CONTENTS

1 Scope
2 References
3 Terms and definitions
4 Abbreviations
5 Conventions
6 Description of the DTE/DCE interface (physical layer)
6.1 ITU-T X.21 interface
6.1.1 DTE/DCE interface element
6.1.2 Procedures for entering operational phases
6.1.3 Failure detection and test loops
6.1.4 Signal element timing
6.2 X.21bis interface
6.2.1 DTE/DCE physical interface elements
6.2.2 Operational phases
6.2.3 Failure detection and test loops
6.2.4 Signal element timing
6.3 V-series interfaces
6.4 G-series interfaces
6.5 I-series interfaces
7 Description of services
7.1 General definition
7.2 Multiplexing
7.3 Service aspect
7.4 Frame transfer priority
7.4.1 General description
7.4.2 Service provisioning and request
7.5 Frame discard priority
7.5.1 General description
7.5.2 Service Provisioning and Signalling
7.5.3 Frame Discard Priority and Other Frame Relay Parameters
7.6 Frame Relay Service Class
7.7 Support of both Service Class and Priorities
7.8 SVC related services
8 Service parameters and Service quality
8.1 Scope
8.2 Service parameters
8.2.1 Access Rate (AR)
8.2.2 Committed Burst Size (Bc)
8.2.3 Excess Burst Size (Be)
8.2.4 Committed Information Rate (CIR)
8.2.5 Committed Rate Measurement Interval (Tc)
8.2.6 Maximum octet length of Frame Relay Information Field (N203)
8.2.7 Priorities or service Class
8.2.8 Fragmentation parameters
8.3 SVC related service parameters
8.3.1 DTE address
8.3.2 Maximum number of SVCs
8.3.3 Default values for Link Layer Core Parameters
8.3.4 CUG profile
8.3.5 Reverse charging prevention
8.3.6 Default priorities
8.3.7 Priorities versus Service Class
8.4 Service quality
9 Data link transfer control
9.1 General
9.2 Frame format
9.2.1 Flag sequence
9.2.2 Address field
9.2.3 Information field
9.2.4 Frame Check Sequence (FCS) field
9.3 Addressing
9.3.1 General
9.3.2 Address field format
9.3.3 The address field element
9.4 Transmission consideration
9.4.1 Order of bit transmission
9.4.2 Order of bits in frame fields
9.4.3 Transparency
9.4.4 Inter frame fill
9.4.5 Invalid frame
9.4.6 Frame abortion
9.5 Frame Relay Data Transmission Service over SDH
9.5.1 General aspects
9.5.2 Framing aspects
9.6 Fragmentation
9.6.1 Fragmentation Format
9.6.2 Fragmentation Procedures
9.6.3 Reassembly Procedures
9.6.4 Example of operation
10 Call connection control
10.1 General
10.2 Signalling channel
10.3 List of the signalling channel link layer parameters
10.4 Call states
10.4.1 Call states at the DTE side
10.4.2 Call states at the DCE side
10.4.3 States used with the restart facility
10.5 Message definitions
10.5.1 CALL PROCEEDING
10.5.2 CONNECT
10.5.3 DISCONNECT
10.5.4 RELEASE
10.5.5 RELEASE COMPLETE
10.5.6 RESTART
10.5.7 RESTART ACKNOWLEDGE
10.5.8 SETUP
10.5.9 STATUS
10.5.10 STATUS ENQUIRY
10.6 General message format and information element coding
10.6.1 Protocol discriminator
10.6.2 Call reference
10.6.3 Message type
10.6.4 Bearer capability
10.6.5 Call state
10.6.6 Called party number
10.6.7 Called party subaddress
10.6.8 Calling party number
10.6.9 Calling party subaddress
10.6.10 Cause
10.6.11 Closed user group
10.6.12 Connected number
10.6.13 Connected subaddress
10.6.14 Data link connection identifier
10.6.15 Link layer core parameters
10.6.16 Link layer protocol parameters
10.6.17 Low layer compatibility
10.6.18 Priority and service class parameters information element
10.6.19 Reverse charging indication
10.6.20 Transit network selection
10.6.21 User-user
10.7 Call establishment and clearing procedures
10.7.1 Call establishment at the calling DTE/DCE interface
10.7.2 Call establishment at the called DTE/DCE interface
10.7.3 Frame relay data transfer phase
10.7.4 Call clearing
10.8 Status enquiry and status procedures
10.8.1 Status enquiry procedure
10.8.2 Receiving a STATUS message
10.8.3 Receipt of the STATUS message with the global call reference
10.9 Restart procedure
10.9.1 Sending a RESTART message
10.9.2 Receipt of a RESTART message
10.10 Handling of error conditions
10.10.1 Protocol discriminator error
10.10.2 Message too short
10.10.3 Call reference error
10.10.4 Message type or message sequence errors
10.10.5 General information element errors
10.10.6 Mandatory information element errors
10.10.7 Non-mandatory information element errors
10.10.8 Handling of data link exceptions of the signalling channel
10.11 List of timers
10.11.1 DTE timers
10.11.2 DCE timers
10.12 Closed user group facility
10.12.1 General
10.12.2 Subscription options
10.12.3 Per call options
10.12.4 Simple CUG
10.12.5 CUG selection
10.12.6 No CUG
10.13 Transit network selection facility
10.14 Reverse charging facility
10.14.1 Reverse charging request and acceptance
10.14.2 Reverse charging prevention
10.15 Frame Transfer priority
10.15.1 Actions by the calling DTE
10.15.2 Actions by the network
10.15.3 Actions by the called DTE
10.16 Frame Discard priority
10.16.1 Actions by the Calling DTE
10.16.2 Actions by the Network
10.16.3 Actions by the Called DTE
10.17 Frame Relay Service Class
10.17.1 Action by the calling DTE
10.17.2 Action by the network
10.17.3 Action by the called DTE
10.18 Support of both Service Class and Priorities
10.18.1 Action by the calling DTE
10.18.2 Action by the network
10.18.3 Action by the called DTE
10.19 Charging information
11 PVC management procedures
11.1 Overview
11.2 Message definition
11.2.1 STATUS ENQUIRY message
11.2.2 STATUS message
11.3 Message specific information elements
11.3.1 Message type
11.3.2 Report type
11.3.3 Link integrity verification
11.3.4 PVC status
11.4 Description of procedures
11.4.1 Periodic Polling
11.4.2 Asynchronous PVC STATUS message
11.5 Optional bidirectional network procedures
11.6 System parameters
12 Congestion control
12.1 General
12.2 Impact of congestion
12.3 Congestion notification
12.3.1 Forward explicit congestion notification
12.3.2 Backward explicit congestion notification
12.4 DTE congestion detection method and actions
Annex A List and status of the X.36 parameters
Annex B Functional support at the DTE/DCE interface
B.1 Protocol Capabilities (PC)
B.2 Frames protocol data units (FR)
B.3 System Parameters (SP)
Annex C Consolidated Link Layer Management (CLLM) message
C.1 Address octets
C.2 Control field
C.3 XID information field
C.3.1 Format identifier field
C.3.2 Group field
C.3.3 Parameter set identification parameter
C.3.4 Cause identifier parameter field
C.3.5 DLCI identifier parameter field
C.4 FCS field
C.5 Network CLLM message transmission procedure
C.5.1 Network congestion
C.5.2 Network failure
C.5.3 Notification of network maintenance action
C.5.4 Recovery from cause given in the CLLM message
Annex D Use of frame relay for multiprotocol encapsulation
D.1 General frame format
D.2 Frame format for ISO CLNP (ISO/IEC 8473)
D.3 Frame format for IP
D.4 Frame Format for protocols with Ethertype code point
D.5 Frame format for bridged packets
D.5.1 Frame format for bridged 802.3 frame
D.5.2 Frame format for bridged 802.4 frame
D.5.3 Frame format for bridged 802.5 frame
D.5.4 Frame format for bridged FDDI frame
D.5.5 Frame format for bridged 802.6 frame
D.5.6 Frame format for Bridged PDU
D.5.7 Frame format for Source Routing Bridged PDU
D.5.8 Other protocols
D.5.9 Fragmentation issues
D.6 Low layer compatibility negotiation procedures
D.6.1 General purpose
D.6.2 Low layer capability notification to the called user
D.6.3 Low layer compatibility negotiation between users
D.6.4 Backward compatibility considerations
D.7 Examples
D.8 Protocol encapsulation format
D.8.1 Multiprotocol encapsulation format
D.8.2 Mono encapsulation format
Annex E Usage of Cause and Location
E.1 Location field generation
E.2 Cause values
E.3 Coding of the diagnostic field
E.3.1 Coding of condition
E.3.2 Coding of Transit network identity
E.3.3 Coding of call rejected diagnostic
E.3.4 Coding of timer value
E.3.5 Coding of message type
E.3.6 Coding of the facility type
Annex F Use of NSAP at the DTE-DCE interface
F.1 Introduction
F.2 Encoding of X.121 numbers as NSAP
F.3 Encoding of E.164 numbers as NSAP
F.4 Other ATM End System Address coding
Annex G Enhancements to PVC management procedures
G.1 Introduction
G.2 List of changes to clause 11
G.2.1 Clause 11.3.2 Report type
G.2.2 Procedures
G.2.3 Bidirectional procedures
Appendix I Examples of PVC management error events
I.1 Loss of STATUS ENQUIRY message
I.2 Loss of STATUS message
I.3 Invalid Receive Sequence Number
Appendix II DTE congestion detection methods and actions
II.1 Implicit congestion detection
II.2 Explicit congestion detection
Appendix III Handling of physical layer loopback conditions when using frame relay PVC bidirectional procedures
III.1 Recommended procedures for DTE/DCE that can detect loopback at the physical layer
III.2 Recommended procedures for DTE/DCE that cannot detect loopback at the physical layer
Appendix IV Information on address
IV.1 Main address and complementary address
IV.1.1 Main address
IV.1.2 Complementary address
IV.2 Addresses in SETUP message
IV.3 Addresses in CONNECT message
IV.4 Addresses processing by the network in SETUP message
IV.5 Addresses processing by the network in CONNECT message
Appendix V International network identification according to ITU-T X.125 for networks providing frame relay services and numbered under the E.164 numbering plan
V.1 Introduction
V.2 Assignment and notification process
Appendix VI Call state diagrams at the DCE side of the DTE/DCE interface and DCE actions
VI.1 Foreword
VI.2 Symbol definition of the call state diagrams
VI.3 Call state diagrams
VI.4 Actions taken by the DCE on receipt of message in a given call state at the DCE side of the DTE/DCE interface