The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
The following are the prerequisites for configuring CGMP:
The following are the restrictions for CGMP:
This software release provides Cisco Group Management Protocol or CGMP-server support on your switch; no client-side functionality is provided. The switch serves as a CGMP server for devices that do not support IGMP snooping but have CGMP-client functionality.
CGMP is a protocol used on Cisco routers and multilayer switches connected to Layer 2 Catalyst switches to perform tasks similar to those performed by IGMP. CGMP permits Layer 2 group membership information to be communicated from the CGMP server to the switch. The switch can then learn on which interfaces multicast members reside instead of flooding multicast traffic to all switch interfaces. (IGMP snooping is another method to constrain the flooding of multicast packets.)
CGMP is necessary because the Layer 2 switch cannot distinguish between IP multicast data packets and IGMP report messages, which are both at the MAC level and are addressed to the same group address.
The switch serves as a CGMP server for devices that do not support IGMP snooping but have CGMP client functionality. CGMP is a protocol used on Cisco routers and multilayer switches connected to Layer 2 Catalyst switches to perform tasks similar to those performed by IGMP. CGMP is necessary because the Layer 2 switch cannot distinguish between IP multicast data packets and IGMP report messages, which are both at the MAC level and are addressed to the same group address.
When multiple Cisco CGMP-capable devices are connected to a switched network and the ip cgmp proxy command is needed, we recommend that all devices be configured with the same CGMP option and have precedence for becoming the IGMP querier over non-Cisco routers.
You can display specific statistics, such as the contents of IP routing tables, caches, and databases.
Note |
This release does not support per-route statistics. |
You can display information to learn resource usage and solve network problems. You can also display information about node reachability and discover the routing path that packets of your device are taking through the network.
Command |
Purpose |
---|---|
show ip igmp groups [ group-name | group-address | type number] |
Displays the multicast groups that are directly connected to the switch and that were learned through IGMP. |
show ip mpacket [ source-address | name] [ group-address | name] [ detail] |
|
show ip mroute [ group-name | group-address] [ source] [ summary] [ count] [ active kbps] |
|
Displays information about interfaces configured for PIM. This command is available in all software images. |
|
Lists the PIM neighbors discovered by the switch. This command is available in all software images. |
|
Displays the RP routers associated with a sparse-mode multicast group. This command is available in all software images. |
|
Displays how the switch is doing Reverse-Path Forwarding (that is, from the unicast routing table, DVMRP routing table, or static mroutes). |
|
Displays the Session Announcement Protocol (SAP) Version 2 cache. |
You can configure the following for your IP multicast configuration:
Related Topic | Document Title |
---|---|
For complete syntax and usage information for the commands used in this book. |
Catalyst 2960-XR Switch IP Multicast Command Reference |
Standard/RFC | Title |
---|---|
— |
— |
MIB | MIBs Link |
---|---|
All supported MIBs for this release. |
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: |
Description | Link |
---|---|
The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies. To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds. Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. |
Release | Modification |
---|---|
Cisco IOS 15.0(2)EX1 |
This feature was introduced. |