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Cisco BTS 10200 Softswitch

Release 4.2 SIP-T Feature Module

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Release 4.2 SIP-T Feature Module

Table Of Contents

Release 4.2 SIP-T Feature Module

Release 4.2 SIP-T Requirement

The SIP-T Protocol

New and Modified Tables

New Tables

SIPT-ISUP-VER-BASE Table

SIPT-ISUP-VER-ALIAS Table

Modified Tables

SOFTSW-TG-PROFILE Table

Rules

Upgrade Rules

CPM

What to Provision

When to Provision

DBM


Release 4.2 SIP-T Feature Module


For Release 4.2, Cisco BTS 10200 added the ability to carry different ISUP variants within a SIP-T message.

SIP-T is used to interconnect two Softswitches (such as the Cisco BTS 10200). In the embedded ISUP, SIP-T carries additional information that may not be available in the SIP headers. This allows for implementing ISUP- based features between two Softswitches when the originating and terminating ends of the call are in the PSTN (SS7/ISUP based).

However, using SIP-T for communication between two Cisco BTS 10200 nodes is independent of the originating and terminating protocol. The originator or terminator do not have to be ISUP—either can be any of the protocols supported by the Cisco BTS 10200.

SIP-T in Release 4.2 complies with the following specifications:

HKTA 2202 Issue 3, Aug 2001 (for ISUP compliance)

RFC 3372 (the SIP-T specification)

RFC 3398 (SIP to ISUP mapping)

RFC 3204 (MIME media types for ISUP encapsulation)

RFC 3261 (core SIP functionality)

RFC 2976 (SIP INFO method - for suspend and resume functionality)

The following is a list of SIP message types and the corresponding ISUP message that is encapsulated within the associated SIP message type.

SIP INVITE - ISUP IAM

SIP 180 response - ISUP ACM

SIP (other 18X responses) - ISUP CPG

SIP 200 response - ISUP ANM or CON

SIP BYE - ISUP REL

SIP CANCEL - ISUP REL

SIP Error response (400 or above) - ISUP REL

SIP INFO - ISUP SUS or RES

Release 4.2 SIP-T Requirement

When provisioning a SIP-T trunk-group, a specified ISUP variant must be associated with the trunk group. The association, in accordance with RFC 3204 (MIME media types for ISUP), is accomplished by specifying an ISUP Version (such as HONGKONG_ISUP) with an associated ISUP Base (such as itu-t92+). A fully compliant version of SIP-T that provides encode and decode capabilities for ISUP is also required.

The SIP-T Protocol

SIP-T is a protocol that utilizes SIP as a mechanism to transport ISUP messages between two IP enabled switches so that PSTN specific information are preserved when a call originates and terminates in the PSTN.

RFC 3204 defines the method by which ISUP information is carried within SIP messages for implementing SIP-T. The RFC defines a MIME media type to do this. A MIME header defines the version and base of the ISUP messages being carried within SIP. The version is analogous to an ISUP variant, while the base is similar to an ISUP protocol family.

New and Modified Tables

There are new and modified tables in the Release 4.2 SIP-T release.

New Tables

The SIPT-ISUP-VER-BASE and SIPT-ISUP-VER-ALIAS tables are new to the Release 4.2 SIP-T Release.

SIPT-ISUP-VER-BASE Table

The SIPT-ISUP-VER-BASE table is new to Release 4.2. The table contains a list of all supported SIP-T ISUP versions and their base family names. The table is used to validate the ISUP version information stored in the Softswitch trunk group profile table.

Table 1

Table Name

SIPT-ISUP-VER-BASE

Table Containment Area

EMS

Command Line Actions

show

show sipt-isup-ver-base id=Q761_HONGKONG;
show sipt-isup-ver-base

Primary Key Token(s)

id

Add Rules

None

Change Rules

None

Delete Rules

None


SIPT-ISUP-VER-BASE Table Requirements

Table 2 SIPT-ISUP-VER-BASE Tokens

Token
PK/FK
Type
Values
Mandatory/ Optional

ID

SIP-T ISUP version name.

PK

VARCHAR(32)

1-32 ASCII characters

Mandatory

BASE

SIP-T ISUP base name.

 

VARCHAR(32)

1-32 ASCII characters

Mandatory


SIPT-ISUP-VER-ALIAS Table

This is a new table in 4.2. This table contains aliases to the SIP-T ISUP version names defined in the SIP-T ISUP version base table.

RFC-3204 does not specify the string values to use for the version. Instead, the RFC leaves it up to the two communicating Softswitches to agree on a common value for the version string. If two Cisco BTS 10200 softswitches are communicating, then using this table is not necessary, because a pre-defined version (ID) value in the SIPT-ISUP-VERSION-BASE table can be used.

The SIPT-ISUP-VER-ALIAS table was implemented to allow Cisco BTS 10200 users to easily communicate with other Softswitches. In case the Cisco BTS 10200 is communicating with another softswitch, the table can be used to set the MIME Version string to the same value the far end softswitch is using.

Table 3

Table Name

SIPT-ISUP-VER-ALIAS

Table Containment Area

EMS, Call Agent

Command Line Actions

show, add, change, delete

add sipt-isup-ver-alias id=Q761_HONGKONG; 
alias=hong-kong;
show sipt-isup-vers-alias id=Q761_HONGKONG;
change sipt-isup-ver-alias id=Q761_HONGKONG; 
alias=HONGKONG;
delete sipt-isup-ver-alias id=Q761_HONGKONG;

Primary Key Token(s)

id

Add Rules

None

Change Rules

None

Delete Rules

id must not exist in any dependency table.


SIPT-ISUP-VER-ALIAS Table Requirements

Table 4 SIPT-ISUP-VER-ALIAS Syntax Description

Token
PK/FK
Type
Values
Mandatory/ Optional

ID SIP-T ISUP version name.

This version must exist in the SIPT-ISUP-VER-BASE table

PK

VARCHAR(32)

1-32 ASCII characters

Mandatory

ALIAS

Alias for SIP-T ISUP version name

UK

VARCHAR(32)

1-32 ASCII characters

Mandatory


Modified Tables

The SOFTSW-TG-PROFILE table was modified for the Release 4.2 SIP-T Release.

SOFTSW-TG-PROFILE Table

The Softswitch Trunk Group Profile (softsw-tg-profile) table holds all the information specific to a Softswitch trunk-group, such as id, protocol, indicators and echo suppression. The softsw-tg-profile record can be shared by multiple softswitch trunk groups. An ID must be created in this table before entries can be added to the Softswitch Trunk Group table.

The following modifications were made to the SOFTSW-TG-PROFILE table:

The values of SIPT-ISUP-VER must be one of the values defined in SIPT-ISUP-VER-BASE table.

New column, USE-SIPT-ISUP-BASE is added.

New column, SIPT-ISUP-BASE is added. This field is populated from the SIPT-ISUP-VER-BASE table if USE-SIPT-ISUP-BASE=Y.

Rules

CC-DIVERSION-SUPP AND DIVERSION-HEADER-SUPP Should be mutually exclusive.

IF CC-DIVERSION-SUPP=Y; THEN DIVERSION-HEADER-SUPP=N;

IF DIVERSION-HEADER-SUPP=Y; THEN CC-DIVERSION-SUPP=N;

BOTH FLAGS CAN BE SET TO "N".

IF PROTOCOL-TYPE=CMSS; THEN PRACK-FLAG MUST BE "Y";

IF PROTOCOL-TYPE=SIP-T; THEN PRACK-FLAG MUST BE "Y";

IF PROTOCOL-TYPE=SIP-T; then SIPT-ISUP-VER should be specified.

SIPT-ISUP-VER must be defined in the SIPT-ISUP-VER-BASE table.

Upgrade Rules

Prior to Release 4.2, ANSI was the only supported SIP-T variant. Because of this, during upgrade for all the defined SIP-T profiles, SIPT-ISUP-VER is set to ANSI_GR317, USE_SIPT_BASE to Y, and SIPT_ISUP_BASE to gr317.

Table 5

Table Name

SOFTSW-TG-PROFILE

Table Containment Area

Call Agent

Command Line Actions

show, add, change, and delete

show softsw-tg-profile id=softprf1;
add softsw-tg-profile id=softprf1; protocol-type=sip-t; 
sipt-isup-ver=Q761_HONGKONG;
change softsw-tg-profile id=softprf1; send-cpn=n;
delete softsw-tg-profile id=softprf1;

Primary Key Token(s)

id

Add Rules

None

Change Rules

None

Delete Rules

ID must exist.

ID cannot exist in any trunk-grp::tg-profile-id where tg-type=softsw


SOFTSW-TG-PROFILE Table Requirements


Note Table 6 contains only the three modified SOFTSW-TG-PROFILE fields; for the complete SOFTSW-TG-PROFILE table information, refer to the Command Line Interface Reference Guide (Release 4.1).


Table 6 SOFTSW-TG-PROFILE Syntax Description

Token
PK/FK
Type
Values
Mandatory/Optional

SIPT-ISUP-VER

This field defines the SIP-T ISUP version. This field is used only when the PROTOCOL-TYPE is SIP_T. This value must be defined in the SIPT-ISUP-VER-BASE table.

PK

VARCHAR(32)

1-32 ASCII characters

Mandatory

USE-SIPT-ISUP-BASE

If Y, SIP-T ISUP base version is included in the MIME header of the SIP-T message. This field is used only when the PROTOCOL-TYPE is SIP_T.

UK

CHAR(1)

Y/N (Default = N)

Mandatory

SIPT-ISUP-BASE

SIP-T ISUP base type. This field is populated from the SIPT-ISUP-VER-BASE table. It cannot be configured by the user.

 

VARCHAR(32)

1-32 ASCII characters

 

CPM

The CPM subsystem supports the new SIPT-ISUP-VER-BASE and SIPT-ISUP-VER-ALIAS tables, and the modified SOFTSW-TG-PROFILE table.

What to Provision

SIP-T softswitch trunk group profile. SIP-T ISUP version must be defined in the SIPT-ISUP-VER-BASE table.

Alias to predefined SIP-T ISUP versions (if needed).

When to Provision

Provision the following components before provisioning the SIP-T softswitch trunk group.

Example 1 Provisioning Example

add softsw-tg-profile id=ss-tg-prof; protocol-type=SIP-T; sipt-isup-ver=Q761_HONGKONG; 
use-sipt-ver-base=Y;
add sipt-isup-ver-alias id=Q761_HONGKONG; alias=hongkong;

DBM

The DBM subsystem supports the new SIPT-ISUP-VER-ALIAS tables, and the modified SOFTSW-TG-PROFILE table.