📄 rfc3094.txt
字号:
Network Working Group D. Sprague
Request for Comments: 3094 R. Benedyk
Category: Informational D. Brendes
J. Keller
Tekelec
April 2001
Tekelec's Transport Adapter Layer Interface
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved.
IESG Note:
Readers should note that this memo presents a vendor's alternative to
standards track technology being developed by the IETF SIGTRAN
Working Group. The technology presented in this memo has not been
reviewed by the IETF for its technical soundness or completeness.
Potential users of this type of technology are urged to examine the
SIGTRAN work before deciding to use the technology described here.
Abstract
This document proposes the interfaces of a Signaling Gateway, which
provides interworking between the Switched Circuit Network (SCN) and
an IP network. Since the Gateway is the central point of signaling
information, not only does it provide transportation of signaling
from one network to another, but it can also provide additional
functions such as protocol translation, security screening, routing
information, and seamless access to Intelligent Network (IN) services
on both networks.
The Transport Adapter Layer Interface (TALI) is the proposed
interface, which provides TCAP (Transaction Capability Application
Part), ISUP (ISDN User Part), and MTP (Mail Transport Protocol)
messaging over TCP/IP. In addition, TALI provides SCCP (Signalling
Connection Control Part) Management (SCMG), MTP Primitives, dynamic
registration of circuits, and routing of call control messages based
on circuit location.
Sprague, et al. Informational [Page 1]
RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001
Table of Contents
1. Introduction 4
2. Overview of the TALI Protocol 6
2.1 Traditional PSTN SS7 Networks 6
2.2 Converged SS7 Networks 8
2.3 TALI Protocol Stack Overview 10
2.3.1 An Alternate TALI Protocol Stack using the SAAL Layer 13
2.3.2 An Alternate TALI Protocol Stack using SCTP 15
2.4 Inputs to the TALI Version 1.0 State Machine 15
3. TALI Version 1.0 17
3.1 Overview of the TALI Message Structure 17
3.1.1 Types of TALI Fields 19
3.2 Detailed TALI Message Structure 20
3.2.1 TALI Peer to Peer Messages 20
3.2.1.1 Test Message (test) 20
3.2.1.2 Allow Message (allo) 21
3.2.1.3 Prohibit Message (proh) 21
3.2.1.4 Prohibit Acknowledgement Message (proa) 21
3.2.1.5 Monitor Message (moni) 22
3.2.1.6 Monitor Acknowledge Message (mona) 22
3.2.2 Service Messages 23
3.2.2.1 SCCP Service Message (sccp) 23
3.2.2.1.1 SCCP Encapsulation using TALI 25
3.2.2.2 ISUP Service Message (isot) 27
3.2.2.2.1 ISUP Encapsulation using TALI 27
3.2.2.3 MTP3 Service Message (mtp3) 28
3.2.2.3.1 MTP3 Encapsulation using TALI 29
3.2.2.4 SAAL Service Message (saal) 30
3.2.2.4.1 MTP3 and SAAL Peer to Peer Encapsulation using TALI 31
3.3 TALI Timers 34
3.3.1 T1 Timer 34
3.3.2 T2 Timer 34
3.3.3 T3 Timer 34
3.3.4 T4 Timer 34
3.3.5 Recommended Defaults and Ranges for the TALI Timers 35
3.4 TALI User Events 35
3.4.1 Management Open Socket Event 35
3.4.2 Management Close Socket Event 36
3.4.3 Management Allow Traffic Event 36
3.4.4 Management Prohibit Traffic Event 36
3.5 Other Implementation Dependent TALI Events 37
3.6 TALI States 37
3.7 TALI Version 1.0 State Machine 38
3.7.1 State Machine Concepts 38
3.7.1.1 General Protocol Rules 38
3.7.1.2 Graceful Shutdown of a Socket 39
3.7.1.3 TALI Protocol Violations 39
Sprague, et al. Informational [Page 2]
RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001
3.7.2 The State Machine 40
3.8 TALI 1.0 Implementation Notes 42
3.8.1 Failure on a TCP/IP Socket 42
3.8.2 Congestion on a TCP/IP Socket 43
3.9 TALI 1.0 Limitations 43
4. TALI Version 2.0 43
4.1 Overview of TALI Version 2.0 Features 45
4.2 TALI Version Identification 47
4.3 Backwards Compatibility 50
4.3.1 Generating Protocol Violations based on Received Messages 53
4.4 Overview of the TALI Message Structure 55
4.4.1 Types of TALI Fields 55
4.5 Detailed TALI Message Structures for New 2.0 Opcodes 58
4.5.1 Management Message (mgmt) 60
4.5.1.1 Routing Key Registration Primitive (rkrp) 61
4.5.1.1.1 RKRP Data Structures 65
4.5.1.1.1.1 Common Fields in all RKRP Messages 65
4.5.1.1.1.2 CIC Based Routing Key Operations 67
4.5.1.1.1.3 SCCP Routing Key Operations 71
4.5.1.1.1.4 DPC-SI, DPC and SI based Routing Key Operations 74
4.5.1.1.1.5 Default Routing Key Operations 76
4.5.1.1.1.6 Support for Multiple RKRP Registration Operations 78
4.5.1.1.1.6.1 Multiple Registrations Support 78
4.5.1.1.1.6.2 Multiple RKRP Operations in a Single Message 80
4.5.1.2 MTP3 Primitive (mtpp) 82
4.5.1.3 Socket Option Registration Primitive (sorp) 87
4.5.2 Extended Service Message (xsrv) 91
4.5.3 Special Message (spcl) 92
4.5.3.1 Special Messages Not Supported (smns) 93
4.5.3.2 Query Message (qury) 93
4.5.3.3 Reply Message (rply) 94
4.5.3.4 Unsolicited Information Message (USIM) 95
4.6 TALI Timers 95
4.7 TALI User Events 95
4.8 TALI States 96
4.9 TALI Version 2.0 State Machine 96
4.9.1 State Machine Concepts 96
4.9.1.1 General Protocol Rules 96
4.9.1.2 Graceful Shutdown of a Socket 97
4.9.1.3 TALI Protocol Violations 97
4.9.2 The State Machine 97
4.10 TALI 2.0 Specification Limitations 101
5. Success/Failure Codes 101
6. Security Considerations 102
7. References 102
8. Acknowledgments 103
9. Authors' Addresses 104
10. Full Copyright Statement 105
Sprague, et al. Informational [Page 3]
RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001
1. Introduction
This document is organized into the following 6 sections:
- Introduction to the document
- Overview of the TALI Protocol
- TALI Version 1.0
- TALI Version 2.0
- Success/Failure Codes
- Security Considerations
The following terms are used throughout this document.
Circuit Identification Code (CIC):
A field identifying the circuit being setup or released. Depending
on SI and MSU Type, this field can be 12, 14 or 32 bits.
Changeover/Changeback (co/cb):
SS7 MTP3 procedure related to link failure and re-establishment.
Far End (FE):
The remote endpoint of a socket connection.
Far End Allowed (FEA):
The FE is ready to use the socket for service PDUs.
Far End Prohibited (FEP):
The FE is not ready to use the socket for service PDUs.
Intelligent Network (IN):
A network that allows functionality to be distributed flexibly at a
variety of nodes on and off the network and allows the architecture
to be modified to control the services.
Management ATM Adaptation Layer (MAAL):
This layer is a component of SAAL. This layer maps requests and
indications between the System Management for the SG and the other
SAAL layers. MAAL includes interfaces to/from SSCOP, SSCF, and
system management. More information can be found in T1.652.
Media Gateway (MG):
A MG terminates SCN media streams, packetizes the media data, if it
is not already packetized, and delivers packetized traffic to the
packet network. It performs these functions in reverse order for
media streams flowing from the packet network to the SCN.
Sprague, et al. Informational [Page 4]
RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001
Media Gateway Controller (MGC):
An MGC handles the registration and management of resources at the
MG. The MGC may have the ability to authorize resource usage based
on local policy. For signaling transport purposes, the MGC serves as
a possible termination and origination point for SCN application
protocols, such as SS7 ISDN User Part and Q.931/DSS1.
MTP3 Framing (MTP3F):
TALI does not require full MTP3 procedures support but rather uses
the MTP3 framing structure (ie: SIO, Routing Label, etc)
Near End (NE):
The local endpoint of a socket connection.
Near End Allowed (NEA):
The NE is ready to use the socket for service PDUs.
Near End Prohibited (NEP):
The NE is not ready to use the socket for service PDUs.
Q.BICC ISUP:
An ISUP+ variant that uses 32 bit CIC codes instead of 14/12 bit CIC
codes. ISUP+, or Q.BICC ISUP, is based on the Q.765.BICC
specification currently being developed in ITU Study Group 11.
Signaling ATM Adaptation Layer (SAAL):
This layer is the equivalent of MTP-2 for ATM High Speed Links
carrying SS7 Traffic as described in GR-2878-CORE [8]. SAAL includes
SSCF, SSCOP and MAAL.
Signaling Gateway (SG):
An SG is a signaling agent that receives/sends SCN native signaling
at the edge of the IP network. The SG function may relay, translate
or terminate SS7 signaling in an SS7-Internet Gateway. The SG
function may also be co-resident with the MGC/MG functions to process
SCN signaling associated with line or trunk terminations controlled
by the MG (e.g., signaling backhaul).
Service Specific Coordination Function (SSCF):
This layer is a component of SAAL. This layer maps the services
provided by the lower layers of the SAAL to the needs of a specific
higher layer user. In the case of the STP, the higher layer user is
the MTP-3 protocol, and the SSCF required is that as defined by
T1.645: SSCF for Support of Signaling at the Network Node Interface
(SSCF at the NNI). More information can be found in T1.645. SSCF
provides the interface between SSCOP and MTP3 and includes the
following functions:
Sprague, et al. Informational [Page 5]
RFC 3094 Tekelec's Transport Adapter Layer Interface April 2001
- Local Retrieve of messages to support link changeover procedures
- Flow control with four levels of congestion
Switched Circuit Network (SCN):
The term SCN is used to refer to a network that carries traffic
within channelized bearers of pre-defined sizes. Examples include
Public Switched Telephone Networks (PSTNs) and Public Land Mobile
Networks (PLMNs). Examples of signaling protocols used in SCN
include Q.931, SS7 MTP Level 3 and SS7 Application/User parts.
Service Specific Connection Oriented Protocol (SSCOP):
This layer is a component of SAAL. This layer provides reliable
point to point data transfer with sequence integrity and error
recovery by selective retransmission. Protocol layer interfaces are
described in T1.637. Aspects of the protocol include flow control,
connection control, error reporting to layer management, connection
maintenance in the prolonged absence of data transfer, local data
retrieval by the user of the SSCOP, error detection of protocol
control information and status reporting. SSCOP provides the link
layer functions that are:
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -