNC RLP control frame, it shall 10
perform the following: 11

░ If the EM field of the received frame is set to '01', and the BS/ MSC requests RLP data 12
encryption, the RLP Layer shall set the EM field of transmitted Encrypted Mode 13
SYNC/ ACK RLP control frames to '01', shall set the EXT_ SEQ_ M field of the 14
transmitted frames to the most significant 22 bits of the BS/ MSC's current value of 15
EXT_ V( S), and shall set the most significant 22 bits of EXT_ V( R) to the value of the 16
EXT_ SEQ_ M field of the received frame. 17

░ If the EM field of the received frame is set to any other value, or if the BS/ MSC does 18
not request data encryption, the RLP Layer shall set the EM field of transmitted 19
Encrypted Mode SYNC/ ACK RLP control frames to '00' and shall set the most 20
significant 22 bits of EXT_ V( R) to zero. 21

When the BS/ MSC RLP Layer receives an Encrypted Mode SYNC/ ACK RLP control frame, it 22
shall perform the following: 23

░ If the EM field of the received frame is set to '01', and the BS/ MSC requests RLP data 24
encryption, the RLP Layer shall set the EM field of transmitted Encrypted Mode ACK 25
RLP control frames to '01', shall set the EXT_ SEQ_ M field of the transmitted frame to 26
the most significant 22 bits of the BS/ MSC's current value of EXT_ V( S), and shall set 27
the most significant 22 bits of EXT_ V( R) to the value of the EXT_ SEQ_ M field in the 28
received frame. The RLP Layer shall encrypt all transmitted RLP data frames and 29
shall decrypt all received RLP data frames, following the procedures of 3.1.2.2.1 and 30
3.1.2.2.2. 31

░ If the EM field of the received frame is set to '01', but the BS/ MSC does not request 32
RLP data encryption, the RLP Layer shall perform the Non-Encrypted Mode RLP 33
initialization/ reset procedure (see 3.1.1.1). 34

░ If the EM field of the received frame is set to any value other than '01', the RLP Layer 35
shall set the EM field of transmitted Encrypted Mode ACK RLP control frames to '00' 36
and shall set the most significant 22 bits of EXT_ V( R) to zero. The RLP Layer shall 37
not encrypt nor decrypt RLP data frames. 38

2 It is anticipated that future revisions of PPP, IP and other protocols may include encryption. 19
19 Page 20 21
Proposed TIA/ EIA/ PN-3676.2 Ballot Version
3-6
When the BS/ MSC RLP Layer receives an Encrypted Mode ACK RLP control frame, it shall 1
perform the following: 2

░ If the EM field of the received frame is set to '01', and the BS/ MSC requests RLP data 3
encryption, the RLP Layer shall encrypt all transmitted RLP data frames and shall 4
decrypt all received RLP data frames, following the procedures of 3.1.2.2.1 and 5
3.1.2.2.2. 6

░ If the EM field of the received frame is set to '01', but the BS/ MSC does not request 7
RLP data encryption, the RLP Layer shall perform the Non-Encrypted Mode RLP 8
initialization/ reset procedure (see 3.1.1.1). 9

░ If the EM field of the received frame is set to any value other than '01', the RLP Layer 10
shall not encrypt nor decrypt RLP data frames. 11

3.1.2 Data Transfer 12
3.1.2.1 Non-Encrypted Data Transfer 13
When transferring data, non-transparent RLP is a pure NAK-based protocol. That is, the 14
receiver does not acknowledge correct RLP data frames; it only requests the retransmission 15
of RLP data frames that were not received. 16

All operations on RLP frame sequence numbers shall be carried out in unsigned modulo 17
256 arithmetic. Comparisons of two RLP frame sequence numbers shall also be modulo 18
256: for any RLP frame sequence number N, those sequence numbers from (N+ 1) modulo 19
256 to (N+ 127) modulo 256, inclusive, shall be considered greater than N while all sequence 20
numbers from (N-128) modulo 256 to (N-1) modulo 256, inclusive, shall be considered less 21
than N. 3 22

The RLP layer shall maintain an 8-bit sequence number count V( S) for all transmitted RLP 23
data frames (see Figure 3.1.2.1-1). The sequence number field (SEQ) in each new RLP data 24
frame sent and in each RLP idle frame sent shall be set to V( S). V( S) shall be incremented, 25
modulo 256, after formatting each new RLP data frame sent that contains a non-zero 26
number of data octets. V( S) shall not be incremented after an RLP idle frame is sent. New 27
RLP data frames shall not be segmented. 28

29

3 Note that (N-1) modulo 256 is equal to (N+ 255) modulo 256, and (N-128) modulo 256 is equal to
(N+ 128) modulo 256. 20
20 Page 21 22
Ballot Version Proposed TIA/ EIA/ PN-3676.2
3-7
Frames sent
Frames awaiting transmission

V( S) = sequence number of next frame to be sent
░ ░ ░ ░ ░ ░

1
Figure 3.1.2.1-1. RLP Transmit Sequence Number 2

3

The RLP layer shall maintain two 8-bit sequence number variables for receiving, V( R) and 4
V( N) (see Figure 3.1.2.1-2). V( R) contains the expected value of the RLP frame sequence 5
number field in the next new traffic channel frame to be received. V( N) contains the 6
sequence number of the next needed traffic channel frame not received in sequence, as 7
described below. 8

9

Frames received in sequence
Frames received out of sequence

V( R) = next new frame expected
░ ░ ░ ░ ░ ░

Buffer space for new or missed data frames

V( N) = next frame needed for sequential delivery

10
Figure 3.1.2.1-2. RLP Receive Sequence Number Variables 11

12

The RLP layer shall provide a storage buffer for resequencing of out-of-sequence RLP data 13
frames both on the transmitting and on the receiving side. 4 These buffers shall each be 14
able to store no fewer than 128 RLP data frames of the maximum size allowed for the traffic 15
type carrying RLP. 16

4 i. e, two such buffers are required in a mobile station. 21
21 Page 22 23
Proposed TIA/ EIA/ PN-3676.2 Ballot Version
3-8
For each received RLP data frame that is valid and contains a non-zero number of data 1
octets, the RLP layer shall compare the sequence number to V( R) and V( N). Criteria for 2
frame validity are given in 3.1.3. 3

░ If the received RLP frame sequence number is less than V( N), or if the RLP data frame 4
is already stored in the resequencing buffer, the RLP data frame shall be discarded as 5
a duplicate. 6

░ If the received RLP frame sequence number is greater than or equal to V( N) and less 7
than V( R), and the RLP data frame is not already stored in the resequencing buffer, 8
then: 9

-If the received frame is an unsegmented RLP data frame the RLP layer shall store 10
the received RLP data frame in the resequencing buffer. 11

-If the received frame is a segmented RLP data frame, the segment shall be 12
reassembled as specified in 3.1.4. 13

-If the complete RLP data frame has been received, and the RLP frame sequence 14
number is equal to V( N), the RLP layer shall pass the data in all contiguous RLP 15
data frames in the resequencing buffer, from V( N) upward, to the higher layer, 16
and shall remove the passed frames from the resequencing buffer. The RLP 17
layer shall then set V( N) to (LAST+ 1) modulo 256 where LAST is the sequence 18
number of the last RLP data frame passed to the higher layer from the 19
resequencing buffer. 20

░ If the received RLP frame sequence number equals V( R), then: 21
-If the received frame is a segmented RLP data frame, the frame shall be 22
discarded without further processing. Otherwise, the frame shall be processed 23
as follows: 24

-If V( R) equals V( N), the RLP layer shall increment V( N) and V( R), modulo 256, 25
and shall pass all data octets in the RLP data frame to the higher layer. 26

-If V( R) is not equal to V( N), the RLP layer shall increment V( R), modulo 256, and 27
shall store the received RLP data frame in the resequencing buffer. 28

░ If the received sequence number is greater than V( R), then: 29
-If the received frame is a segmented RLP data frame, the frame shall be 30
discarded without further processing. Otherwise, the frame shall be processed 31
as follows: 32

-The RLP layer shall store the received RLP data frame in the resequencing buffer 33
and shall set V( R) equal to the received sequence number. 34

-The RLP layer shall then send one or more NAK RLP control frames requesting 35
the retransmission of all unreceived RLP data frames from V( N) to (V( R)-1) 36
modulo 256, inclusive. RLP data frames requested in a previous NAK RLP 37
control frame whose NAK retransmission counter or NAK abort counter has not 38
expired should not be included in these NAK RLP control frames. 39

-The RLP layer shall then increment V( R), modulo 256. 40 22
22 Page 23 24
Ballot Version Proposed TIA/ EIA/ PN-3676.2
3-9
The RLP layer shall also compare the sequence number in each valid received RLP idle 1
frame and NAK RLP control frame to V( R). 2

░ If the received RLP frame sequence number equals V( R), the RLP layer shall take no 3
further action. 4

░ If the received RLP frame sequence number is greater than V( R), the RLP layer shall 5
set V( R) to the received frame sequence number, and shall then send one or more 6
NAK control frames requesting the retransmission of all unreceived RLP data frames 7
with sequence numbers V( N) to (V( R)-1) modulo 256, inclusive. RLP data frames 8
requested in a previous NAK RLP control frame whose NAK retransmission counter or 9
NAK abort counter has not expired should not be included in these NAK frames. 10

On receiving a NAK, the RLP layer shall insert copies of the requested RLP data frame( s) 11
into its output stream. If the NAK includes any sequence number greater than or equal to 12
V( S), 5 the RLP layer shall perform the initialization/ reset procedures specified in 3.1.1.1 or 13
3.1.1.2. 14

If the size of a retransmitted frame is less than or equal to the number of octets available in 15
the traffic channel frame at the time of retransmission, an unsegmented frame (see 4.3.2.1 16
and 4.3.2.3.2) shall be used. If the size of a retransmitted frame exceeds the number of 17
octets available in the traffic channel frame at the time of retransmission, the RLP layer 18
may segment the frame as specified in 3.1.4. 19

The RLP layer shall maintain a NAK retransmission timer for each RLP data frame 20
requested in a NAK RLP control frame. 21

The NAK retransmission timer shall be implemented as a frame counter. The NAK 22
retransmission counter shall be incremented for each valid RLP idle frame and for each 23
valid new RLP data frame (sequence number greater than or equal to V( R)) received on the 24
traffic type where the RLP is carried. When RLP frames are carried as primary traffic, the 25
RLP receiver shall not increment the NAK retransmission counter upon receiving a Blank 26
RLP frame. 27

When RLP is used with Multiplex Option 1 and is carried as secondary traffic, frame types 28
2, 3, 4, and 5 (see 6.2.2.2.2 of TIA/ EIA/ IS-95) are not considered RLP frames and are not 29
counted. 30

When RLP is used with Multiplex Option 2 and is carried as secondary traffic, frame types 31
3, 4 and 5 (see 6.2.2.2.1 of TIA/ EIA/ IS-95) are not considered RLP frames and are not 32
counted. 33

The NAK retransmission counter shall not be incremented on receiving erasures (as defined 34
in 3.1.3), RLP control frames, Intersegment Fill frames nor old RLP data frames (sequence 35

5 This would indicate that the NAK process has fallen behind the sequence numbering by more than
128 frames. 23
23 Page 24 25
Proposed TIA/ EIA/ PN-3676.2 Ballot Version
3-10
number less than V( R)). The NAK retransmission counter shall be considered expired when 1
it is incremented to an implementation dependent value greater than RLP_ DELAY s . 6 2

If any RLP data frame requested has not arrived when its NAK retransmission timer expires, 3
the receiver shall send one or more NAK RLP control frames requesting the retransmission 4
of all unreceived RLP data frames from V( N) upward. RLP data frames requested in a 5
previous NAK RLP control frame whose NAK retransmission timer or NAK abort timer has 6
not expired should not be included in these NAK frames. Each NAK RLP control frame 7
transmitted as the result of a NAK retransmission timer expiration shall be transmitted 8
twice. The RLP layer shall then restart the NAK retransmission timer for the RLP data 9
frames requested. 10

If any RLP data frame requested has not arrived when its NAK retransmission timer expires 11
for the second time, the receiver shall send one or more NAK RLP control frames requesting 12
the retransmission of all unreceived RLP data frames from V( N) upward. RLP data frames 13
requested in a previous NAK RLP control frame whose NAK retransmission timer or NAK 14
abort timer has not expired should not be included in these NAK frames. Each NAK RLP 15
control frame transmitted as the result of a second NAK retransmission timer expiration 16
shall be transmitted three times. The RLP layer shall then start a NAK abort timer for the 17
RLP data frames requested. The NAK abort timer shall be implemented, and shall be 18
considered expired, according to the same rules as a NAK retransmission timer. 19

If any RLP data frame requested has not arrived when its NAK abort timer expires, the RLP 20
layer shall set V( N) to the sequence number of the next missing frame, or to V( R) if there are 21
no remaining missing frames. The RLP layer shall then pass any RLP data frames with 22
sequence numbers less than V( N) in order of sequence number to the higher layer. Further 23
recovery is the responsibility of the upper layer protocols. 24

The RLP layer shall perform the following whenever RLP frames are carried as secondary 25
traffic: 26

░ Whenever a new RLP data frame is sent, the RLP layer shall start an idle timer. The 27
implementation and expiration criteria for the idle timer shall be the same as for a 28
NAK retransmission timer (see above), except that all traffic channel frames shall be 29
counted toward timer expiration. The RLP layer shall also maintain an idle frame 30
transmission counter, which shall initially be set to zero. The timer shall be 31
restarted, and the idle frame transmission counter shall be reset to zero, following 32
the transmission of any RLP frame prior to the expiration of the timer. When the idle 33
timer expires, the RLP layer shall transmit an RLP control frame or an RLP idle 34
frame 7 containing the current data frame sequence number V( S), shall increment the 35
idle frame transmission count, and shall restart the idle timer. If the idle frame 36
transmission count equals 3, the idle timer shall be disabled. 37

6 It is recommended that a guard interval of five frames be added to the retransmission timeout to
account for buffering within the TIA/ EIA/ IS-95-A mobile or base station and for segmentation of
retransmitted frames.

7 When RLP is carried as secondary traffic, an RLP idle frame is an RLP data frame with zero length
(see 4.3.2.1). 24
24 Page 25 26
Ballot Version Proposed TIA/ EIA/ PN-3676.2
3-11
3.1.2.2 Encrypted Data Transfer 1
3.1.2.2.1 Encryption 2
When RLP data encryption is negotiated, the Data octets of all transmitted RLP data frames 3
shall be encrypted, using the following procedures. 4

Encryption mask generation shall be in accordance with the Data_ Mask procedure defined 5
in "Common Cryptographic Algorithms, Revision A. 1." When an RLP data frame is 6
transmitted, the RLP layer shall set the input parameters of the Data_ Mask procedure, 7
HOOK and LEN (see "Interface Specification for Common Cryptographic Algorithms, 8
Revision A. 1") as follows: 9

░ If the RLP data frame is transmitted by a mobile station, the RLP layer shall set 10
HOOK equal to EXT_ V( S) (see 3.1.1.2.1), with the two most significant bits of HOOK 11
set to '00'. 12

░ If the RLP data frame is transmitted by a BS/ MSC, the RLP layer shall set HOOK 13
equal to EXT_ V( S) (see 3.1.1.2.1), and shall then set the most significant bits of 14
HOOK to '01'. 15

░ The length of the mask (LEN) shall be equal to the number of octets in the Data part 16
of the RLP data frame. 17

The RLP layer shall then execute the Data_ Mask procedure. 18
Each octet of the Data part of the RLP data frame shall be combined with the mask by 19
bitwise exclusive-or, combining successive data octets with mask octets. 20

RLP data frames that are retransmitted shall be encrypted using the same mask as when 21
first transmitted. 22

If an RLP data frame for retransmission is to be sent as segmented RLP data, the data 23
frame shall be encrypted prior to its segmentation. 24

3.1.2.2.2 Decryption 25
For each RLP data frame received, the RLP layer shall form an extended sequence number 26
EXT_ SEQ which shall be set equal to EXT_ V( R) (see 3.1.1.2.1) minus the difference between 27
V( R) (see 3.1.2.1) and the received sequence number. 8 For this calculation, if the received 28
sequence number changes V( R) and EXT_ V( R), the new values of V( R) and EXT_ V( R) shall 29
be used in the calculation of EXT_ SEQ. 9 30

When an encrypted RLP data frame is received, the RLP layer shall set the input parameters 31
of the Data_ Mask procedure (see "Interface Specification for Common Cryptographic 32
Algorithms, Revision A. 1") as follows: 33

8 That is, if the received sequence number is N, EXT_ SEQ s is set to EXT_ V( R) -(( 256+ V( R)-N) modulo
256).
9 This ensures that the received sequence number is never less than V( R). 25
25 Page 26 27
Proposed TIA/ EIA/ PN-3676.2 Ballot Version
3-12
░ If the RLP data frame is received from a mobile station, the RLP layer shall set HOOK 1
equal to EXT_ SEQ, with the two most significant bits of HOOK set to '00'. 2

░ If the RLP data frame is received from a BS/ MSC, the RLP layer shall set HOOK equal 3
to EXT_ SEQ, and shall then set the most significant bits of HOOK to '01'. 4

░ The length of the mask (LEN) shall be equal to the number of octets in the Data part 5
of the RLP data frame. 6

The RLP layer shall then execute the Data_ Mask procedure. 7
Each octet of the Data part of the RLP data frame shall be combined with the mask by 8
bitwise exclusive-or, combining successive data octets with mask octets. 9

If a retransmitted RLP data frame is received as 2 or more segmented RLP frames, the 10
unsegmented frame shall be reassembled prior to decrypting the data. 11

3.1.3 Frame Validity Checks 12
3.1.3.1 Primary Traffic 13
When RLP frames are carried as primary traffic, the RLP layer shall discard as invalid all 14
traffic channel frames received for which any of the following applies: 15

1. The traffic channel frame is classified into category 3, 7, 9, 10 or 12 by Multiplex 16
Option 1 (see 6.2.2.2.1 of TSB74) or into category 26 by Multiplex Option 2 (see 17
6.2.2.2.2 of TSB74). All such traffic channel frames shall be counted as 18
"erasures 10 " by RLP. 19

2. For RLP control frames, the FCS field does not check; for eighth and sixteenth rate 20
intersegment fill frames and eighth-rate RLP idle frames, the FCS field is not the 21
correct value for the value of the SEQ field. All such traffic channel frames shall be 22
counted as "erasures" by RLP. 23

3. RLP frame TYPE field value is not one of the values defined in 4.3. 24
4. RLP frame LEN field value is not within the range allowed in 4.3. 25
5. RLP frame CTL field value is not a value as defined in 4.3. 26
6. For Rate 1/ 8 and Rate 1/ 16 frames only, the received RLP frame sequence number 27
is not within the range from V( R) to (V( R)+ E) modulo 256, inclusive, where E is the 28
number of consecutive erasures (see (1) and (2) above) preceding the current frame, 29
and V( R) is as defined in 3.1.2.1. 30

7. For Rate 1/ 8 frames only, the frame is not identical in contents to the preceding 31
frame. 32

All other traffic channel frames shall be considered valid. 33

10 The "erasures" defined here serve to inhibit incrementing of the NAK retransmission timer. They
are not to be confused with TIA/ EIA/ IS-95 frame erasures. 26
26 Page 27 28
Ballot Version Proposed TIA/ EIA/ PN-3676.2
3-13
If three consecutive identical Rate 1/ 8 frames arrive with a sequence number that is out of 1
the acceptable range, as defined in (6) above, then: 2

░ If the third received sequence number is greater than V( R), the RLP layer shall 3
consider the third frame and its sequence number as valid and shall process the 4
frame as specified in 3.1.2.1. 5

░ If the third received sequence number is less than V( R), the RLP layer shall perform 6
the initialization/ reset procedure specified in 3.1.1. 7

The RLP layer shall maintain a count E of the consecutive frames classified as "erasures," 8
as defined in (1) above. If the consecutive erasure count E exceeds 127, the RLP layer shall 9
perform the initialization/ reset procedure specified in 3.1.1. 10

3.1.3.2 Secondary Traffic 11
When RLP frames are carried as secondary traffic, the RLP layer shall discard as invalid all 12
traffic channel frames received for which any of the following applies: 13

1. The traffic channel frame is classified into category 9 or 10 by Multiplex Option 1 or 14
into category 26 by Multiplex Option 2 (see 6.2.2.2 of TSB74). All such frames 15
shall be counted as "erasures" by RLP. All other frame categories that do not 16
include secondary traffic are ignored by RLP; only those listed here shall be 17
classified as erasures. 18

2. For RLP control frames, idle frames and Rate 1/ 8 and Rate 1/ 16 intersegment fill 19
frames, the FCS field does not check. 20

3. RLP frame TYPE field value is not one of the values defined in 4.3. 21
4. RLP frame LEN field value is not within the range allowed in 4.3. 22
5. RLP frame CTL field value is not a value as defined in 4.3. 23
All other traffic channel frames shall be considered valid, and shall be processed by RLP if 24
they contain secondary traffic data. 25

The RLP layer shall maintain a count E of the consecutive frames classified as "erasures," 26
as defined in (1) above. 27

If the consecutive erasure count E exceeds 127, the RLP layer shall perform the 28
initialization/ reset procedure specified in 3.1.1. 29

3.1.4 Segmentation of Retransmitted Data Frames 30
The following procedures apply to the segmentation and reassembly of RLP data frames. 31
Segmentation may be necessary when a retransmitted frame size exceeds the number of 32
octets available at the time the retransmission occurs. 33 27
27 Page 28 29
Proposed TIA/ EIA/ PN-3676.2 Ballot Version
3-14
The RLP layer procedures below assure that no more than three data bearing segments are 1
needed to transmit an RLP frame by requiring all but the last segment to use at least a Rate 2
3/ 8 frame. 11 3

A retransmitted RLP data frame may be sent in one, two or three segments. If the 4
retransmitted frame is sent in a single segment, an unsegmented frame (see 4.3.2.1 and 5
4.3.2.3.2) is used. If the retransmitted RLP data frame size exceeds the number of octets 6
available at the time the retransmission occurs, the RLP layer should segment the frame. 7
With the exception of intersegment fill frames, all RLP segmented frames except the last 8
segmented frame shall be sent using Rate 3/ 8 or larger RLP frames. 9

When Rate Set 2 is used, an Intersegment Fill frame (see 4.3.2.2 and 4.3.2.2.1) can be sent 10
by the BS/ MSC. Mobile stations complying with this standard shall not transmit 11
intersegment fill frames on the reverse link. When the intersegment fill frame is used the 12
sequence number of an Intersegment Fill frame shall be set equal to the sequence number 13
of the RLP data frame being retransmitted. 14

The RLP layer segments the frame using the following procedure: 15
░ The first segment shall be transmitted using the First Segment frame type (see 16
4.3.2.2). The first segment should contain the maximum number of data octets 17
available. If RLP is carried on Multiplex Option 2, and less than a Rate 3/ 8 RLP 18
frame is available, a Blank RLP frame should be provided to the multiplex sublayer. 19
Alternately, an Intersegment Fill frame (see 4.3.2.2 and 4.3.2.2.1) may be sent. 20

░ If the number of octets remaining after the transmission of a First Segment frame 21
type exceeds the number of octets available at the time of transmission of the next 22
segment, the next segment shall be transmitted using the Second Segment frame 23
type (see 4.3.2.2). Otherwise, the next segment shall be transmitted using the Last 24
Segment frame type (see 4.3.2.2). If RLP is carried on Multiplex Option 2, and less 25
than a Rate 3/ 8 RLP frame is available, a Blank RLP frame should be provided to the 26
multiplex sublayer. Alternately, an Intersegment Fill frame (see 4.3.2.2 and 4.3.2.2.1 27
may be sent. 28

░ If the number of octets remaining after the transmission of a First or Second Segment 29
frame type is less than or equal to the number of octets available at the time of 30
transmission of the next segment, the next segment shall be transmitted using the 31
Last Segment frame type (see 4.3.2.2). If RLP is carried on Multiplex Option 2, and 32
the number of octets remaining after the transmission of a Second Segment frame 33
type exceeds the number of octets available at the time of transmission of the next 34
segment, a Blank RLP frame should be provided to the multiplex sublayer. 35
Alternately, an Intersegment Fill frame (see 4.3.2.2 and 4.3.2.2.1) may be sent. 36

░ Segmented RLP data frames shall not be sent with the LEN field equal to zero. 37
░ The SEQ fields of all segments shall be set to the sequence number of the RLP data 38
frame being retransmitted. 39

11 For Multiplex Option 1, the smallest available frame that carries data is Rate 1/ 2, which is larger
than Rate 3/ 8. 28
28 Page 29 30
Ballot Version Proposed TIA/ EIA/ PN-3676.2
3-15
░ The RLP layer may transmit RLP control frames between segments of a segmented 1
RLP data frame. For Multiplex Option 1, the RLP layer may transmit eighth rate idle 2
frames (see 4.3.3) between segments of a segmented RLP data frame. For Multiplex 3
Option 2, the RLP layer shall not transmit idle frames between segments of a 4
segmented RLP data frame. The RLP layer shall not transmit other RLP data frames 5
nor segments with different sequence numbers between segments of a segmented 6
RLP data frame. 7

The RLP layer shall begin frame reassembly on receipt of the first segment of a segmented 8
RLP data frame. When RLP is carried with Multiplex Option 2, if an Intersegment Fill frame 9
is received, the RLP layer shall discard it. When the last segment of the RLP data frame is 10
received, the RLP layer shall process the RLP data frame in the same manner as if it had 11
been unsegmented (see 4.3.2.1). 12

The RLP layer shall discard, without further processing, any segmented RLP data frame 13
that is received under any of the following conditions: 14

░ If a segment is received out of order (e. g., a last or second segment received without 15
receiving a first segment). 16

░ If an invalid frame (see 3.1.3) is received at any time between the first and last 17
segments. 18

░ If an RLP data frame or segment with a different sequence number is received 19
between the first and last segments. 20

░ When RLP is carried using Multiplex Option 2, if an idle frame (see 4.3.3) is received 21
at any time between the First Segment frame and Last Segment frame. 22

3.2 Transparent RLP Procedures 23
3.2.1 Initialization 24
Transparent RLP maintains two state variables, V( S), and V( R) (see 3.2.2). When a service 25
option using transparent RLP is connected, the transparent RLP layer shall perform the 26
following: 27

░ Transparent RLP shall set counters V( S) and V( R) to zero. 28
░ Transparent RLP shall send an initialization indication to the upper layer. 29
Following the initialization procedure the transparent RLP may begin delivering frames to 30
and accepting frames from the multiplex sublayer. 31

3.2.2 Data Transfer 32
Transparent RLP does not provide any retransmission of erased frames. It is the 33
responsibility of the upper layers to provide further synchronization and error recovery 34
when Transparent RLP is used. 35

Transparent RLP shall maintain two eight-bit sequence number variables, V( S) (for 36
transmitting) and V( R) (for receiving). See 3.2.1 for initialization procedures for these state 37
variables. 38 29
29 Page 30 31
Proposed TIA/ EIA/ PN-3676.2 Ballot Version
3-16
If Transparent RLP has no data to send, Transparent RLP generates and transmits an idle 1
RLP frame (see 4.3.3). When an idle RLP frame is sent, transparent RLP shall set the SEQ 2
field to the current value of V( S). V( S) shall not be incremented when Transparent RLP 3
sends an idle RLP frame. When an idle RLP frame is received by Transparent RLP, 4
Transparent RLP may discard it. 5

When a transparent RLP frame is to be transmitted the RLP transmitter shall perform the 6
following: 7

░ The RLP transmitter shall copy the current value of V( S) into the SEQ field of the 8
frame to be transmitted. 9

░ The RLP transmitter shall set the LEN field of the frame to the number of data octets 10
to be transmitted. 11

░ The remainder of the frame shall be formatted in accordance with the valid frame 12
formats for transparent RLP defined in 4.3.2.1 and 4.3.2.3.1. 13

░ The RLP transmitter shall increment V( S) modulo 256 for every octet of service option 14
data carried in the RLP frame. 15

░ The RLP transmitter shall deliver the formatted frame to the multiplex sublayer in 16
accordance with the interface requirements for Multiplex Option 1 or 2 as 17
appropriate. 18

When a transparent RLP data frame is received the transparent RLP receiver shall perform 19
the following: 20

░ The transparent RLP receiver shall compare the value of the received SEQ field with 21
V( R). 22

-If the value of SEQ equals V( R) then: 23

+ The RLP receiver shall update V( R) by adding the value of LEN to the value of 24
V( R) modulo 256 and, 25

+ The RLP receiver shall pass the contents of the received RLP data frame to 26
the upper layer. 27

-If the value of SEQ is less than the value of V( R) then: 28

+ The transparent RLP layer shall pass the value of 256-( V( R)-SEQ) (the 29
number of octets previously lost) and the contents of the received RLP data 30
frame to the upper layer. 31

+ The transparent RLP layer shall set the value of V( R) to the value of 32
(SEQ+ LEN) modulo 256. 33

-If the value of SEQ is greater than the value of V( R) then: 34

+ The transparent RLP layer shall pass the value of SEQ-V( R) (the number of 35
octets previously lost) and the contents of the received RLP data frame to the 36
upper layer. 37

+ The transparent RLP layer shall set the value of V( R) to the value of 38
(SEQ+ LEN) modulo 256. 39 30
30 Page 31 32
Ballot Version Proposed TIA/ EIA/ PN-3676.2
3-17
When the transparent RLP receives an idle frame from the multiplex sublayer, the 1
transparent RLP receiver shall discard the frame. 2

3.2.3 Frame Validity Checks 3
Transparent RLP shall discard as invalid all traffic channel frames received which are 4
classified into category 9 or 10 by Multiplex Option 1 (see 6.2.2.2 of TIA/ EIA/ IS-95). 5

Transparent RLP sublayer shall discard as invalid all traffic channel frames received which 6
are classified into category 26 by Multiplex Option 2 (see 6.2.2.2 of TIA/ EIA/ IS-95). 7

3.3 Traffic Channel Rate Control 8
The following requirements for traffic channel rate control shall apply to mobile stations 9
having a single connected service option. Traffic channel rate control for mobile stations 10
having multiple connected service options is for further study. 11

3.3.1 Service Option Negotiation Rate Control Procedures 12
The BS/ MSC may send a Service Option Control Order to the mobile station on the Forward 13
Traffic Channel (see 7.7.4 of TIA/ EIA/ IS-95-A). The mobile station shall not send Service 14
Option Control Orders for the purpose of rate control to the BS/ MSC. 15

If the mobile station receives a Service Option Control Order having an ORDQ field in which 16
the 3 MSBs have values given in Table 3.3.1-1, then the mobile station shall generate the 17
fraction P of those new traffic channel frames normally generated as full-rate frames at 18
either full rate (Rate 1) or half rate (Rate 1/ 2) as specified by the corresponding line in the 19
table. While the traffic channel is active the mobile station shall continue to use these 20
fractions until the mobile station receives a Service Option Control Order that specifies 21
different fractions. 22

Whenever a traffic channel first becomes active, the mobile station shall set the fraction P 23
to 1. 24

25

Table 3.3.1-1. Fraction of Frames at Rate 1 and Rate 1/ 2 with Rate Reduction 26

ORDQ
(binary)

P = Fraction of
Normally Rate 1 Frames
to be Rate 1

(1 -P) = Fraction of
Normally Rate 1 Frames
to be Rate 1/ 2

000XXXXX 1 0
001XXXXX 3/ 4 1/ 4
010XXXXX 1/ 2 1/ 2
011XXXXX 1/ 4 3/ 4
100XXXXX 0 1

27 31
31 Page 32 33
Proposed TIA/ EIA/ PN-3676.2 Ballot Version
3-18
The mobile station may use the following procedure to perform this rate reduction. 1
Sequences of N frames are formed as shown in Table 3.3.1-2. The first L traffic channel 2
frames in this sequence are allowed to be at Rate 1, the next N-L frames are forced to be 3
Rate 1/ 2. Whenever the RLP layer has no more octets to send than fit in a Rate 1/ 2 RLP 4
data frame, a Rate 1/ 2 RLP data frame shall be sent, and the sequence shall be reset. This 5
ensures that the first traffic channel frame in a burst of data will be at Rate 1, unless 6
ORDQ equals '100XXXXX' or the RLP layer has been commanded by the multiplex sublayer 7
to generate other than a Rate 1 frame. 8

9

Table 3.3.1-2. Sequence Parameters for Rate Reduction 10

ORDQ
(binary)
Sequence
Length, N

Maximum Number
of Contiguous
Rate 1 Frames in a
Sequence, L

Number of
Contiguous
Rate 1/ 2 Frames
in a Sequence, N-L

000XXXXX 1 1 0
001XXXXX 4 3 1
010XXXXX 2 1 1
011XXXXX 4 1 3
100XXXXX 1 0 1

11

3.3.2 Service Negotiation Rate Control Procedures 12
If service negotiation is used, the BS/ MSC may send a Service Option Control Message to 13
the mobile station on the Forward Traffic Channel (see 7.7.3.3 of TIA/ EIA/ TSB-74). The 14
mobile station shall not send a Service Option Control Message to the BS/ MSC. 15

3.3.2.1 Mobile Station Requirements 16
The mobile station shall support one pending rate control Service Option Control Message 17
for the service option. 18

If the mobile station receives a Service Option Control Message for the service option with 19
FIELD_ TYPE set to '000', then at the action time associated with the message, the mobile 20
station shall process the message as follows: 21

░ If the RATE_ REDUC field is equal to a value defined in Table 3.3.2.2-2, the service 22
option shall generate the fraction of those frames normally generated as Rate 1 23
frames at either Rate 1 or Rate 1/ 2 as specified by the corresponding line in 24
Table 3.3.2.2-2. The service option shall continue to use these fractions until either 25
of the following events occur: 26

-The mobile station receives a Service Option Control Message with FIELD_ TYPE 27
set to '000' specifying a different RATE_ REDUC, or 28

-The service option is re-initialized. 29 32
32 Page 33 34
Ballot Version Proposed TIA/ EIA/ PN-3676.2
3-19
░ If the RATE_ REDUC field is not equal to a value defined in Table 3.3.2.2-2, the 1
mobile station shall reject the message by sending a Mobile Station Reject Order with 2
the ORDQ field set equal to '00000100'. 3

The service option may use the following procedure to perform rate reduction. Sequences of 4
N frames are formed as shown in Table 3.3.2.1-1 are allowed to be at Rate 1, the next N-L 5
frames are forced to be Rate 1/ 2. Whenever the RLP layer has no more octets to send than 6
fit in a Rate 1/ 2 RLP data frame, a Rate 1/ 2 RLP data frame shall be sent, and the 7
sequence shall be reset. This ensures that the first Traffic Channel frame in a burst of data 8
will be at Rate 1, unless RATE_ REDUC equals '100' or the RLP layer has been commanded 9
by the multiplex sublayer to generate other than a Rate 1 frame. 10

11

Table 3.3.2.1-1. Sequence Parameters for Rate Reduction 12

RATE_ REDUC
(binary)
Sequence
Length, N

Maximum Number of
Contiguous Rate 1
Frames in a
Sequence, L

Number of
Contiguous Rate 1/ 2
Frames in a
Sequence, N-L

'000' 1 1 0
'001' 4 3 1
'010' 2 1 1
'011' 4 1 3
'100' 1 0 1

13

3.3.2.2 BS/ MSC Requirements 14
The BS/ MSC may send a Service Option Control Message to the mobile station for Traffic 15
Channel rate control. If the BS/ MSC sends a Service Option Control Message for Traffic 16
Channel rate control, the BS/ MSC shall include the type-specific fields shown in Table 17
3.3.2.2-1. 18

19

Table 3.3.2.2-1. Service Option Control Message Type-Specific Fields for Traffic 20
Channel Rate Control 21

Field Length (bits)
RATE_ REDUC 3
RESERVED 2
FIELD_ TYPE 3

22
RATE_ REDUC -Rate reduction. 23 33
33 Page 34 35
Proposed TIA/ EIA/ PN-3676.2 Ballot Version
3-20
The BS/ MSC shall set this field to the RATE_ REDUC value 1
from Table 3.3.2.2-2 corresponding to the rate reduction that 2
the mobile station is to perform. 3

RESERVED -Reserved bits. 4
The BS/ MSC shall set this field to '00'. 5
FIELD_ TYPE -Type-specific field designator. 6
The BS/ MSC shall set this field to '000'. 7

8

Table 3.3.2.2-2. Fraction of Frames at Rate 1 and Rate 1/ 2 with Rate Reduction 9

RATE_ REDUC
(binary)
Fraction of Normally
Rate 1 Frames to be
Rate 1

Fraction of Normally
Rate 1 Frames to be
Rate 1/ 2

'000' 1 0
'001' 3/ 4 1/ 4
'010' 1/ 2 1/ 2
'011' 1/ 4 3/ 4
'100' 0 1
All other RATE_ REDUC values are reserved.

10 34
34 Page 35 36
Ballot Version Proposed TIA/ EIA/ PN-3676.2
4-1
4 RLP FRAME FORMATS 1
4.1 Traffic Channel Frames for Non-Transparent RLP 2
Non-transparent RLP shall send and receive traffic channel frames in accordance with the 3
requirements of IS-95 Multiplex Options 1 and 2. 4

Non-transparent RLP frames can be transmitted as primary traffic or as secondary traffic. 5
Service options may support any subset of the available traffic types and RLP frame types 6
to carry non-transparent RLP. 7

Mobile stations supporting multiple connected service options may support independent 8
instances of non-transparent RLP for each service option, but each traffic type shall carry 9
only a single instance of non-transparent RLP. RLP data frames sent on one traffic type 10
shall not be retransmitted on another traffic type. 11

Non-transparent RLP frames shall not be sent on the Access and Paging Channels. 12
The frame formats defined in 4.3.1 through 4.3.3 can be carried by the following Multiplex 13
Option 1 frames (see 6.1.3.3.11 and 7.1.3.5.11 of TSB74): 14

░ 9600 bps primary traffic only (full rate primary traffic). 15
░ 4800 bps primary traffic only (half rate primary traffic). 16
░ Dim and Burst with Rate 1/ 2 primary and signaling traffic, as primary traffic. 17
░ Dim and Burst with Rate 1/ 2 primary and secondary traffic, either as primary traffic, 18
secondary traffic, or both. 12 19

░ Dim and Burst with Rate 1/ 4 primary and secondary traffic, as secondary traffic. 20
░ Dim and Burst with Rate 1/ 8 primary and secondary traffic, as secondary traffic. 21
░ Blank and burst with secondary traffic only. 22
The frame formats defined in 4.3.1 through 4.3.3 can be carried by the following Multiplex 23
Option 2 frame formats (see 6.1.3.3.12 and 7.1.3.5.12 of TSB74): 24

░ 14400 bps primary traffic only (full rate primary traffic). 25
░ 7200 bps primary traffic only (half rate primary traffic). 26
░ 3600 bps primary traffic only (quarter rate primary traffic). 27
░ 1800 bps primary traffic only (eighth rate primary traffic). 28
░ Dim and Burst with Rate 1/ 2 primary and signaling traffic, as primary traffic. 29

12 RLP would be carried as both primary and secondary traffic simultaneously if there are two service
options active (one using primary traffic and the other using secondary traffic), each with its own
instance of RLP. 35
35 Page 36 37
Proposed TIA/ EIA/ PN-3676.2 Ballot Version
4-2
░ Dim and Burst with Rate 1/ 2 primary and secondary traffic, as primary traffic, 1
secondary traffic, or both. 13 2

░ Dim and Burst with Rate 1/ 4 primary and secondary traffic, as primary traffic, 3
secondary traffic 14 , or both. 4

░ Dim and Burst with Rate 1/ 4 primary and signaling traffic, as primary traffic, 5
░ Dim and Burst with Rate 1/ 8 primary and signaling traffic, as primary traffic, 6
░ Dim and Burst with Rate 1/ 8 primary and secondary traffic, as primary traffic, 7
secondary traffic, or both, 8

░ Dim and Burst with Rate 1/ 8 primary, secondary, and signaling traffic, as primary 9
traffic, secondary traffic, or both, 10

░ Blank and burst with secondary traffic only. 11
For full rate primary traffic only, two special frame formats are defined in 4.3.2.3. The 12
information field of the first format corresponds to an RLP control or data frame as defined 13
in 4.3.1 and 4.3.2 respectively. The second frame format contains a sequence number and 14
user data only and allows maximum throughput. 15

4.2 Traffic Channel Frames for Transparent RLP 16
Transparent RLP shall send and receive traffic channel frames in accordance with the 17
requirements of IS-95 Multiplex Options 1 and 2. 18

Transparent RLP frames can be transmitted as primary traffic only. Service options may 19
support any subset of the RLP data frame types to carry transparent RLP. 20

Mobile stations supporting multiple connected service options may support a single 21
instance of Transparent RLP. Transparent RLP frames shall not be sent on the Access and 22
Paging Channels. 23

The frame formats defined in 4.3.2 below can be carried by the following Multiplex Option 1 24
frames (see 6.1.3.3.11 and 7.1.3.5.11 of TSB74): 25

░ 9600 bps primary traffic only as primary traffic. 26
░ 4800 bps primary traffic only as primary traffic. 27
░ Dim and Burst with Rate 1/ 2 primary and signaling traffic, as primary traffic. 28
░ Dim and Burst with Rate 1/ 2 primary and secondary traffic, as primary traffic. 29
░ Blank and burst with secondary traffic only. 30

13 RLP would be carried as both primary and secondary traffic simultaneously if there are two service
options active (one using primary traffic and the other using secondary traffic), each with its own
instance of RLP.

14 With the exception of the last segmented frame, Rate 1/ 4 RLP frames may not carry segmented RLP
data frames( see 3.1.4). 36
36 Page 37 38
Ballot Version Proposed TIA/ EIA/ PN-3676.2
4-3
The frame formats defined in 4.3.2 below can be carried by the following Multiplex Option 2 1
frames (see 6.1.3.3.12 and 7.1.3.5.12 of TSB74): 2

░ 14400 bps primary traffic only as primary traffic. 3
░ 7200 bps primary traffic only as primary traffic. 4
░ 3600 bps primary traffic only as primary traffic. 5
░ 1800 bps primary traffic only as primary traffic. 6
░ Dim and Burst with Rate 1/ 2 primary and signaling traffic, as primary traffic. 7
░ Dim and Burst with Rate 1/ 2 primary and secondary traffic, as primary traffic. 8
░ Dim and Burst with Rate 1/ 4 primary and signaling traffic, as primary traffic. 9
░ Dim and Burst with Rate 1/ 4 primary and secondary traffic, as primary traffic. 10
░ Dim and Burst with Rate 1/ 8 primary and signaling traffic, as primary traffic. 11
░ Dim and Burst with Rate 1/ 8 primary and secondary traffic, as primary traffic. 12
░ Dim and Burst with Rate 1/ 8 primary, secondary, and signaling traffic, as primary 13
traffic. 14

░ Blank and burst with secondary traffic only. 15
For full rate primary traffic only, transparent RLP may use the Full Rate Format B frame, as 16
defined in 4.3.2.3.2. 17

4.3 RLP Frame Formats 18
4.3.1 RLP Control Frames 19
RLP control frames are distinguished by the CTL field. 20
RLP control frames are not themselves sequence numbered, but contain the next data 21
sequence number, in order that erased RLP data frames may be quickly detected. The 22
sequence number is not incremented after an RLP control frame. 23

Certain RLP control frames (specifically the NAK message) may refer to the sequence 24
numbers of other RLP data frames. 25

26 37
37 Page 38 39
Proposed TIA/ EIA/ PN-3676.2 Ballot Version
4-4
Field Length (bits)
SEQ 8
CTL 8
FIRST 8
LAST 8
EM 0 or 2
EXT_ SEQ_ M 0 or 22
FCS 16
Padding Variable

1
SEQ -RLP data frame sequence number. See 3.1.2. 2
CTL -RLP frame type. For RLP control frames, the CTL field is 3
defined as follows: 4

'1100 0000' -NAK (negative acknowledgment). Requests 5
retransmission of RLP data frames numbered FIRST through 6
LAST, inclusive. 7

'1101 0000' -Non-Encrypted Mode SYNC. Requests return of 8
an RLP control frame with the ACK bit set. 9

'1101 0011' -Encrypted Mode SYNC. Requests return of an 10
RLP control frame with the ACK bit set. 11

'1110 0000' -Non-Encrypted Mode ACK. Acknowledges 12
receipt of an RLP control frame with the SYNC bit set. 13

'1110 0011' -Encrypted Mode ACK. Acknowledges receipt of 14
an RLP control frame with the SYNC bit set. 15

'1111 0000' -Non-Encrypted Mode SYNC/ ACK. Indicates 16
both SYNC and ACK. 17

'1111 0011' -Encrypted Mode SYNC/ ACK. Indicates both 18
SYNC and ACK. 19

FIRST -For NAK RLP control frames, the FIRST field shall contain the 20
sequence number of the first RLP data frame for which 21
retransmission is requested. For all other RLP control frame 22
types, this field shall contain 0x00. 23

LAST -For NAK RLP control frames, the LAST field shall contain the 24
sequence number of the last RLP data frame for which 25
retransmission is requested. For all other RLP control frame 26
types, this field shall contain 0x00. 27

EM -Encryption Mode. 28
This field shall be included in Encrypted Mode SYNC, 29
SYNC/ ACK and ACK RLP control frames. This field shall not 30
be included in NAK RLP control frames or in Non-Encrypted 31
mode RLP control frames. 32 38
38 Page 39 40
Ballot Version Proposed TIA/ EIA/ PN-3676.2
4-5
'00' (Default) Requests or Acknowledges no RLP data frame 1
encryption (not supported or inactive). 2

'01' Requests or Acknowledges RLP data frame encryption 3
capability. 4

EXT_ SEQ_ M -This field shall be included in Encrypted Mode SYNC, 5
SYNC/ ACK and ACK RLP control frames. This field shall not 6
be included in NAK RLP control frames. 7

When the EM field is set to '01', this field shall carry the most 8
significant bits of the extended data frame sequence number. 9
Otherwise, this field shall be set to all zeros. 10

When included, contents of this field shall be set to the 22 11
most significant bits of EXT_ V( S) (see 3.1.1.2.2). 12

FCS -Frame Check Sequence. The contents shall be as generated 13
by the 16-bit FCS polynomial specified in 3.1 of RFC 1662. 14
The FCS shall cover the SEQ, CTL, FIRST, LAST, EM (if 15
included), and EXT_ SEQ_ M (if included) fields. 16

Padding -Padding bits. As required to fill the remainder of the frame. 17
These bits shall be set to '0'. 18

19

4.3.2 RLP Data Frames 20
4.3.2.1 Unsegmented RLP Data Frames 21
Unsegmented RLP data frames carry a variable number of data octets, using a length field 22
to indicate the number of octets. 23

24
Field Length (bits)

SEQ 8
CTL 1
LEN 7
Data 8xLEN
Padding Variable

25
SEQ -RLP data frame sequence number. See 3.1.2. 26
CTL -RLP frame type. For a frame carrying unsegmented data the 27
CTL field shall be set to '0'. 15 28

15 Note that the most significant bit of the CTL field of a control frame and a segmented data frame is
always set to '1'. 39
39 Page 40 41
Proposed TIA/ EIA/ PN-3676.2 Ballot Version
4-6
LEN -Data length. May be any value in the range from 0 to the 1
maximum allowable for the RLP frame. Maximum values of 2
LEN (MAX_ LEN) are as given in Table 4.3.2.1-1. 3

When LEN is zero, the RLP frame is treated as an RLP idle 4
frame, and the sequence number is not advanced. 5

Data -Data octets. 6
Padding -Padding bits. As required to fill the remainder of the frame. 7
These bits shall be set to '0'. 8

9

Table 4.3.2.1-1. Values of the Maximum Allowable Data Length (MAX_ LEN) 10

Traffic Type
MAX_ LEN
Multiplex
Option 1

MAX_ LEN
Multiplex
Option 2

Primary Traffic
Rate 1/ 4 Not Used 4
Rate 1/ 2 8 13
Full rate (see 4.3.2.3) 19 31
Secondary Traffic
With Rate 1/ 2 primary traffic 9 15
With Rate 1/ 4 primary traffic 14 23
With Rate 1/ 8 primary traffic 17 28
Blank and burst 19 30

11

4.3.2.2 Segmented RLP Data Frames 12
Segmented RLP data frames carry a variable number of data octets, using a length field to 13
indicate the number of octets. This type of data frame shall be used only to carry 14
retransmitted RLP data frames (see 3.1.4). 15

16
Field Length (bits)

SEQ 8
CTL 4
LEN 0 or 4
Data 0 or 8xLEN
Padding Variable

17
SEQ -RLP data frame sequence number. See 3.1.2. 18 40
40 Page 41 42
Ballot Version Proposed TIA/ EIA/ PN-3676.2
4-7
CTL -RLP frame type. For segmented RLP data frames, the CTL 1
field is defined as follows: 2

'1000' -First Segment. Contains the first LEN octets of the 3
segmented RLP data frame. 4

'1001' -Second Segment. Contains the next LEN octets of the 5
segmented RLP data frame. 6

'1010' -Last Segment. Contains the last LEN octets of the 7
segmented RLP data frame. 8

'1011' -RLP Intersegment Fill Frame. When Multiplex Option 9
2 is used, RLP Intersegment Fill Frames can be sent before or 10
between segmented RLP data frames (see 3.1.4). RLP 11
Intersegment Fill Frames are not used for Multiplex Option 1. 12

LEN -Data length. When CTL is set to '' 1000', '1001', or '1010', the 13
LEN field may be any value in the range from 1 to the 14
maximum allowable for the RLP frame, or 15, whichever is 15
less. Values of the maximum allowable data length 16
(MAX_ LEN) are as given in Table 4.3.2.1-1. When CTL is set 17
to '1011' the LEN field shall not be included. 18

Data -Data octets. When CTL is set to '1000', '1001', or '1010', this 19
field shall carry LEN Data octets. When CTL is set to '1011' 20
the Data field shall not be included 21

Padding -Padding bits. As required to fill the remainder of the frame. 22
These bits shall be set to '0'. 23

4.3.2.2.1 Rate 1/ 8 and Rate 1/ 16 Intersegment Fill Frames 24
For Multiplex Option 2, Rate 1/ 8 primary traffic RLP frames and Rate 1/ 16 secondary 25
traffic RLP frames may be Intersegment Fill frames. 26

27
Field Length (bits)

SEQ 8
FCS 8
ISF 4

28
SEQ -RLP data frame sequence number. See 3.1.4. 29
FCS -Frame Check Sequence. This field is identical to the FCS field 30
of an RLP idle frame with matching SEQ field. See 4.3.3. 31

ISF -Intersegment Fill frame indicator. The value '1111' indicates 32
an Intersegment Fill frame. 33

4.3.2.3 Primary Traffic 34
For RLP frames carried on full rate primary traffic frames, two special frame formats 35
described in 4.3.2.3.1 and 4.3.2.3.2 shall be used. For RLP frames carried on half-rate or 36 41
41 Page 42 43
Proposed TIA/ EIA/ PN-3676.2 Ballot Version
4-8
quarter rate frames, RLP data frames or RLP control frames, as defined in 4.3.2 and 1
4.3.2.1, apply directly. 2

4.3.2.3.1 Full Rate Format A 3
IS-95 full rate primary traffic frames of format A can carry either RLP data frames or RLP 4
control frames, as defined in 4.3.1 and 4.3.2. 5

For Multiplex Option 1, full rate format A frames are defined as follows: 6
7
Field Length (bits)

Information 168
TYPE 3

8
Information -RLP control or data frame. Formatted according to the RLP 9
control and data frames described in 4.3.1 and 4.3.2.1. 10

TYPE -Frame type. The TYPE field shall be set to '001'. 11

12

For Multiplex Option 2, full rate format A frames are defined as follows: 13
14
Field Length (bits)

Information 264
TYPE 2

15
Information -RLP control or data frame. Formatted according to the RLP 16
control and data frames described in 4.3.1 and 4.3.2.1. 17

TYPE -Frame type. The TYPE field shall be set to '01'. 18

19

4.3.2.3.2 Full Rate Format B 20
For Multiplex Option 1, format B carries 20 octets of data, as follows: 21
22
Field Length (bits)

SEQ 8
Data 160
TYPE 3

23
SEQ -Frame sequence number. See 3.1.2. 24 42
42 Page 43 44
Ballot Version Proposed TIA/ EIA/ PN-3676.2
4-9
Data -Data octets. This field shall contain 20 octets of data. 1
TYPE -Frame type. The TYPE field shall be set to '010'. 2

For Multiplex Option 2, format B carries 32 octets of data, as follows: 3
4
Field Length (bits)

SEQ 8
Data 256
TYPE 2

5
SEQ -Frame sequence number. See 3.1.2. 6
Data -Data octets. This field shall contain 32 octets of data. 7
TYPE -Frame type. The TYPE field shall be set to '10'. 8

9

4.3.3 RLP Idle Frames 10
For Multiplex Option 1, Rate 1/ 8 RLP frames are RLP idle frames. For Multiplex Option 2, 11
Rate 1/ 8 primary traffic RLP frames and Rate 1/ 16 secondary traffic RLP frames may be 12
RLP idle frames. Higher rate RLP data frames with zero length (LEN = 0) (see 4.3.2.1) are 13
also RLP idle frames, and may be sent as an alternative. 14

15
Field Length (bits)

SEQ 8
FCS 8
Padding 0 or 4

16
SEQ -RLP frame sequence number. This field is set to the current 17
value of V( S) (see 3.1.2.1 and 3.2.2). 18

FCS -Frame Check Sequence based on a modified 19
Nordstrom-Robinson code. 20

Let the sequence number to be coded be denoted as 21
X 7 X 6 X 5 X 4 X 3 X 2 X 1 X 0 ( ) 22

Let the FCS be denoted as 23
Y 7 Y 6 Y 5 Y 4 Y 3 Y 2 Y 1 Y 0 ( ) 24

The FCS is generated as follows: 25 43
43 Page 44 45
Proposed TIA/ EIA/ PN-3676.2 Ballot Version
4-10
Y 0 = X 7 ┼ X 6 ┼ X 0 ┼ X 1 ┼ X 3 ┼
X 0 ┼ X 4 ( )ÎX 1 ┼X 2 ┼X 3 ┼X 5 ( )┼
X 1 ┼X 2 ( )ÎX 3 ┼X 5 ( ) 1
Where ┼ denotes modulo-2 addition. Code bits Y 1 through 2
Y 6 are found by cyclically shifting X 0 through X 6 . In other 3
words, X i + j ( )mod 7 is substituted for X i in the generating 4

equation for Y j . Y 7 is a parity bit over the previous 15 bits. 5
The final step in generating the FCS is to complement the last 6
three bits. A table specifying the code is provided in Table 7
4.3.3-1. 8

Pad -Padding bits. As required to fill the remainder of the frame. 9
These bits shall be set to '0'. 10

Table 4.3.3-1 presents the modified Nordstromđ Robinson code used to protect Rate 1/ 8 and 11
Rate 1/ 16 RLP idle frames. In Table 4.3.3-1, the most significant byte in a word is the SEQ 12
value to be protected and the least significant byte is the FCS. All numbers are 13
hexadecimal. 14

15 44
44 Page 45 46
Ballot Version Proposed TIA/ EIA/ PN-3676.2
4-11
1
Table 4.3.3-1. Modified Nordstromđ Robinson Code 2

0007 20f3 40ee 6034 8078 a08c c091 e04b 3
01d4 2119 4161 6182 81ab a166 c11e e1fd 4
02a0 226d 423b 62d8 82df a212 c244 e2a7 5
034a 23be 438d 6357 8335 a3c1 c3f2 e328 6
04c9 242a 4452 649f 84b6 a455 c42d e4e0 7
057f 25a5 45b8 654c 8500 a5da c5c7 e533 8
061c 26c6 46f5 6601 8663 a6b9 c68a e67e 9
0793 2770 4726 67eb 87ec a70f c759 e794 10
089a 2840 485d 68a9 88e5 a83f c822 e8d6 11
092c 29cf 49b7 697a 8953 a9b0 c9c8 e905 12
0a76 2a95 4ac3 6a0e 8a09 aaea cabc ea71 13
0bf9 2b23 4b10 6be4 8b86 ab5c cb6f eb9b 14
0c31 2cfc 4c84 6c67 8c4e ac83 ccfb ec18 15
0de2 2d16 4d0b 6dd1 8d9d ad69 cd74 edae 16
0eaf 2e5b 4e68 6eb2 8ed0 ae24 ce17 eecd 17
0f45 2f88 4fde 6f3d 8f3a aff7 cfa1 ef42 18
10bd 305e 5008 70c5 90c2 b021 d077 f0ba 19
1132 31e8 51db 712f 914d b197 d1a4 f150 20
1251 328b 5296 7262 922e b2f4 d2e9 f21d 21
13e7 3304 537c 73b1 9398 b37b d303 f3ce 22
1464 3490 54a3 7479 941b b4ef d4dc f406 23
158e 3543 5515 75f6 95f1 b53c d56a f589 24
16fa 3637 564f 76ac 9685 b648 d630 f6d3 25
1729 37dd 57c0 771a 9756 b7a2 d7bf f765 26
186b 38a6 58f0 7813 9814 b8d9 d88f f86c 27
1981 3975 5946 799c 99fe b90a d939 f9e3 28
1acc 3a38 5a25 7aff 9ab3 ba47 da5a fa80 29
1b1f 3bd2 5baa 7b49 9b60 bbad dbd5 fb36 30
1cd7 3c0d 5c3e 7cca 9ca8 bc72 dc41 fcb5 31
1d58 3dbb 5ded 7d20 9d27 bdc4 dd92 fd5f 32
1e02 3ee1 5e99 7e54 9e7d be9e dee6 fe2b 33
1fb4 3f6e 5f73 7f87 9fcb bf11 df0c fff8 34 45
45 Page 46
Proposed TIA/ EIA/ PN-3676.2 Ballot Version
4-12
1
No text. 2 46

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