IP Multicast Homepage

This page is dedicated to information about Source Specific Multicast (SSM) and IGMPv3 related to these services in Cisco IOS. Please refer to the short Overview section below to understand the basics of SSM.

Index

• News / Change log
• Overview
• SSM Documentation
• CCO Documentation, Presentations, IETF drafts
• Cisco IOS SSM Software
• SSM enabled Applications
• SSM host middleware - IGMPv3 / IGMP v3lite / URD
• SSM enabled content on the Internet
• Other SSM Resources
• Contact Information

News / Change log

Source Specific Multicast (SSM) is an extension of IP Multicast in which datagram traffic is forwarded to receivers from only those multicast sources for which the receivers have explicitly expressed interest. SSM realizes a simple solution to addressing issues in IP Multicast, solves Denial of Service attack (DoS) related security concerns and provides for a simpler and easier scalable deployment of Multicast services in the Internet. SSM is primarily targeted for Internet Broadcast style applications where large receiver audiences require traffic from few well known sources. To co-exist with existing IP Multicast services, SSM is generally used within the defined range of addresses, 232.0.0.0/8, which is also called the SSM-Range.

SSM requires support in  receiver hosts and applications to signal source specific membership. The IETF designated standard protocol for this signaling is IGMPv3. IGMPv3 is the next generation of the IETF standards track protocol IGMP (Internet Group Membership Protocol). It adds support for source filtering, allowing receiver hosts and applications to specify an include or exclude list of sources sending to a multicast group from which traffic is to be received. With SSM, only include lists can be used, with standard Internet IP Multicast all membership modes of IGMPv3 are usable.

To enable timely deployment of SSM services in the face of non SSM enabled receiver applications or receiver host operating systems, Cisco IOS in addition to IGMPv3 also provides for two additional interim solutions to signal source specific membership:

• URD is the designated transition solution for content providers that want to use not (yet) SSM enabled receiver applications. URD allows to enable existing applications to be SSM capable without modifying any receiver host software (application nor operating system) - as long as the application is started via a web browser. URD stands for "URL Rendezvous Directory" and relies on the last-hop router towards a SSM receiver host to intercept URLs from a webserver to detect the source address of the SSM channel.

 
• IGMP v3lite is a solution for software developers to support SSM via the IGMPv3 API even on those operating systems, where IGMPv3 is not (yet) supported by the operating system itself. IGMP v3lite will also automatically rely on the operating system provided IGMPv3 stack if one is installed, so that upgrading of the host OS to IGMPv3 can be separated from upgrading the application. IGMP v3lite is based on host software (library and daemon, freely available), that send UDP encapsulated IGMPv3 messages to the last-hop router.

Both SSM and IGMPv3 are in the process of standardization in the IETF.
 

SSM Documentation

Documentation / Information on CCO

• SSM - Beyond Basic IP
  Overview on SSM solutions in IOS from technical product marketing.

 
• Cisco IOS 12.1(5)T feature documentation for SSM with IGMPv3, IGMP v3lite and URD on CCO.

This documentation describes the Cisco IOS SSM feature set for Cisco IOS 12.1(5)T.
 
• Cisco IOS 12.1(5)T feature documentation for IGMPv3 on CCO.

This documentation describes the IGMP v3 protocol implementation for Cisco IOS 12.1(5)T.

Presentations

• Source Specific Multicast (SSM) Solutions (8/2000, PDF, PPT)

This presentation is primarily targeted towards network operators. It revisits PIM-SM and MSDP operations, explains how SSM evolved out of it and describes it's advantages and characteristics as well as Cisco IOS solutions for SSM.
 
• Source Specific Multicast (SSM) for Application Developers (8/2000, PDF, PPT)

This presentation is targeted more towards potential SSM application developers. It focusses on the API and service differences and the walk through comparison of PIM-SM vs. SSM operations emphasizes on address reuse.
 
• Understanding URD and IGMP v3lite (9/2000, PDF, PPT)

Walk through of typical URD and IGMP v3lite operations, summary of URD and IGMPv3 characteristics.

IETF protocol/architecture drafts

draft-holbrook-ssm-arch-00.txt

This draft describes the SSM architecture and it's use of the 232/8 address range.
 

draft-holbrook-idmr-igmpv3-ssm-00.txt

This draft explains how IGMPv3 needs to be used in the SSM range (232/8).
 

draft-bhaskar-pim-ss-00.txt

This draft describes PIM SSM mode as used in Cisco IOS for SSM.
 

draft-ietf-idmr-igmp-v3-04.txt

This draft describes the IGMPv3 protocol.
 

draft-ietf-idmr-msf-api-01.txt

This draft describes the proposed API for IGMPv3 on hosts. A subset of this API is provided by the HSIL for implementation of IGMP v3lite.
 

draft-ietf-pim-sm-v2-new-00.txt

This is the new PIM-SM draft that logically incorporates PIM-SSM as a subset.
 

draft-shepherd-ssm232-00.txt

This draft describes the Best Current Practices (BCP) for using PIM -SSM within the SSM range.

• SSM with IGMPv3, IGMP v3lite and URD is supported in Cisco releases beginning with the following maintenance versions:
• Cisco IOS 12.1(5)T       -  available on CCO End of Nov. '00.
• Cisco IOS 12.1(5)E       -  available on CCO Dec. '00.
• Cisco IOS 12.0(15)S     - No finalized schedule yet.
• Cisco IOS 12.2                - Q1'2001
• Note: SSM with IGMP v3lite and URD but without IGMPv3 support was introduced with Cisco IOS 12.1(3)T. Please do not use that image for SSM related applications, because there were a couple of important issues that made SSM fail to work reliably in that release, and which have been corrected in the current images. Please use at least one of the above mentioned images to run SSM.

 
• Further Pre-builds of EFT and beta images for SSM are made available to Beta and EFT customers from this site. If you need SSM/IGMPv3 support on a platform not supported by any of the above, or if you are interested in getting access to intermediate IOS builds in support of SSM to EFT/Beta-test them, then please contact us (ssm-support@cisco.com).

 
• Cisco IOS 12.1T, 12.1E and 12.0S do each support a specific range of Cisco routers platforms. Please see the Cisco IOS Software Download page on CCO to see which platforms are supported. Cisco IOS 12.2 will be supported on the majority of Cisco router platforms and will include all features from IOS 12.1(5)T, and thus SSM and IGMPv3. Cisco IOS 12.1(5)T will be the last maintenance release of 12.1T before 12.2(1). Further enhancements to SSM related features beyond bug-fixes will then go into Cisco IOS 12.2T.

Application with support for IGMPv3

• Vic / Vat

Source diffs for vic & vat for IGMPv3 and binaries for FreeBSD4. Please see videolab.uoregon.edu/projects.html for further information.
 
• MIM

MIM is an application to receive MPEG-1 streams according to RFC1889, RFC1890 and RFC2250. It is compatible with IP/TV sources sending MPEG1. MIM will hopefully support IGMPv3 shortly.

IGMP v3 stacks

• IGMPv3 for Linux from Sprint Labs

 
• IGMPv3 for FreeBSD from Wilbert de Graaf

 
• IGMPv3 implementations for other host operating systems are in development but availability has not yet been publicly announced.

Host Side IGMP Library (HSIL) for IGMP v3lite

• IGMP v3lite is the Cisco transition solution for application developers to support SSM in applications with an IGMP v3 API even if the hosts operating system does not yet support IGMP v3. In addition, compiling an application with IGMP v3lite will allow an application to utilize IGMP v3 in the host operating system if it is available, and to use the IGMP v3lite transition mechanism otherwise.

 

 
 
 

To use IGMP v3lite, you need the host operating system Host Side IGMP Library (HSIL). It is available for free download from Talarian:

http://www.talarian.com/products/multicastlite/index.shtml

Currently, the HSIL is available for Microsoft Windows (95*,98*,NT,...) operating systems. If you are interested in the HSIL for other operating systems, please contact us at at ssm-support@cisco.com.

URD scripts

• URD-CGI Script from University Oregon

A URD CGI script is a CGI script to be run on a webserver announcing channels in the SSM range. The URD-CGI script generates we-pages that contain both the URD-URLs needed to trigger the URD function at the receiver host side, but also the links to start the applications on the receiver host.

• URD enabled content web page at videolab.uoregon.edu

The University of Oregon is providing several Audio/Video streams sourced into the SSM range from this URD enabled web page, and it also has links to SSM channels from other sources.

• videolab.uoregon.edu

Homepage of the University of Oregon for a variety of SSM and IP Multicast related resources: SSM Software, SSM content, SSM links and further IP Multicast information.
 
• SSM Address Usage Monitor

Monitoring the Usage of SSM range address in the Internet. Part of the MANTRA system.

"You are lost in a twisty little maze of e-mail addresses"
           - Unknown

Cisco IOS specific contact addresses

• ssm-support@cisco.com

This is the direct mail alias to reach Cisco engineering and deployment staff supporting SSM. Please use this address to get in contact with us or for direct support questions about SSM. We would especially like to hear from you if you have (or know) SSM host stack software, applications, content or other SSM resources that we have not listed on this page.
 
• ssm-announce@cisco.com

This announcement alias is used to distribute information about intermediate SSM image builds and other EFT and early deployment related information to interested customers. Please contact us (ssm-support@cisco.com), if you are interest to be put onto this mailing list.

• cisco-ssm@external.cisco.com

This is an open discussion forum for (application) developers, customers and users of SSM solutions. Cisco engineering and deployment staff will on a best effort base answer questions about SSM in Cisco IOS on this forum. Please consider subscribing to this forum especially if you are interested in using IGMP v3lite or URD in applications or services.
To subscribe to this mailing list, please send an email with "subscribe cisco-ssm" in the body to mailer@cisco.com. There is currently no archive for this mailing list.

Non-Cisco specific SSM contact information

• tac@cisco.com

If you are a Cisco customer and have a support contract through which you will have access to the Cisco TAC: For support questions related to Cisco IOS software  released on CCO you should open a support case on the TAC, to allow your request to be tracked and processed reliably and timely and to give it the requested priority.
 
• ssm-interest@external.cisco.com

This is the mailing list of the SSM Working Group of the IETF. This mailing list is intended for discussions about the elements of SSM that are to be standardized in the IETF. Please see the Charter page of the SSM Working Group for further information. The inofficial archive of this mailing list can be found at http://www.aciri.org/fenner/mcast/ssm/html-archive/.

Note: the standardization of IGMPv3 in the IETF takes place in the Inter Domain Multicast Routing Working Group (IGMP-WG) of the IETF. Please check out the Charter page of the IDMR-WG if you are interested in that.
 

• Please see the main IP Multicast Homepage for further contact or support information.