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Cisco PGW 2200 Softswitch

SIP and ISUP Interworking for Call Hold and Terminal Portability

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SIP and ISUP Interworking for Call Hold and Terminal Portability

Table Of Contents

SIP and ISUP Interworking for Call Hold and Terminal Portability

Understanding the SIP and ISUP Interworking for Call Hold and Terminal Portability Feature

Call Flows

ISUP to SIP Hold Success

ISUP to SIP TP Success

ISUP to EISUP to SIP Call Hold Success Flow

ISUP to SIP Hold Reject by SIP Side 5XX

SIP to SS7 Hold Rejected by SS7 Side (MGCP) 4XX

Limitations

Related Documents

Supported Standards, MIBs, and RFCs

Supported Platforms

Prerequisites for Using this Feature

Properties

Provisioning Examples

Obtaining Documentation, Obtaining Support, and Security Guidelines

Glossary


SIP and ISUP Interworking for Call Hold and Terminal Portability


Document Release History

Publication Date
Comments

December 3, 2009

Updated the values for CallHoldInterworkingEnabled.

July 10, 2007

Initial version of the document.


Feature History

Release
Modification

9.7(3)

The SIP and ISUP Interworking for Call Hold and Terminal Portability feature was introduced on the Cisco MGC software.


This document describes the SIP and ISUP Interworking for Call Hold and Terminal Portability feature.

This feature is described in the following sections:

Understanding the SIP and ISUP Interworking for Call Hold and Terminal Portability Feature

Properties

Provisioning Examples

Obtaining Documentation, Obtaining Support, and Security Guidelines

Understanding the SIP and ISUP Interworking for Call Hold and Terminal Portability Feature

This feature supports the message mapping between SIP and ISUP for call hold and terminal portability (TP) supplementary services on the PGW 2200. The implementation is based on Q.1912.5 Annex B.10 for Call Hold and Annex B.13 for Terminal Portability (TP). Q.1912.5 defines signaling interworking between SIP and ISUP. ISUP and HSI interworking for Call hold and TP is also supported. The ISUP call hold and TP messages are mapped to EISUP notification message .

The TP supplementary service allows you to move a terminal from one socket to another within one given basic access during the active state of the call. It also allows you to move a call from one terminal to another terminal within one given basic access during the active phase of the call.

PGW also supports ISUP and SIP/HSI interworking for Call hold and TP across EISUP (inter PGW). The following scenario is supported : ISUP->PGW1->PGW2->SIP/HSI. Either ISUP invokes call hold or SIP/HSI invokes call hold is supported.

PGW does not invoke the call hold. The call hold is invoked by an SS7 switch or a SIP/H323 endpoint. PGW does the signaling conversion . For example, PGW converts an SS7 hold signal to a SIP or an H.323 hold signal.

Call Flows

In Figure 1 through Figure 5, each shows a different call flow.

ISUP to SIP Hold Success

Figure 1 ISUP to SIP Hold Success

ISUP to SIP TP Success

Figure 2 ISUP to SIP TP Success

ISUP to EISUP to SIP Call Hold Success Flow

Figure 3 ISUP to EISUP to SIP Call Hold Success Flow

ISUP to SIP Hold Reject by SIP Side 5XX

If an ISUP hold is rejected by the SIP side but there is no ISUP message that the ISUP side hold was rejected, LCM holds the reject information. Later, if an ISUP retrieve message is received, LCM drops it. If the ISUP side has not invoked hold but it receives a retrieve message, the retrieve message is dropped by the ISUP module because it is not in a hold state.

Figure 4 ISUP to SIP Hold Reject by SIP Side 5XX

SIP to SS7 Hold Rejected by SS7 Side (MGCP) 4XX

Figure 5 SIP to SS7 Hold Rejected by SS7 Side (MGCP) 4XX

Limitations

The following are limitations for this feature:

ISUP TP after Call hold is ignored

Because ISUP Call Hold and TP are mapped into the same message INVITE at the SIP side, they cannot work together. In fact, you cannot invoke call hold and TP together.

This feature supports call hold only after a call is answered.

ISUP and SIP call hold interworking are supported only after the call is answered.

Checkpoint and failover

The PGW 2200 cannot support a sip invoke hold/resume to tdm after a switch over or resume the hold call after a switch over. Also, the PGW 2200 cannot support an ss7 invoke hold/resume to sip after a switch over or resume the hold sip call after a switch over.

Call hold from both sides at the same time is not supported.

If the SS7 side initiates a hold and the hold does not complete, the other side (the SIP side) initiates another direction hold.

Embedded call hold in SIP

Embedded ISUP in SIP is not investigated. No GW hold action happens if the received embedded ISUP message (such as SIP-T, SIP-I, SIP-GTD) in SIP is requesting call hold and TP.

For call hold interworking between ISUP and HSI, HSI needs an H.245 procedure for codec negotiation when retrieving a call. Provision HSI as follows:

prov-add:name=sys_config_dynamic, InitiateTCSAfterFSCall=true 
prov-add:name=sys_config_dynamic, TransmitTCSAfterFSCall=true

Related Documents

This document contains information that is related to this feature. The documents that contain additional information related to the Cisco Media Gateway Controller (MGC) are at the following url:

http://www.cisco.com/en/US/products/hw/vcallcon/ps2027/tsd_products_support_series_home.html

Supported Standards, MIBs, and RFCs

RFCs

This feature supports the following RFCs:

RFC 2543, SIP: Session Initiation Protocol

RFC 3264, An Offer/Answer Model with Session Description Protocol (SDP) (partially compliant)

Supported Platforms

The hardware platforms supported for the Cisco MGC software are described in the Cisco Media Gateway Controller Hardware Installation Guide at

http://www.cisco.com/en/US/partner/products/hw/vcallcon/ps2027/products_installation_guide_book09186a00807de145.html

Prerequisites for Using this Feature

The Cisco PGW 2200 must be running Cisco MGC software Release 9.7(3). Prerequisites for this release can be found in the Release Notes for the Cisco Media Gateway Controller Software Release 9.7(3) at

http://www.cisco.com/en/US/partner/products/hw/vcallcon/ps2027/prod_release_note09186a00807ffa15.html

Properties

The properties in this section are used for this feature. For information on other properties for the Cisco MGC software, see Cisco PGW 2200 Softswitch Release 9 Provisioning Guide (through Release 9.7) at

http://www.cisco.com/en/US/docs/voice_ip_comm/pgw/9/provisioning/guide/prvgde.html

The properties used for this feature are described in Table 1.

Table 1 New SIP Properties for SIP and ISUP Interworking for Call and TP 

Property
Definition

CallHoldInterworkingEnabled

Indicates whether Cisco PGW 2200 Softswitch interworks call hold and TP between SIP/H.323, EISUP, and ISUP. When this property is configured as disabled, Cisco PGW 2200 Softswitch drops HOLD and TP indications coming from the ISUP side. If the property is configured enabled, Cisco PGW 2200 Softswitch maps the ISUP side HOLD and TP to SIP Re-Invite.

Valid values:

0—TDM to IP hold interworking disabled (but IP to TDM hold interworking enabled)

1—Bidirection hold interworking enabled

2—IP to TDM hold interworking disabled (but TDM to IP hold interworking enabled)

3—Bidirection hold interworking disabled

Default Value: 1

Dynamically Reconfigurable: yes

SipCallHoldMethod

Indicates which call hold method the PGW 2200 uses. PGW has two SIP call hold methods. One is according to RFC2543, setting c=0.0.0.0, the other is according to RFC3264, setting a=sendonly or a=inactive. Both are supported, but when PGW initiates call hold, there must be a rule to follow. This provision determines how PGW handles a received call hold request from the ISUP/HSI side, but if an RFC2543 call hold request is received before PGW sends a call hold request, PGW sets itself in RFC2543 call hold method even if it is configured to RFC3264. If an RFC3264 call hold request is received before PGW sends a call hold request, PGW sets itself in RFC3264 call hold method even if it is configured to RFC2543.

Valid Values:

0 (RFC3264 method : "a=sendonly")

1 (RFC2543 method "c=0.0.0.0")

Default Value: 0

Property Domain: _X_SigPath

Protocol Family: SIP

Dynamically Reconfigurable: yes

NetSuspendResumeMap2Invite

Indicates whether or not the Cisco PGW 2200 Softswitch maps a mid-call ISUP SUSPEND/RESUME, with a network-initiated value, to a SIP Re-Invite.

Valid Values:

0—Do not map ISUP SUSPEND/RESUME to SIP Re-Invite

1—Map ISUP SUSPEND/RESUME (network initiate) to SIP Re-Invite (similar to Hold/TP service).


To provision the RFC3264 call hold method:

prov-ed:sigsvcprop:name="sip-path",sipcallholdmethod="0" 

To provision SIP using the RFC2543 call hold method:

prov-ed:sigsvcprop:name="sip-path",sipcallholdmethod="1"

Provisioning Examples

SS7 Configuration on the PGW 2200

numan-add:dialplan:custgrpid="4444"
prov-add:OPC:NAME="opc",DESC="Our own point code",NETADDR="1.24.1",NETIND=2,TYPE="TRUEOPC"
prov-add:DPC:NAME="dpc1",DESC="SS7 dpc1",NETADDR="1.24.3",NETIND=2
prov-add:EXTNODE:NAME="slt-1",DESC="SLT 2600",TYPE="SLT",ISDNSIGTYPE="N/A",GROUP=0
prov-add:SS7PATH:NAME="ss7svc-1",DESC="SS7 service to 
DPC-1.24.3",MDO="Q761_GERMAN",CUSTGRPID="4444",SIDE="network",DPC="dpc1",OPC="opc"
prov-add:SESSIONSET:NAME="ss7session-1",EXTNODE="slt-1",IPADDR1="IP_Addr1",PEERADDR1="10.0
.4.41",PORT=7000,PEERPORT=7000,TYPE="BSMV0"
prov-add:LNKSET:NAME="linkset-1",DESC="Linkset 1 to 
SS7",APC="dpc1",PROTO="SS7-ITU",TYPE="IP"
prov-add:SS7ROUTE:NAME="ss7route-1",DESC="Route to 
DPC-1.24.3",OPC="opc",DPC="dpc1",LNKSET="linkset-1",PRI=1
prov-add:C7IPLNK:NAME="ss7link-1",DESC="Signal link 
1-1",LNKSET="linkset-1",SLC=0,PRI=1,TIMESLOT=0,SESSIONSET="ss7session-1"
 
prov-add:EXTNODE:NAME="gw-1",DESC="gw-1",TYPE="AS5400",ISDNSIGTYPE="IUA",GROUP=0
prov-add:MGCPPATH:NAME="mgcp-path-1",DESC="MGCP",EXTNODE="gw-1"
prov-add:IPLNK:NAME="mgcplnk-1",DESC="iplink to 
gw-1",SVC="mgcp-path-1",IPADDR="IP_Addr1",PORT=2427,PEERADDR="10.0.4.43",PEERPORT=2427,PRI
=1

SIP Configuration on the PGW 2200

prov-add:SIPPATH:NAME="sip-path",DESC="Nothing defined",MDO="IETF_SIP"
prov-add:SIPLNK:NAME="sip-lnk",DESC="notSet",SVC="sip-path",IPADDR="Virtual_IP_Addr1",PORT
=5060,PRI=1
prov-ed:sigsvcprop:name="sip-path",callholdinterworkingenabled="1"
prov-ed:sigsvcprop:name="sip-path",sipcallholdmethod="0"

H.323 Configuration on the PGW 2200

prov-add:EXTNODE:NAME="HSI-1",DESC="EISUP to HSI",TYPE="H323",ISDNSIGTYPE="N/A",GROUP=0
prov-add:EISUPPATH:NAME="eisup-hsi-1",DESC="Path to 
HSI-1",EXTNODE="HSI-1",CUSTGRPID="4444"
prov-add:IPLNK:NAME="eisuplnk-hsi-1",DESC="IP link to 
HSI-1",SVC="eisup-hsi-1",IPADDR="IP_Addr1",PORT=8003,PEERADDR="10.0.7.231",PEERPORT=8003,P
RI=1,IPROUTE=""
prov-add:trnkgrp:name="7000",type="IP",svc="eisup-hsi-1"
prov-add:trnkgrpprop:name="7000",CustGrpId="4444",btechprefix="null"

H.323 Related Configuration on HSI

SYS_CONFIG_STATIC.VSCA_IPADDR1 = 10.0.33.20
SYS_CONFIG_STATIC.VSCA_PORT_NUMBER1 = 8003
SYS_CONFIG_DYNAMIC.InitiateTCSAfterFSCall = 1
SYS_CONFIG_DYNAMIC.TransmitTCSAfterFSCall = 1

Obtaining Documentation, Obtaining Support, and Security Guidelines

For information on obtaining documentation, obtaining support, providing documentation feedback, security guidelines, and also recommended aliases and general Cisco documents, see the monthly What's New in Cisco Product Documentation, which also lists all new and revised Cisco technical documentation at:

http://www.cisco.com/en/US/docs/general/whatsnew/whatsnew.html

Glossary

Table 2 contains expansions of acronyms and technical terms used in this feature module.

Table 2 Acronyms and Expansions

Acronym
Expansion

EISUP

Enhanced ISUP

GTD

Generic Transparency Descriptor

HSI

H.323 Signalling Interface

ISUP

ISDN User Part

MGC

Media Gateway Controller

MML

Man-Machine Language

PGW

PSTN gateway

PSTN

Public Switched Telephony Network

SDP

Session Description Protocol

SIP

Session Initiation Protocol

TP

Terminal Portability