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TCP Transport for SIP, Phase II

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TCP Transport for SIP Phase II Feature Module

Feature Description

Benefits

Prerequisites

Restrictions or Limitations

Related Features and Technology

Related Documents

Supported Standards, MIBs, and RFCs

Upgrading to Support This Feature

XECfgParm.dat Configuration Tasks

New XECfgParm.dat Parameters

Modified XECfgParm.dat Parameters

Configuring the XECfgParm.dat File

Verifying the XECfgParm.dat Changes

Troubleshooting the XECfgParm.dat Configuration

Provisioning Tasks

Setting the Transport Protocol for a Trunk Group

Troubleshooting Provisioning Data

Configuration Examples

Provisioning Examples

Software Changes for This Feature

XECfgParm.dat Parameters

Feature Measurements

Billing Interface

Provisioning Properties

Provisioning Worksheets

Obtaining Documentation and Submitting a Service Request

Glossary


TCP Transport for SIP Phase II Feature Module

Feature History

Release
Modification

9.7(3)

The TCP Transport for SIP Phase I feature was introduced on the Cisco PGW 2200 Softswitch software.

9.8(1)

The TCP Transport for SIP Phase II feature was introduced on the Cisco PGW 2200 Softswitch software.


This document describes the TCP Transport for SIP Phase II feature for the Cisco PGW 2200 Softswitch. The feature is described in the following sections:

•Feature Description

•XECfgParm.dat Configuration Tasks

•Provisioning Tasks

•Configuration Examples

•Provisioning Examples

•Software Changes for This Feature

•Obtaining Documentation and Submitting a Service Request

•Glossary

Feature Description

The TCP Transport for SIP Phase I feature introduced support for multiple transport protocols on the Cisco PGW 2200 Softswitch in Release 9.7(3). This feature extends the benefits of TCP Transport for SIP Phase I by adding more flexible configuration options for the UDP and TCP transport protocols.

Benefits

This feature provides the following benefits:

•A dynamic mode that provides simultaneous support for TCP and UDP

•Improved compatibility with RFC 3263, 3261, 2915, and 2782

•Support for switching between TCP and UDP during a session

•Support for calls that utilize a different transport protocol in each call leg

•Support for DNS-based selection of a call's transport protocol and destination address

Prerequisites

The Cisco PGW 2200 Softswitch must be running Cisco PGW 2200 Softswitch Software Release 9.8(1). Prerequisites for this release can be found in the Release Notes for the Cisco PGW 2200 Softswitch Software Release 9.8(1) at

http://www.cisco.com/en/US/partner/docs/voice_ip_comm/pgw/9/release/note/rn981.html

Restrictions or Limitations

This feature has the following limitations:

•Disabling TCP or UDP traffic—By default, the Cisco PGW 2200 Softswitch accepts and processes SIP messages using TCP and UDP. If you wish to completely disable a transport protocol on your network, we recommend that you use a firewall to block the undesired traffic.

•Siptransportmode property does not affect SIP responses or incoming SIP messages—The siptransportmode property affects the transport protocol of SIP requests only. It does not affect the transport protocol that the Cisco PGW 2200 Softswitch uses to send SIP responses or incoming SIP requests or responses.

Related Features and Technology

The following features are related to TCP Transport for SIP Phase II:

•SIP Profiles

•Incoming IP Trunks

•TCP Transport for SIP Phase I

Related Documents

This document contains information that is strictly related to this feature. Additional information about the Cisco PGW 2200 Softswitch is available at

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

Supported Standards, MIBs, and RFCs

This section identifies the new or modified standards, MIBs, and RFCs that are supported by this feature.

RFCs

Table 1 summarizes the RFC compliance provided by this feature.

Table 1 RFC Compliance

RFC
Capability
Compliance

2872

The DNS resource record (SRV) used to specify the location of services

Full

2915

The DNS resource record (NAPTR) used to specify the Naming Authority Pointer

Partial

3261

SIP: Session Initiation Protocol

Partial

3263

Session Initiation Protocol (SIP): Locating SIP Servers

Partial


Upgrading to Support This Feature

For instructions on how to migrate to Cisco PGW 2200 Softswitch Release 9.8(1), refer to the Release Notes for the Cisco PGW 2200 Softswitch Software Release 9.8(1) at

http://www.cisco.com/en/US/partner/docs/voice_ip_comm/pgw/9/release/note/rn981.html

The Release 9.8 migration process installs the TCP Transport for SIP Phase II feature. The migration script completes the following tasks:

•Adds the siptransportmode property to all existing SIP trunk groups

•Sets siptransportmode equal to the value of the SIP.transportprotocol parameter for all existing trunk groups

•Removes the SIP.transportProtocol parameter from the XECfgParm.dat file

•Sets the SIP.udp2tcp_byte_xover and SIP.naptr_record_locate parameters to default values.

XECfgParm.dat Configuration Tasks

The following sections describe the XECfgParm.dat configuration tasks for this feature.

New XECfgParm.dat Parameters

This section contains the steps necessary for configuration of the Cisco PGW 2200 Softswitch software to support this feature. This feature introduces the following XECfgParm.dat parameters:

•SIP.dns_query_timer—The amount of time in seconds before a Cisco PGW 2200 Softswitch DNS NAPTR query times out

•SIP.naptr_record_locate—Specifies the type of query the Cisco PGW 2200 Softswitch uses to determine the preferred transport protocol of a remote proxy

•SIP.transaction_based_dns_query—Specifies when the Cisco PGW 2200 Softswitch sends DNS requests for transport protocol information

•SIP.udp2tcp_byte_xover—Determines the SIP message size (in bytes) above which the Cisco PGW 2200 Softswitch switches to TCP transport

For more information about the new XECfgParm.dat parameters, see XECfgParm.dat Parameters.

Note Do not include the SIP.transaction_based_dns_query and SIP.dns_query_timer values in the xecfgparm.dat file unless you need to change the default values.

Modified XECfgParm.dat Parameters

The Cisco PGW 2200 Softswitch Release 9.8(1) migration procedure removes the SIP.transportProtocol XECfgParm.dat parameter. For more information, see XECfgParm.dat Parameters.

Configuring the XECfgParm.dat File

If you are installing and configuring the Cisco PGW 2200 Softswitch software on your system for the first time, use the procedures in the Cisco PGW 2200 Softswitch Release 9.8 Installation and Configuration Guide, coming back to this section once you encounter the new XECfgParm.dat file parameters.

Caution Configuration of the Cisco PGW 2200 Softswitch software requires that you shut down the Cisco PGW 2200 Softswitch. In a simplex system, the Cisco PGW 2200 Softswitch does not process calls during system shutdown. In a continuous service system, your system loses the ability to maintain calls during a critical event if the system software on one of the Cisco PGW 2200 Softswitch hosts is shut down.

To configure the new XECfgParm.dat file parameters, perform the following steps:

Step 1 Open the /opt/CiscoMGC/etc/XECfgParm.dat file on the active and standby Cisco PGW 2200 Softswitch hosts using a text editor, such as vi.

Step 2 Ensure that the pom.dataSync parameter is set to false on the active and standby Cisco PGW 2200 Softswitch hosts.

Step 3 Search for the new parameters and enter the desired value for each on the active and standby Cisco PGW 2200 Softswitch hosts.

Step 4 Save your changes and close the text editor.

Verifying the XECfgParm.dat Changes

To verify the XECfgParm.dat changes for this feature, perform the following steps:

Step 1 Log in to the standby Cisco PGW 2200 Softswitch as root and move to the etc subdirectory: 

cd /opt/CiscoMGC/etc

Step 2 Open the XECfgParm.dat using a text editor, such as vi.

Step 3 Search for the new parameters and verify that the displayed values are correct.

Note If the value is incorrect, correct the value and proceed to the next step.

Step 4 Save your changes and close the text editor.

Step 5 Manually stop the Cisco PGW 2200 Softswitch software on the standby Cisco PGW 2200 Softswitch host: 

/etc/init.d/CiscoMGC stop

Step 6 Once the software shutdown is complete, manually start the Cisco PGW 2200 Softswitch by entering the following command: 

/etc/init.d/CiscoMGC start

Step 7 Log in to the active Cisco PGW 2200 Softswitch host, start an MML session, and enter the following command to perform a manual switchover. 

mml> sw-over::confirm

Note The Cisco PGW 2200 Softswitch automatically generates site alarms until the out-of-service (OOS) host returns to an in-service (IS) state.

Step 8 Repeat step Step 2 through Step 7 on the newly standby Cisco PGW 2200 Softswitch host. Once you have verified the settings on both hosts, the procedure is complete.

Troubleshooting the XECfgParm.dat Configuration

Use the following troubleshooting steps for the XECfgParm.dat parameters introduced for this feature:

•After it switches from UDP to TCP, if the Cisco PGW 2200 Softswitch encounters a TCP transport layer error caused by a message size above the SIP.udp2tcp_byte_xover value, it reverts to UDP for all traffic sent to the domain in which the error occurred.

•When the Cisco PGW 2200 Softswitch reboots during the upgrade procedure, it automatically generates site alarms until the out-of-service (OOS) host returns to an in-service (IS) state.

Provisioning Tasks

Information about provisioning is available in the Cisco PGW 2200 Softswitch Release 9.8 Provisioning Guide in the following sections:

•Planning for Provisioning

http://www.cisco.com/en/US/docs/voice_ip_comm/pgw/9/provisioning/guide/R9PlnPrv.html

•MML Basics

http://www.cisco.com/en/US/docs/voice_ip_comm/pgw/9/provisioning/guide/R9MMLCfg.html

Setting the Transport Protocol for a Trunk Group

The siptransportmode parameter specifies the transport protocol permitted on a trunk group. To set the set the transport protocol for an existing trunk group, use the prov-ed:profile command. 

prov-ed:profile:name="p9000",siptransportmode="0"

For more information about the siptransportmode parameter, see Provisioning Properties.

Troubleshooting Provisioning Data

Use the following troubleshooting steps for the provisioning data introduced for this feature:

•If the Cisco PGW 2200 Softswitch encounters a TCP transport layer error after switching from UDP to TCP, it reverts to UDP for all traffic sent to the domain in which the error occurred.

Configuration Examples

This section provides a configuration example for the XECfgParm.dat parameters associated with this feature. 

SIP.udp2tcp_byte_xover = 1300

SIP.naptr_record_locate = 1

SIP.transaction_based_dns_query = 1

SIP.dns_query_timer = 5

This example sets the following options:

•The Cisco PGW 2200 Softswitch switches from UDP transport to TCP transport at 1300 bytes

•The Cisco PGW 2200 Softswitch uses a NAPTR query to determine the preferred transport protocol and remote IP address

•The Cisco PGW 2200 Softswitch uses DNS NAPTR and DNS SRV queries for all SIP messages

•DNS NAPTR queries time out after 5 seconds

Additional configuration examples for the Cisco PGW 2200 Softswitch software can be found in the Cisco PGW 2200 Softswitch Release 9.8 Installation and Configuration Guide.

Provisioning Examples

This section provides a provisioning example for this feature. Additional provisioning examples can be found in the Cisco PGW 2200 Softswitch Release 9.8 Provisioning Guide. 

________________________________________

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

; Trunk Group Properties

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

prov-add:trnkgrp:name="9000",type="SIP_IN",svc="sip-path",selseq="ASC" 

________________________________________

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

; Profile Properties

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

prov-add:profile:name="p9000",type="SIPPROFILE",trustlevel="0",custgrpid="1111",mgcdomain=
"sh-shuihu.cisco.com" 

________________________________________

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

; Adding a Trunk Group to a Profile

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

prov-add:trnkgrpprof:name="9000",profile="p9000" 

________________________________________

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

; Setting the transport protocol for a trunk group

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

prov-ed:profile:name="p9000",siptransportmode="0"

Software Changes for This Feature

The following sections describe software changes related to this feature:

•XECfgParm.dat Parameters

•Feature Measurements

•Billing Interface

•Provisioning Properties

•Provisioning Worksheets

XECfgParm.dat Parameters

The XECfgParm.dat file configuration parameters associated with this feature are defined in Table 2. For information on the other XECfgParm.dat parameters, see the Cisco PGW 2200 Softswitch Release 9.8 Installation and Configuration Guide.

Table 2 XeCfgParm.dat Parameter Definitions  

Configuration Parameter
Definition

SIP.dns_query_timer

The amount of time in seconds before a Cisco PGW 2200 Softswitch DNS NAPTR query times out.

Valid values: 1-30

Default: 5

Note Do not add this property to the Xecfgparm.dat file unless you need to modify the default value. If the parameter is not present in the Xecfgparm.dat file, the Cisco PGW 2200 Softswitch uses the default value. We recommend that you contact Cisco support before modifying this property.

Note If the DNS NAPTR query times out, the Cisco PGW 2200 Softswitch sends a UDP SRV query, TCP SRV query, and an A query simultaneously to determine the IP address and port number of the destination host. The Cisco PGW 2200 Softswitch processes the query results in the following order:

1. UDP SRV query

2. TCP SRV query

3. A query

SIP.naptr_record_locate

Specifies the type of query the Cisco PGW 2200 Softswitch uses to determine the preferred transport protocol of a remote proxy. The Cisco PGW 2200 Softswitch uses the query result for outgoing SIP trunk groups with the siptransportmode property set to Dynamic.

Valid values:

•0 = The Cisco PGW 2200 Softswitch uses UDP transport and a UDP SRV query to determine the remote IP address.

•1 = The Cisco PGW 2200 Softswitch uses a DNS NAPTR query to determine the preferred transport protocol and a DNS SRV query to determine the remote IP address.

Default: 1

SIP.transaction_based_dns_query

Specifies when the Cisco PGW 2200 Softswitch sends DNS requests for transport protocol information.

Note Do not add this property to the Xecfgparm.dat file unless you need to modify the default value. If the parameter is not present in the Xecfgparm.dat file, the Cisco PGW 2200 Softswitch uses the default value. We recommend that you contact Cisco support before modifying this property.

Valid values:

•0 = The Cisco PGW 2200 Softswitch uses DNS NAPTR and DNS SRV queries for the first SIP message in a call dialog only. The Cisco PGW 2200 Softswitch uses a DNS A query for mid-call SIP messages. This setting provides backwards compatibility for Release 9.7.

•1 = The Cisco PGW 2200 Softswitch uses DNS NAPTR and DNS SRV queries for all SIP messages. This setting provides RFC 3263 compatibility.

Default: 0

SIP.TransportProtocol

This feature eliminates the SIP.TransportProtocol parameter.

TCP transport for SIP Phase II eliminates the SIP.TransportProtocol that was introduced in TCP Transport for SIP Phase I and replaces it with the siptransportmode trunk group property. For more information about the siptransportmode property, see Provisioning Properties.

SIP.udp2tcp_byte_xover

Determines the SIP message size (in bytes) above which the Cisco PGW 2200 Softswitch switches to TCP transport. This property applies to outgoing SIP traffic only.

Valid values: Integer

•0 = The Cisco PGW 2200 Softswitch does not switch from UDP to TCP regardless of the SIP message size.

•1-10000 = The Cisco PGW 2200 Softswitch switches to TCP transport for messages above the specified size (in bytes).

Note This property overrides the siptransportmode parameter.

Default: 0


Feature Measurements

The TCP Transport for SIP Phase II feature allows the Cisco PGW 2200 Softswitch to transmit SIP traffic using the TCP and UDP transport protocols. Release 9.8(1) introduces four new measurements that show the usage of each transport protocol (see Table 3).

Table 3 Feature Measurements

Measurement
Definition
Logging Interval

SIPSP: XMIT UDP MSG TOT

The total number of messages sent using UDP

15

SIPSP: RCV UDP MSG TOT

The total number of messages received through UDP

15

SIPSP: XMIT TCP MSG TOT

The total number of messages sent through TCP

15

SIPSP: RCV TCP MSG TOT

The total number of messages received though TCP

15


For more information about measurements, see the Cisco PGW 2200 Softswitch Release 9 Operations, Maintenance, and Troubleshooting Guide.

Billing Interface

This section identifies the call detail record (CDR) data added for this feature. For billing interface information for the rest of the Cisco PGW 2200 Softswitch software, refer to the Cisco PGW 2200 Softswitch Release 9 Billing Interface Guide.

Table 4 SIP Ingress Transport CDR   

Name: SIP Ingress Transport

Tag: 4246

Source: MDL

Description/Purpose: Indicates the transport protocol used by the Cisco PGW 2200 Softswitch for incoming SIP messages. If the Cisco PGW 2200 Softswitch switches between UDP and TCP, this value is the name of the transport protocol used in the last message.

Format: Structured variable

Length in Octets: 1

Data Value:

Octet 1: Transport Protocol

Values:

•0 = UDP

•1 = TCP

Extended Data Value: No extended value.

General Information:

Release: Release 9.8 or later.

Answered (1010)

Deselected (1020)

Aborted (1030)

Release (1040)

Interrupted (1050)

Ongoing (1060)

Maintenance (1070)

External DB (1080)

End of Call (1110)

Y

N

Y

N

N

N

N

N

Y


Table 5 SIP Egress Transport CDR

Name: SIP Egress Transport

Tag: 4254

Source: MDL

Description/Purpose: Indicates the transport protocol used by the Cisco PGW 2200 Softswitch for outgoing SIP messages. If the Cisco PGW 2200 Softswitch switches between UDP and TCP, this value is the name of the transport protocol used in the last message.

Format: Structured variable

Length in Octets: 1

Data Value:

Octet 1: Transport Protocol

Values:

•0 = UDP

•1 = TCP

Extended Data Value: No extended value.

General Information:

Release: Release 9.8 or later.

Answered (1010)

Deselected (1020)

Aborted (1030)

Release (1040)

Interrupted (1050)

Ongoing (1060)

Maintenance (1070)

External DB (1080)

End of Call (1110)

Y

N

Y

N

N

N

N

N

Y


Provisioning Properties

Table 6 and Table 7 describe the provisioning properties used for this feature. For a full listing of all properties, refer to the Cisco PGW 2200 Softswitch Release 9.8 Provisioning Guide.

Table 6 Provisioning Property Parent Objects

Property Name
Parent Object
AVM
DPNSS
EISUP
IOCC
ISDNPRI
MGCP
QSIG
RLM
SESSION
SGCP
SIP
SS7-ANSI
SS7-China
SS7-ITU
SS7-Japan
SS7-UK
TALI-IOCC
TCAPOverIP
TrunkGroup
VSI
LI
CTI-QBE

siptransportmode

 

           

 

 

 

X

 

 

 

 

 

 

 

X

 

   

Table 7 Provisioning Properties

Property
Description

siptransportmode

Specifies the transport protocol permitted for a trunk group.

Valid values:

•0 = UDP

•1 = TCP

•2 = DYNAMIC

Default value: 0

Dynamically reconfigurable: Yes


Provisioning Worksheets

This section contains worksheets for the provisioning components required for this feature. For worksheets covering the rest of the provisioning components in the Cisco PGW 2200 Softswitch software, refer to the Cisco PGW 2200 Softswitch Release 9.8 Provisioning Guide.

Table 8 Provisioning Worksheets

Name
SIP Transport Mode
Description

9001

2 (Dynamic)

Dynamic mode

     
     
     
     
     
     
     
     
     

Obtaining Documentation and Submitting a Service Request

For information on obtaining documentation, submitting a service request, and gathering additional information, 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

Subscribe to the What's New in Cisco Product Documentation as a Really Simple Syndication (RSS) feed and set content to be delivered directly to your desktop using a reader application. The RSS feeds are a free service and Cisco currently supports RSS Version 2.0.

Glossary

Table 9 Acronym Expansions and Descriptions

Acronym
Expansion

CDR

Call detail record. A record containing call information for billing purposes.

Cisco MGC

The Cisco Media Gateway Controller. The software used on the Cisco PGW 2200 Softswitch.

DNS

Domain Name System. The system used on the Internet for translating names of network nodes into addresses.

MML

Man-Machine Language. Industry standard command line language used to manage telecommunications network elements, including the Cisco PGW 2200 Softswitch.

NAPTR

Naming Authority Pointer (NAPTR). A type of DNS resource record.

PGW

PSTN Gateway

SIP

Session Initiation Protocol. Protocol developed by the IETF MMUSIC Working Group as an alternative to H.323. SIP equips platforms to signal the setup of voice and multimedia calls over IP networks.

SRV

Service Record. A type of DNS resource record.

TCP

Transmission Control Protocol. Connection-oriented transport layer protocol that provides reliable full-duplex data transmission. TCP is part of the TCP/IP protocol stack.

UDP

User Datagram Protocol. A connectionless transport layer protocol used in the TCP/IP protocol stack. UDP is a simple protocol that exchanges datagrams without acknowledgments or guaranteed delivery, requiring that error processing and retransmission be handled by other protocols.


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