If your setup is similar to the one shown here, and you want to propagate DVMRP routes through the domain, configure the ip dvmrp unicast-routing command on the serial0 interfaces of Routers A and B. Multiprotocol Border Gateway Protocol MBGP is a basic method to carry two sets of routes: one set for unicast routing and one set for multicast routing. MBGP provides the control necessary to decide where multicast packets are allowed to flow. PIM uses the routes associated with multicast routing in order to build data distribution trees.
PIM is still needed in order to forward the multicast packets. If your unicast and multicast topologies are congruent for example, they are going over the same link , the primary difference in the configuration is with the nlri unicast multicast command. An example is shown here:. MSDP allows domains to discover multicast sources from other domains.
The ip pim neighbor-filter command is needed so that Router 1 does not recognize Router 2 as a PIM neighbor. If you configure Router 1 in sparse mode, the neighbor filter is unnecessary. Router 2 must not run in sparse mode. When in dense mode, the stub multicast sources can flood to the backbone routers.
Unidirectional Link Routing UDLR provides a method for forwarding multicast packets over a unidirectional satellite link to stub networks that have a back channel. This is similar to stub multicast routing.
Without this feature, the uplink router is not able to dynamically learn which IP multicast group addresses to forward over the unidirectional link, because the downlink router cannot send anything back. In order to configure a BSR, follow these steps:.
It is recommended but not required that hash-mask-Len be identical across all candidate BSRs. In order to avoid single point of failure, you can configure more than one router in a domain as candidate BSRs. In order to serve as candidate BSRs, the routers must be connected and be in the backbone of the network, instead of in the dialup area of the network. Configure candidate RP routers. This example shows a candidate RP, on the interface ethernet0, for the entire admin-scope address range:.
Pragmatic General Multicast PGM is a reliable multicast transport protocol for applications that require ordered, duplicate-free, multicast data delivery from multiple sources to multiple receivers. PGM guarantees that a receiver in the group either receives all data packets from transmissions and retransmissions or can detect unrecoverable data packet loss.
There are no PGM global commands. PGM is configured per interface with the ip pgm command. You must enable Multicast routing on the router with PIM on the interface. Multicast Routing Monitor MRM facilitates automated fault detection in a large multicast routing infrastructure.
The RPF check is performed differently for each:. Table shows the default multicast routing configuration. The Cisco PIMv2 implementation provides interoperability and transition between Version 1 and Version 2, although there might be some minor problems. You can upgrade to PIMv2 incrementally. PIM Versions 1 and 2 can be configured on different routers and multilayer switches within one network. Internally, all routers and multilayer switches on a shared media network must run the same PIM version.
We recommend that you use PIMv2. To ease the transition to PIMv2, we have these recommendations:. For more information, see the "Configuring Auto-RP" section. There are two approaches to using PIMv2. You can use Version 2 exclusively in your network or migrate to Version 2 by employing a mixed PIM version environment.
Then the software can forward multicast packets, and the switch can populate its multicast routing table. You can configure an interface to be in PIM dense mode, sparse mode, or sparse-dense mode. The switch populates its multicast routing table and forwards multicast packets it receives from its directly connected LANs according to the mode setting. Note If you enable PIM on multiple interfaces and most of these interfaces are not part of the outgoing interface list, when IGMP snooping is disabled the outgoing interface might not be able to sustain line rate for multicast traffic because of the extra, unnecessary replication.
In populating the multicast routing table, dense-mode interfaces are always added to the table. Sparse-mode interfaces are added to the table only when periodic join messages are received from downstream devices or when there is a directly connected member on the interface.
If so, the packets are encapsulated and sent toward the RP. When no RP is known, the packet is flooded in a dense-mode fashion. If the multicast traffic from a specific source is sufficient, the receiver's first-hop router might send join messages toward the source to build a source-based distribution tree. By default, multicast routing is disabled, and there is no default mode setting. This procedure is required. Specify the Layer 3 interface on which you want to enable multicast routing, and enter interface configuration mode.
These interfaces must have IP addresses assigned to them. For more information, see the "Configuring Layer 3 Interfaces" section. The interface returns to Version 2 mode after all Version 1 neighbors are shut down or upgraded. If you configure sparse-mode, you must also configure an RP. For more information, see the "Configuring a Rendezvous Point" section. Sparse-dense-mode is the recommended setting. To disable multicasting, use the no ip multicast-routing distributed global configuration command.
To return to the default PIM version, use the no ip pim version interface configuration command. To disable PIM on an interface, use the no ip pim interface configuration command. The PIM Stub routing feature supports multicast routing between the distribution layer and the access layer. You must also have PIM mode dense-mode, sparse-mode, or dense-sparse-mode configured on the uplink interface of the stub router. You must configure unicast stub routing to assist the PIM stub router behavior.
The PIM protocol is not supported in access domains. This procedure is optional. Specify the interface on which you want to enable PIM stub routing, and enter interface configuration mode.
To disable PIM stub routing on an interface, use the no ip pim passive interface configuration command. In this example, IP multicast routing is enabled, Switch A PIM uplink port 25 is configured as a routed uplink port with spare-dense-mode enabled.
This section describes how to configure source-specific multicast SSM. To locate documentation for other commands that appear in this chapter, use the command reference master index, or search online. The SSM feature is an extension of IP multicast in which datagram traffic is forwarded to receivers from only those multicast sources that the receivers have explicitly joined.
SSM is a datagram delivery model that best supports one-to-many applications, also known as broadcast applications. SSM is a core networking technology for the Cisco implementation of IP multicast solutions targeted for audio and video broadcast application environments.
The switch supports these components that support the implementation of SSM:. For example, with ISM, the network must maintain knowledge about which hosts in the network are actively sending multicast traffic. The ISM service consists of the delivery of IP datagrams from any source to a group of receivers called the multicast host group.
The datagram traffic for the multicast host group consists of datagrams with an arbitrary IP unicast source address S and the multicast group address G as the IP destination address. Systems receive this traffic by becoming members of the host group. Membership in a host group simply requires signalling the host group through IGMP version 1, 2, or 3.
However, in SSM, receivers must subscribe or unsubscribe to S, G channels to receive or not receive traffic from specific sources. In other words, receivers can receive traffic only from S, G channels to which they are subscribed, whereas in ISM, receivers need not know the IP addresses of sources from which they receive their traffic. The proposed standard approach for channel subscription signalling use IGMP include mode membership reports, which are supported only in IGMP version 3.
When an SSM range is defined, existing IP multicast receiver applications do not receive any traffic when they try to use an address in the SSM range unless the application is modified to use an explicit S, G channel subscription. Routers that are not directly connected to receivers do not require support for SSM. This configuration has the following effects:.
Incoming messages related to RPT operations are ignored or rejected, and incoming PIM register messages are immediately answered with register-stop messages. In IGMPv3, hosts signal membership to last hop routers of multicast groups. Hosts can signal group membership with filtering capabilities with respect to sources. A host can either signal that it wants to receive traffic from all sources sending to a group except for some specific sources called exclude mode , or that it wants to receive traffic only from some specific sources sending to the group called include mode.
In ISM, both exclude and include mode reports are applicable. In SSM, only include mode reports are accepted by the last-hop router. Exclude mode reports are ignored.
Therefore, enabling SSM in a network can cause problems for existing applications if they use addresses within the designated SSM range. Address management is still necessary to some degree when SSM is used with Layer 2 switching mechanisms. If different receivers in a switched network request different S, G channels sharing the same group, they do not benefit from these existing mechanisms.
Instead, both receivers receive all S, G channel traffic and filter out the unwanted traffic on input. Because SSM can re-use the group addresses in the SSM range for many independent applications, this situation can lead to decreased traffic filtering in a switched network. For this reason, it is important to use random IP addresses from the SSM range for an application to minimize the chance for re-use of a single address within the SSM range between different applications.
For example, an application service providing a set of television channels should, even with SSM, use a different group for each television S, G channel. This setup guarantees that multiple receivers to different channels within the same application service never experience traffic aliasing in networks that include Layer 2 switches. Therefore, as long as receivers send S, G subscriptions, the shortest path tree SPT state from the receivers to the source is maintained, even if the source does not send traffic for longer periods of time or even never.
This case is opposite to PIM-SM, where S, G state is maintained only if the source is sending traffic and receivers are joining the group. Select an interface that is connected to hosts on which IGMPv3 can be enabled, and enter the interface configuration mode. Enable PIM on an interface.
You must use either sparse mode or sparse-dense mode. Enable IGMPv3 on this interface. Display whether a multicast group supports SSM service or whether a source-specific host report was received. If you do not already have a DNS server running, you need to install one. You can use a product such as Cisco Network Registrar. Because SSM mapping takes a group join from a host and identifies this group with an application associated with one or more sources, it can only support one such application per group.
SSM mapping does not support these IGMPv3 group reports, and the router does not correctly associate sources with these reports. A single server can send multiple TV channels, but each to a different group. When SSM mapping is configured, if a router receives an IGMPv1 or IGMPv2 membership report for a particular group, the router translates this report into one or more channel memberships for the well-known sources associated with this group.
SSM mapping enables the last hop router to determine the source addresses either by a statically configured table on the router or through a DNS server. When the statically configured table or the DNS mapping changes, the router leaves the current sources associated with the joined groups. With static SSM mapping, you can configure the last hop router to use a static map to determine the sources that are sending to groups. Then you can map the groups permitted by those ACLs to sources by using the ip igmp static ssm-map global configuration command.
The router looks up IP address resource records and uses them as the source addresses associated with this group. SSM mapping supports up to 20 sources for each group. The router joins all sources configured for a group see Figure The SSM mapping mechanism that enables the last hop router to join multiple sources for a group can provide source redundancy for a TV broadcast. In this context, the last hop router provides redundancy using SSM mapping to simultaneously join two video sources for the same TV channel.
However, to prevent the last hop router from duplicating the video traffic, the video sources must use a server-side switchover mechanism. One video source is active, and the other backup video source is passive. The passive source waits until an active source failure is detected before sending the video traffic for the TV channel. Thus, the server-side switchover mechanism ensures that only one of the servers is actively sending video traffic for the TV channel.
The ACL supplied for access-list defines the groups to be mapped to the source IP address entered for the source-address. Note You can configure additional static SSM mappings. If additional SSM mappings are configured and the router receives an IGMPv1 or IGMPv2 membership report for a group in the SSM range, the switch determines the source addresses associated with the group by using each configured ip igmp ssm-map static command.
The switch associates up to 20 sources per group. Only the no form of this command is saved to the running configuration. By default, the switch uses the ip-addr. Specify the address of one or more name servers to use for name and address resolution. Repeat Step 5 to configure additional DNS servers for redundancy, if required.
Select an interface on which to statically forward traffic for a multicast group using SSM mapping, and enter interface configuration mode. Use this command if you want to statically forward SSM traffic for certain groups. Display the multicast groups with receivers that are directly connected to the router and that were learned through IGMP.
Display the default domain name, the style of name lookup service, a list of name server hosts, and the cached list of hostnames and addresses. You must have an RP if the interface is in sparse-dense mode and if you want to treat the group as a sparse group. You can use several methods, as described in these sections:. This section explains how to manually configure an RP. Senders of multicast traffic announce their existence through register messages received from the source's first-hop router designated router and forwarded to the RP.
Receivers of multicast packets use RPs to join a multicast group by using explicit join messages. RPs are not members of the multicast group; rather, they serve as a meeting place for multicast sources and group members. You can configure a single RP for multiple groups defined by an access list.
If there is no RP configured for a group, the multilayer switch treats the group as dense and uses the dense-mode PIM techniques. If there is no RP configured for a group, the switch treats the group as dense, using the dense-mode PIM techniques. The access-list conditions specify for which groups the device is an RP.
If no access list is configured, the RP is used for all groups. Create a standard access list, repeating the command as many times as necessary. The permit keyword permits access if the conditions are matched. Place ones in the bit positions that you want to ignore. Recall that the access list is always terminated by an implicit deny statement for everything. To remove an RP address, use the no ip pim rp-address ip-address [ access-list-number ] [ override ] global configuration command.
This example shows how to configure the address of the RP to It has these benefits:. For overview information, see the "Auto-RP" section. If you are setting up Auto-RP in a new internetwork, you do not need a default RP because you configure all the interfaces for sparse-dense mode.
This section contains some suggestions for the initial deployment of Auto-RP into an existing sparse-mode cloud to minimize disruption of the existing multicast infrastructure. It was previously configured with the ip pim rp-address global configuration command. The selected RP should have good connectivity and be available across the network.
Use this RP for the global groups for example Do not reconfigure the group address range that this RP serves. Assume that it is desirable to use a second RP for the local groups. Valid interfaces include physical ports, port channels, and VLANs. Enter a hop count that is high enough so that the RP-announce messages reach all mapping agents in the network.
There is no default setting. The range is 1 to The default is 60 seconds. Find a switch whose connectivity is not likely to be interrupted, and assign it the role of RP-mapping agent. For scope ttl , specify the time-to-live value in hops to limit the RP discovery packets.
All devices within the hop count from the source device receive the Auto-RP discovery messages. These messages tell other devices which group-to-RP mapping to use to avoid conflicts such as overlapping group-to-RP ranges. To remove the PIM device configured as the candidate RP, use the no ip pim send-rp-announce interface-id global configuration command.
To remove the switch as the RP-mapping agent, use the no ip pim send-rp-discovery global configuration command. This example shows how to send RP announcements out all PIM-enabled interfaces for a maximum of 31 hops. The IP address of port 1 is the RP. Access list 5 describes the group for which this switch serves as RP:. Find whether the ip pim accept-rp command was previously configured throughout the network by using the show running-config privileged EXEC command.
If the ip pim accept-rp command is not configured on any device, this problem can be addressed later. In those routers or multilayer switches already configured with the ip pim accept-rp command, you must enter the command again to accept the newly advertised RP.
To accept all RPs advertised with Auto-RP and reject all other RPs by default, use the ip pim accept-rp auto-rp global configuration command. If all interfaces are in sparse mode, use a default-configured RP to support the two well-known groups Auto-RP uses these two well-known groups to collect and distribute RP-mapping information.
When this is the case and the ip pim accept-rp auto-rp command is configured, another ip pim accept-rp command accepting the RP must be configured as follows:. You can add configuration commands to the mapping agents to prevent a maliciously configured router from masquerading as a candidate RP and causing problems.
Enter this command on each mapping agent in the network. Without this command, all incoming RP-announce messages are accepted by default. For rp-list access-list-number , configure an access list of candidate RP addresses that, if permitted, is accepted for the group ranges supplied in the group-list access-list-number variable. If this variable is omitted, the filter applies to all multicast groups. If more than one mapping agent is used, the filters must be consistent across all mapping agents to ensure that no conflicts occur in the Group-to-RP mapping information.
To remove a filter on incoming RP announcement messages, use the no ip pim rp-announce-filter rp-list access-list-number [ group-list access-list-number ] global configuration command. You can also display information about node reachability and discover the routing path that packets of your device are taking through the network. Displays the multicast groups that are directly connected to the switch and that were learned through IGMP.
Displays the contents of the IP multicast routing table. Displays information about interfaces configured for PIM. This command is available in all software images. Lists the PIM neighbors discovered by the switch. Displays the RP routers associated with a sparse-mode multicast group. Queries a multicast router or multilayer switch about which neighboring multicast devices are peering with it. Traces the path from a source to a destination branch for a multicast distribution tree for a given group.
This example shows how to set up a boundary for all administratively-scoped addresses:. The software answers mrinfo requests sent by mrouted systems and Cisco routers and multilayer switches. The software returns information about neighbors through DVMRP tunnels and all the routed interfaces. This information includes the metric always set to 1 , the configured TTL threshold, the status of the interface, and various flags. You can also use the mrinfo privileged EXEC command to query the router or switch itself, as in this example:.
Routing Command Reference Catalyst Switches. To help you research and resolve system error messages in this release, use the Error Message Decoder tool. The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.
Access to most tools on the Cisco Support website requires a Cisco. Finding Feature Information Your software release may not support all the features documented in this module. Prerequisites for Configuring IP Multicast Routing The following are the prerequisites for configuring IP multicast routing: To use the IP multicast routing feature on the switch , the switch or active switch must be running the IP Services feature set.
After performing these tasks, the switch can then forward multicast packets and can populate its multicast routing table.
Layer 3 IPv6 multicast routing is not supported on the switch. High-availability support for Layer 3 multicast routing is not supported. You cannot have a switch stack containing a mix of Catalyst and Catalyst switches. Information About IP Multicast Routing IP multicasting is an efficient way to use network resources, especially for bandwidth-intensive services such as audio and video.
Protocol-Independent Multicast PIM protocol is used among routers and multilayer switches to track which multicast packets to forward to each other and to their directly connected LANs.
Figure 1. IP Multicast Routing Protocols. The following figure shows where the Cisco-supported protocols for the switch operate within the IP multicast environment. It is responsible for: Forwarding multicast packets Registering with the MRIB to learn the entry and interface flags set by the control plane Handling data-driven events that must be sent to the control plane Maintaining counts, rates, and bytes of received, dropped, and forwarded multicast packets The MRIB is the communication channel between MRIB clients.
Multicast Group Concept Multicast is based on the concept of a group. Multicast Boundaries Administratively-scoped boundaries can be used to limit the forwarding of multicast traffic outside of a domain or subdomain. Note Multicast boundaries and TTL thresholds control the scoping of multicast domains; however, TTL thresholds are not supported by the switch.
Figure 2. Administratively-Scoped Boundaries. The following figure shows that Company XYZ has an administratively-scoped boundary set for the multicast address range This boundary prevents any multicast traffic in the range Similarly, the engineering and marketing departments have an administratively-scoped boundary of This boundary prevents multicast traffic in the range of Multicast Routing and Switch Stacks For all multicast routing protocols, the entire stack appears as a single router to the network and operates as a single multicast router.
In a switch stack, the active switch performs these functions: It is responsible for completing the IP multicast routing functions of the stack. It fully initializes and runs the IP multicast routing protocols. It builds and maintains the multicast routing table for the entire stack. It is responsible for distributing the multicast routing table to all stack members. The stack members perform these functions: They act as multicast routing standby devices and are ready to take over if there is a active switch failure.
If the active switch fails, all stack members delete their multicast routing tables. The newly elected active switch starts building the routing tables and distributes them to the stack members.
They do not build multicast routing tables. Instead, they use the multicast routing table that is distributed by the active switch. Default Multicast Routing Configuration This table describes the default multicast routing configuration for the switch. Note If you enable PIM on multiple interfaces, when most of these interfaces are not on the outgoing interface list, and IGMP snooping is disabled, the outgoing interface might not be able to sustain line rate for multicast traffic because of the extra replication.
This procedure is required. Note After you have enabled IP multicast routing by using the ip multicast-routing command, IPv4 multicast forwarding is enabled.
Static mroutes are similar to unicast static routes but differ in the following ways: Static mroutes are used to calculate RPF information, not to forward traffic. Static mroutes cannot be redistributed. This procedure is optional. Related Concepts Multicast Boundaries. Multicast Group Concept.
You can use any of the privileged EXEC commands in the following table to clear IP multicast caches, tables, and databases.
Displaying System and Network Statistics 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 use any of the privileged EXEC commands in the following table to display various routing statistics. Select —Group-based VRF select information.
Command parameters include: A. D —IP group address. WORD —Session name in double quotes. Example: Configuring an IP Multicast Boundary This example shows how to set up a boundary for all administratively-scoped addresses: Switch config access-list 1 deny Example: Responding to mrinfo Requests The software answers mrinfo requests sent by mrouted systems and Cisco routers and multilayer switches.
You can also use the mrinfo privileged EXEC command to query the router or switch itself, as in this example: Switch mrinfo Technical Assistance 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. Configuring IP Multicast Routing.
Multicast routing.
0コメント