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,
page 1
•
Properties, page 7
•
Provisioning Examples, page 9
•
Obtaining Documentation, Obtaining Support, and Security Guidelines, page 10
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.
Cisco MGC Software Release 9.7(3)
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Understanding the SIP and ISUP Interworking for Call Hold and Terminal Portability Feature
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
SS7
GW
PGW
CPG
hold
SIP
INVITE
sendonly
MDCX
sendonly
200 OK
recvonly
ACK
200 OK
CPG
retrieve
INVITE
sendrecv
200 OK
Cisco MGC Software Release 9.7(3)
2
200 OK
sendrecv
ACK
250100
MDCX
sendrecv
Understanding the SIP and ISUP Interworking for Call Hold and Terminal Portability Feature
ISUP to SIP TP Success
SS7
ISUP to SIP TP Success
GW
SIP
PGW
SUSPEND
INVITE
sendonly
MDCX
sendonly
200 OK
recvonly
ACK
200 OK
RESUME
INVITE
sendrecv
MDCX
sendrecv
200 OK
200 OK
sendrecv
ACK
250101
Figure 2
Cisco MGC Software Release 9.7(3)
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Understanding the SIP and ISUP Interworking for Call Hold and Terminal Portability Feature
ISUP to EISUP to SIP Call Hold Success Flow
Figure 3
ISUP to EISUP to SIP Call Hold Success Flow
SS7
GW
PGW2
PGW1
CPG
hold
CPG
hold
MDCX
sendonly
200 OK
CPG
retrieve
Notification [Request]
Unjoin_Rx
INVITE
sendonly
200 OK
recvonly
ACK
Notification [Ack]
Unjoin_Rx
CPG
retrieve
MDCX
sendrecv
SIP
Notification [Request]
Join_both
INVITE
sendrecv
200 OK
sendrecv
ACK
Notification [Ack]
Join_Both
250102
200 OK
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.
Cisco MGC Software Release 9.7(3)
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Understanding the SIP and ISUP Interworking for Call Hold and Terminal Portability Feature
Figure 4
SS7
ISUP to SIP Hold Reject by SIP Side 5XX
GW
PGW
CPG
hold
SIP
INVITE
sendonly
5xx
ACK
250103
CPG
retrieve
SIP to SS7 Hold Rejected by SS7 Side (MGCP) 4XX
Figure 5
SS7
SIP to SS7 Hold Rejected by SS7 Side (MGCP) 4XX
GW
PGW
MDCX
recvonly
SIP
INVITE
sendonly
4xx
ACK
250104
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.
Cisco MGC Software Release 9.7(3)
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Understanding the SIP and ISUP Interworking for Call Hold and Terminal Portability Feature
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_book0
9186a00807de145.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_note09186a00807ffa
15.html
Cisco MGC Software Release 9.7(3)
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Properties
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
Cisco MGC Software Release 9.7(3)
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Properties
Table 1
New SIP Properties for SIP and ISUP Interworking for Call and TP (continued)
Property
Definition
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"
Cisco MGC Software Release 9.7(3)
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Provisioning Examples
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
Cisco MGC Software Release 9.7(3)
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Obtaining Documentation, Obtaining Support, and Security Guidelines
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
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Cisco MGC Software Release 9.7(3)
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