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Table Of Contents
IP Multicast Multilayer Switching
Layer 2 Multicast Forwarding Table
Layer 3-Switched Multicast Packet Rewrite
Partially and Completely Switched Flows
IP Multicast MLS Network Topology
Router Configuration Restrictions
Access List Restrictions and Guidelines
Related Features and Technologies
Supported Standards, MIBs, and RFCs
Specifying a Management Interface
Monitoring and Maintaining IP Multicast MLS
Basic IP Multicast MLS Network
Operation Before IP Multicast MLS
Operation After IP Multicast MLS
Complex IP Multicast MLS Network
Operation Before IP Multicast MLS
Operation After IP Multicast MLS
Router A (MMLS-RP) Configuration
Router B (MMLS-RP) Configuration
Switch A (MMLS-SE) Configuration
mls rp ip multicast management-interface
IP Multicast Multilayer Switching
This feature module describes the IP multicast Multilayer Switching (MLS) feature. It includes the following sections:
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Supported Standards, MIBs, and RFCs
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Feature Overview
The IP multicast MLS feature provides high-performance, hardware-based, Layer 3 switching of IP multicast traffic for routers connected to Catalyst 5000 series LAN switches.
An IP multicast flow is a unidirectional sequence of packets between a multicast source and the members of a destination multicast group. Flows are based on the IP address of the source device and the destination IP multicast group address.
IP multicast MLS switches IP multicast data packet flows between IP subnets using advanced, application-specific integrated circuit (ASIC) switching hardware, thereby off-loading processor-intensive, multicast packet routing from network routers.
The packet forwarding function is moved onto the connected Layer 3 switch whenever a supported path exists between a source and members of a multicast group. Packets that do not have a supported path to reach their destinations are still forwarded in software by routers. Protocol Independent Multicast (PIM) is used for route determination.
IP Multicast MLS Components
An IP multicast MLS network topology has two components:
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Layer 2 Multicast Forwarding Table
The MMLS-SE uses the Layer 2 multicast forwarding table to determine on which ports Layer 2 multicast traffic should be forwarded (if any). The Layer 2 multicast forwarding table is populated by enabling CGMP, IGMP snooping, or GMRP on the switch. These entries map the destination multicast MAC address to outgoing switch ports for a given VLAN.
Layer 3 Multicast MLS Cache
The MMLS-SE maintains the Layer 3 MLS cache to identify individual IP multicast flows. Each entry is of the form {source IP, destination group IP, source VLAN}. The maximum MLS cache size is 128K and is shared by all MLS processes on the switch (such as IP unicast MLS and IPX MLS). However, if the total of cache entries exceeds 32K, there is increased probability that a flow will not be switched by the MMLS-SE and will get forwarded to the router.
The MMLS-SE populates the MLS cache using information learned from the routers participating in IP multicast MLS. The router and switch exchange information using the multicast Multilayer Switching Protocol (multicast MLSP).
Whenever the router receives traffic for a new flow, it updates its multicast routing table and forwards the new information to the MMLS-SE using multicast MLSP. In addition, if an entry in the multicast routing table is aged out, the router deletes the entry and forwards the updated information to the MMLS-SE.
The MLS cache contains flow information for all active multilayer switched flows. After the MLS cache is populated, multicast packets identified as belonging to an existing flow can be Layer 3-switched based on the cache entry for that flow. For each cache entry, the MMLS-SE maintains a list of outgoing interfaces for the destination IP multicast group. The MMLS-SE uses this list to determine on which VLANs traffic to a given multicast flow should be replicated.
IP Multicast MLS Flow Mask
IP multicast MLS supports a single flow mask, source-destination-vlan. The MMLS-SE maintains one multicast MLS cache entry for each {source IP, destination group IP, source VLAN}. The multicast source-destination-vlan flow mask differs from the IP unicast MLS source-destination-ip flow mask in that, for IP multicast MLS, the source VLAN is included as part of the entry. The source VLAN is the multicast Reverse Path Forwarding (RPF) interface for the multicast flow.
Layer 3-Switched Multicast Packet Rewrite
When a multicast packet is Layer 3-switched from a multicast source to a destination multicast group, the MMLS-SE performs a packet rewrite based on information learned from the MMLS-RP and stored in the multicast MLS cache.
For example, if Server A sends a multicast packet addressed to IP multicast group G1 and members of group G1 are on VLANs other than the source VLAN, the MMLS-SE must perform a packet rewrite when it replicates the traffic to the other VLANs (the switch also bridges the packet in the source VLAN).
When the MMLS-SE receives the multicast packet, it is formatted similarly to the sample that follows (only the important fields are shown):
Destination
Source
Destination
Source
TTL
Checksum
Data
Checksum
Group G1 MAC
Server A MAC
Group G1 IP
Server A IP
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calculation1
The MMLS-SE rewrites the packet as follows:
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The result is a rewritten IP multicast packet that appears to have been routed by the router. The MMLS-SE replicates the rewritten packet onto the appropriate destination VLANs, where it is forwarded to members of IP multicast group G1.
After the MMLS-SE performs the packet rewrite, the packet is formatted as follows:
Destination
Source
Destination
Source
TTL
Checksum
Data
Checksum
Group G1 MAC
MMLS-RP MAC
Group G1 IP
Server A IP
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calculation2
Partially and Completely Switched Flows
When at least one outgoing router interface for a given flow is multilayer switched, and at least one outgoing interface is not multilayer switched, that flow is considered partially switched. When a partially switched flow is created, all multicast traffic belonging to that flow still reaches the router and is software forwarded on those outgoing interfaces that are not multilayer switched.
A flow might be partially switched instead of completely switched in these situations:
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When all the outgoing router interfaces for a given flow are multilayer switched, and none of the above situations apply to the flow, that flow is considered completely switched. When a completely switched flow is created, the MMLS-SE prevents multicast traffic bridged on the source VLAN for that flow from reaching the MMLS-RP interface in that VLAN, reducing the load on the router.
One consequence of a completely switched flow is that the router cannot record multicast statistics for that flow. Therefore, the MMLS-SE periodically sends multicast packet and byte count statistics for all completely switched flows to the router using multicast MLSP. The router updates the corresponding multicast routing table entry and resets the expiration timer for that multicast route.
IP Multicast MLS Network Topology
IP multicast MLS requires specific network topologies to function correctly. In each of these topologies, the source traffic is received on the switch, traverses a trunk link to the router, and returns to the switch over the same trunk link to reach the destination group members. The basic topology consists of a switch and an internal or external router connected through an ISL or 802.1Q trunk link.
shows this basic configuration before and after IP multicast MLS is deployed (assuming a completely switched flow). The topology consists of a switch, a directly connected external router, and multiple IP subnetworks (VLANs).
The network in the upper diagram in does not have the IP multicast MLS feature enabled. Note the arrows from the router to each multicast group in each VLAN. In this case, the router must replicate the multicast data packets to the multiple VLANs. The router can be easily overwhelmed with forwarding and replicated multicast traffic if the input rate or the number of outgoing interfaces increases.
As shown in the lower diagram in , this potential problem is prevented by having the switch hardware forward the multicast data traffic. (Multicast control packets are still moving between the router and switch.)
Figure 1 Basic IP Multicast MLS Network Topology
Benefits
Improves Throughput
This feature improves the router's multicast Layer 3 forwarding and replication throughput.
Reduces Load on Router
If the router must replicate many multicast packets to many VLANs, it can be overwhelmed as the input rate and number of outgoing interfaces increase. Configuring the switch to replicate and forward the multicast flow reduces the demand on the router.
Provides IP Multicast Scalability
If you need high throughput of multicast traffic, install a Catalyst 5000 series switch and configure this feature. By reducing the load on your router, you can accommodate more multicast flows.
Provides Meaningful Flow Statistics
IP multicast MLS provides flow statistics that can be used to administer, plan, and troubleshoot networks.
Restrictions
You must also configure the Catalyst 5000 series switch in order for IP multicast MLS to function on the router.
The restrictions in the following sections apply to IP multicast MLS on the router:
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Router Configuration Restrictions
IP multicast MLS does not work on internal or external routers in the following situations:
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External Router Guidelines
Follow these guidelines when using an external router:
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Access List Restrictions and Guidelines
These restrictions apply when using access lists on interfaces participating in IP multicast MLS:
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For example, if the following input access list is applied to the RPF interface for a group of flows, no flows will be multilayer switched even though the second entry permits all IP traffic (because the protocol specified in the first entry is not ip):
Router(config)# access-list 101 permit udp any anyRouter(config)# access-list 101 permit ip any anyIf the following input access list is applied to the RPF interface for a group of flows, all flows except the {s1,g1} flow are multilayer switched (because the protocol specified in the entry for {s1, g1} is not ip):
Router(config)# access-list 101 permit udp s1 g1Router(config)# access-list 101 permit ip any anyUnsupported Features
If IP multicast MLS is enabled, IP accounting for the interface will not reflect accurate values.
Related Features and Technologies
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Related Documents
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Supported Platforms
The first five platforms listed are external routers; the last two platforms have internal routers:
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Supported Standards, MIBs, and RFCs
MIBs
No new or modified MIBs are supported by this feature.
For descriptions of supported MIBs and how to use MIBs, see the Cisco MIB web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.
RFCs
None
Standards
None
Prerequisites
The following prerequisites are necessary before MLS can function:
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Configuration Tasks
See the following sections for configuration tasks for IP multicast MLS. Each task in the list indicates whether it is optional or required.
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For examples of IP multicast MLS configurations, see the "Configuration Examples" section later in this document.
Enabling IP Multicast Routing
You must enable IP multicast routing globally on the MMLS-RPs before you can enable IP multicast MLS on router interfaces. To enable IP multicast routing on the router, use the following command:
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Enabling IP PIM
You must enable Protocol Independent Multicast (PIM) on the router interfaces connected to the switch before IP multicast MLS will function on those router interfaces. To do so, use the following commands:
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Router(config)# interface type number
Configures an interface.
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Router(config-if)# ip pim {dense-mode | sparse-mode | sparse-dense-mode}
Enables PIM on the interface.
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Enabling IP Multicast MLS
IP multicast MLS is enabled by default when you enable PIM on the interface. Perform this task only if you disabled IP multicast MLS and you want to reenable it. To enable IP multicast MLS on an interface, use the following command:
Specifying a Management Interface
When you enable IP multicast MLS, the subinterface (or VLAN interface) that has the lowest VLAN ID and is active (in the "up" state) is automatically selected as the management interface. The one-hop protocol Multilayer Switching Protocol (MLSP) is used between a router and a switch to pass messages about hardware-switched flows. MLSP packets are sent and received on the management interface. Typically, the interface in VLAN 1 is chosen (if that interface exists). Only one management interface is allowed on a single trunk link.
In most cases, we recommend that the management interface be determined by default. However, you can optionally specify a different router interface or subinterface as the management interface. We recommend using a subinterface with minimal data traffic so that multicast MLSP packets can be sent and received more quickly.
If the user-configured management interface goes down, the router uses the default interface (the active interface with the lowest VLAN ID) until the user-configured interface comes up again.
To change the default IP multicast MLS management interface, use the following command:
Router(config-if)# mls rp ip multicast management-interface
Configures an interface as the IP multicast MLS management interface.
Monitoring and Maintaining IP Multicast MLS
Configuration Examples
These sections contain example IP multicast MLS implementations. These examples include the switch configurations, although switch commands are not documented in this router publication. Refer to the Catalyst 5000 Command Reference for that information.
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Basic IP Multicast MLS Network
This example consists of these sections:
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Example Network Topology
shows a basic IP multicast MLS example network topology.
Figure 2 Basic IP Multicast MLS Example Network
The network is configured as follows:
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Operation Before IP Multicast MLS
Without IP multicast MLS, when the G1 source (on VLAN 10) sends traffic destined for IP multicast group G1, the switch forwards the traffic (based on the Layer 2 multicast forwarding table entry generated by the IGMP snooping, CGMP, or GMRP multicast service) to Host A on VLAN 10 and to the router subinterface in VLAN 10.
The router receives the multicast traffic on its incoming subinterface for VLAN 10, checks the multicast routing table, and replicates the traffic to the outgoing subinterfaces for VLANs 20 and 30. The switch receives the traffic on VLANs 20 and 30 and forwards the traffic received on these VLANs to the appropriate switch ports, again based on the contents of the Layer 2 multicast forwarding table.
Operation After IP Multicast MLS
After IP multicast MLS is implemented, when the G1 source sends traffic destined for multicast group G1, the MMLS-SE checks its Layer 3 multicast MLS cache and recognizes that the traffic belongs to a multicast MLS flow. The MMLS-SE forwards the traffic to Host A on VLAN 10 based on the multicast forwarding table, but does not forward the traffic to the router subinterface in VLAN 10 (assuming a completely switched flow).
For each multicast MLS cache entry, the switch maintains a list of outgoing interfaces for the destination IP multicast group. The switch replicates the traffic on the appropriate outgoing interfaces (VLANs 20 and 30) and then forwards the traffic on each VLAN to the destination hosts (using the Layer 2 multicast forwarding table). The switch performs a packet rewrite for the replicated traffic so that the packets appear to have been routed by the appropriate router subinterface.
If not all the router subinterfaces are eligible to participate in IP multicast MLS, the switch must forward the multicast traffic to the router subinterface in the source VLAN (in this case, VLAN 10). In this situation, on those subinterfaces that are ineligible, the router performs multicast forwarding and replication in software, in the usual manner. On those subinterfaces that are eligible, the switch performs multilayer switching.
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Router Configuration
The following is an example configuration of IP multicast MLS on the router:
ip multicast-routinginterface fastethernet2/0.10encapsulation isl 10ip address 10.1.10.1 255.255.255.0ip pim dense-modeinterface fastethernet2/0.20encapsulation isl 20ip address 10.1.20.1 255.255.255.0ip pim dense-modeinterface fastethernet2/0.30encapsulation isl 30ip address 10.1.30.1 255.255.255.0ip pim dense-modemls rp ip multicast management-interfaceYou will receive the following message informing you that you changed the management interface:
Warning: MLS Multicast management interface is now Fa2/0.30Switch Configuration
The following example shows how to configure the switch (MMLS-SE):
Console> (enable) set trunk 1/2 on islPort(s) 1/2 trunk mode set to on.Port(s) 1/2 trunk type set to isl.Console> (enable) set igmp enableIGMP feature for IP multicast enabledConsole> (enable) set mls multicast enableMultilayer Switching for Multicast is enabled for this device.Console> (enable) set mls multicast include 10.1.10.1Multilayer switching for multicast is enabled for router 10.1.10.1.Complex IP Multicast MLS Network
This example consists of these sections:
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Example Network Topology
shows a more complex IP multicast MLS example network topology.
Figure 3 Complex IP Multicast MLS Example Network
The network is configured as follows:
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Operation Before IP Multicast MLS
Without IP multicast MLS, when Server A (on VLAN 10) sends traffic destined for IP multicast group G1, Switch B forwards the traffic (based on the Layer 2 multicast forwarding table entry) to Host A on VLAN 10 and to Switch A. Switch A forwards the traffic to the Router A and Router B subinterfaces in VLAN 10.
Router A receives the multicast traffic on its incoming subinterface for VLAN 10, checks the multicast routing table, and replicates the traffic to the outgoing subinterface for VLAN 20. Router B receives the multicast traffic on its incoming interface for VLAN 10, checks the multicast routing table, and replicates the traffic to the outgoing subinterface for VLAN 30.
Switch A receives the traffic on VLANs 20 and 30. Switch A forwards VLAN 20 traffic to the appropriate switch ports (in this case, to Host C), based on the contents of the Layer 2 multicast forwarding table. Switch A forwards the VLAN 30 traffic to Switch C.
Switch C receives the VLAN 30 traffic and forwards it to the appropriate switch ports (in this case, Hosts D and E) using the multicast forwarding table.
Operation After IP Multicast MLS
After IP multicast MLS is implemented, when Server A sends traffic destined for multicast group G1, Switch B forwards the traffic (based on the Layer 2 multicast forwarding table entry) to Host A on VLAN 10 and to Switch A.
Switch A checks its Layer 3 multicast MLS cache and recognizes that the traffic belongs to a multicast MLS flow. Switch A does not forward the traffic to the router subinterfaces in VLAN 10 (assuming a completely switched flow). Instead, Switch A replicates the traffic on the appropriate outgoing interfaces (VLANs 20 and 30).
VLAN 20 traffic is forwarded to Host C and VLAN 30 traffic is forwarded to Switch C (based on the contents of the Layer 2 multicast forwarding table). The switch performs a packet rewrite for the replicated traffic so that the packets appear to have been routed by the appropriate router subinterface.
Switch C receives the VLAN 30 traffic and forwards it to the appropriate switch ports (in this case, Hosts D and E) using the multicast forwarding table.
If not all the router subinterfaces are eligible to participate in IP multicast MLS, the switch must forward the multicast traffic to the router subinterfaces in the source VLAN (in this case, VLAN 10). In this situation, on those subinterfaces that are ineligible, the routers perform multicast forwarding and replication in software in the usual manner. On those subinterfaces that are eligible, the switch performs multilayer switching.
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Router A (MMLS-RP) Configuration
ip multicast-routinginterface fastethernet1/0.1encapsulation isl 1ip address 172.20.1.1 255.255.255.0interface fastethernet1/0.10encapsulation isl 10ip address 172.20.10.1 255.255.255.0ip pim dense-modeinterface fastethernet1/0.20encapsulation isl 20ip address 172.20.20.1 255.255.255.0ip pim dense-modeRouter B (MMLS-RP) Configuration
ip multicast-routinginterface fastethernet1/0.1encapsulation isl 1ip address 172.20.1.2 255.255.255.0interface fastethernet2/0.10encapsulation isl 10ip address 172.20.10.100 255.255.255.0ip pim dense-modeinterface fastethernet2/0.30encapsulation isl 30ip address 172.20.30.100 255.255.255.0ip pim dense-modeSwitch A (MMLS-SE) Configuration
Console> (enable) set vlan 10Vlan 10 configuration successfulConsole> (enable) set vlan 20Vlan 20 configuration successfulConsole> (enable) set vlan 30Vlan 30 configuration successfulConsole> (enable) set trunk 1/1 on islPort(s) 1/1 trunk mode set to on.Port(s) 1/1 trunk type set to isl.Console> (enable) set trunk 1/2 on islPort(s) 1/2 trunk mode set to on.Port(s) 1/2 trunk type set to isl.Console> (enable) set trunk 1/3 desirable islPort(s) 1/3 trunk mode set to desirable.Port(s) 1/3 trunk type set to isl.Console> (enable) set trunk 1/4 desirable islPort(s) 1/4 trunk mode set to desirable.Port(s) 1/4 trunk type set to isl.Console> (enable) set igmp enableIGMP feature for IP multicast enabledConsole> (enable) set mls multicast enableMultilayer Switching for Multicast is enabled for this device.Console> (enable) set mls multicast include 172.20.10.1Multilayer switching for multicast is enabled for router 172.20.10.1.Console> (enable) set mls multicast include 172.20.10.100Multilayer switching for multicast is enabled for router 172.20.10.100.Console> (enable)Switch B Configuration
The following example shows how to configure Switch B (assuming VLAN Trunking Protocol [VTP] is used for VLAN management):
Console> (enable) set igmp enableIGMP feature for IP multicast enabledConsole> (enable)Switch C Configuration
The following example shows how to configure Switch C (assuming VTP is used for VLAN management):
Console> (enable) set igmp enableIGMP feature for IP multicast enabledConsole> (enable)Command Reference
This section documents new or modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command reference publications and the Catalyst 5000 Software Configuration Guide and Catalyst 5000 Command Reference, Release 5.1.
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In Cisco IOS Release 12.0(1)T or later, you can search and filter the output for show and more commands. This functionality is useful when you need to sort through large amounts of output, or if you want to exclude output that you do not need to see.
To use this functionality, enter a show or more command followed by the "pipe" character (|), one of the keywords begin, include, or exclude, and an expression that you want to search or filter on:
command | {begin | include | exclude} regular-expression
Following is an example of the show atm vc command in which you want the command output to begin with the first line where the expression "PeakRate" appears:
show atm vc | begin PeakRate
For more information on the search and filter functionality, refer to the Cisco IOS Release 12.0(1)T feature module entitled CLI String Search.
clear ip mroute
To delete entries from the IP multicast routing table, use the clear ip mroute EXEC command.
clear ip mroute {* | group [source]}
Syntax Description
Command Modes
EXEC
Command History
Examples
The following example deletes all entries from the IP multicast routing table:
clear ip mroute *The following example deletes from the IP multicast routing table all sources on the 10.3.0.0 subnet that are sending to the multicast group 224.2.205.42. Note that this example deletes all sources on network 10.3, not individual sources.
clear ip mroute 224.2.205.42 10.3.0.0Related Commands
ip host
Statically maps a host name to an IP address.
Enables IP multicast MLS.
show ip mroute
Displays the contents of the IP multicast routing table.
ip multicast-routing
To enable IP multicast routing, use the ip multicast-routing global configuration command. To disable IP multicast routing, use the no form of this command.
ip multicast-routing
no ip multicast-routingSyntax Description
This command has no arguments or keywords.
Defaults
Disabled
Command Modes
Global configuration
Command History
Usage Guidelines
When IP multicast routing is disabled, the Cisco IOS software does not forward any multicast packets.
Examples
The following example enables IP multicast routing:
ip multicast-routingRelated Commands
mls rp ip multicast
To enable IP multicast Multilayer Switching (hardware switching) on an external or internal router in conjunction with Layer 3 switching hardware for the Catalyst 5000, use the mls rp ip multicast interface configuration command. Use the no form of the command to disable IP multicast Multilayer Switching (MLS) on the interface or VLAN.
mls rp ip multicast
no mls rp ip multicastSyntax Description
This command has no arguments or keywords.
Defaults
Enabled
Command Modes
Interface configuration
Command History
Usage Guidelines
This feature is available only on specific router platforms connected to a Catalyst 5000 switch. Use this feature to reduce multicast load on the router. The switch will perform the multicast packet replication and forwarding.
IP multicast MLS is enabled by default on an interface once IP multicast routing and PIM are enabled.
Examples
The following example disables IP multicast MLS:
interface fastethernet1/0.1 no mls rp ip multicastRelated Commands
Assigns a management interface other than the default.
Enables complete flows for IP multicast MLS.
Displays hardware-switched multicast flow information about IP multicast MLS.
mls rp ip multicast management-interface
To assign a different interface (other than the default) to act as the management interface for Multilayer Switching Protocol (MLSP) , use the mls rp ip multicast management-interface interface configuration command. Use the no form of the command to restore the default interface as the management interface.
mls rp ip multicast management-interface
no mls rp ip multicast management-interfaceSyntax Description
This command has no arguments or keywords.
Defaults
When IP multicast MLS is enabled, the subinterface (or VLAN interface) that has the lowest VLAN ID and is active (in the "up" state) is automatically selected as the management interface.
Command Modes
Interface configuration
Command History
Usage Guidelines
When you enable IP multicast MLS, the subinterface (or VLAN interface) that has the lowest VLAN ID and is active (in the "up" state) is automatically selected as the management interface. The one-hop protocol Multilayer Switching Protocol (MLSP) is used between a router and a switch to pass messages about hardware-switched flows. MLSP packets are sent and received on the management interface. Typically, the interface in VLAN 1 is chosen (if that interface exists). Only one management interface is allowed on a single trunk link.
In most cases, we recommend that the management interface be determined by default. However, you can optionally use this command to specify a different router interface or subinterface as the management interface. We recommend using a subinterface with minimal data traffic so that multicast MLSP packets can be transmitted and received more quickly.
If the user-configured management interface goes down, the router uses the default interface (the active interface with the lowest VLAN ID) until the user-configured interface comes up again.
Examples
The following example configures the Fast Ethernet interface as the management interface:
interface fastethernet1/0.1 mls rp ip multicast management-interfaceRelated Commands
show ip mroute
To display the contents of the IP multicast routing table, use the show ip mroute EXEC command.
show ip mroute [group-name | group-address] [source] [summary] [count] [active kbps]
Syntax Description
Default
The show ip mroute command displays all groups and sources.
The show ip mroute active command displays all sources sending at a rate greater than or equal to 4 kbps.Command Modes
EXEC
Command History
Usage Guidelines
If you omit all optional arguments and keywords, the show ip mroute command displays all entries in the IP multicast routing table.
The Cisco IOS software populates the multicast routing table by creating source, group (S,G) entries from star, group (*,G) entries. The star refers to all source addresses, the "S" refers to a single source address, and the "G" is the destination multicast group address. In creating (S,G) entries, the software uses the best path to that destination group found in the unicast routing table (that is, through Reverse Path Forwarding [RPF]).
Examples
The following is sample output from the show ip mroute command for a router operating in dense mode. This command displays the contents of the IP multicast routing table for the multicast group named cbone-audio.
Router# show ip mroute cbone-audioIP Multicast Routing TableFlags: D - Dense, S - Sparse, C - Connected, L - Local, P - PrunedR - RP-bit set, F - Register flag, T - SPT-bit setTimers: Uptime/ExpiresInterface state: Interface, Next-Hop, State/Mode(*, 224.0.255.1), uptime 0:57:31, expires 0:02:59, RP is 0.0.0.0, flags: DCIncoming interface: Null, RPF neighbor 0.0.0.0, DvmrpOutgoing interface list:Ethernet0, Forward/Dense, 0:57:31/0:02:52Tunnel0, Forward/Dense, 0:56:55/0:01:28(198.92.37.100/32, 224.0.255.1), uptime 20:20:00, expires 0:02:55, flags: CIncoming interface: Tunnel0, RPF neighbor 10.20.37.33, DvmrpOutgoing interface list:Ethernet0, Forward/Dense, 20:20:00/0:02:52The following is sample output from the show ip mroute command for a router operating in sparse mode:
Router# show ip mrouteIP Multicast Routing TableFlags: D - Dense, S - Sparse, C - Connected, L - Local, P - PrunedR - RP-bit set, F - Register flag, T - SPT-bit setTimers: Uptime/ExpiresInterface state: Interface, Next-Hop, State/Mode(*, 224.0.255.3), uptime 5:29:15, RP is 198.92.37.2, flags: SCIncoming interface: Tunnel0, RPF neighbor 10.3.35.1, DvmrpOutgoing interface list:Ethernet0, Forward/Sparse, 5:29:15/0:02:57(198.92.46.0/24, 224.0.255.3), uptime 5:29:15, expires 0:02:59, flags: CIncoming interface: Tunnel0, RPF neighbor 10.3.35.1Outgoing interface list:Ethernet0, Forward/Sparse, 5:29:15/0:02:57The following is sample output from the show ip mroute command that shows the VCD value, because an ATM interface with PIM multipoint signalling is enabled:
Router# show ip mroute 224.1.1.1IP Multicast Routing TableFlags: D - Dense, S - Sparse, C - Connected, L - Local, P - PrunedR - RP-bit set, F - Register flag, T - SPT-bit set, J - Join SPTTimers: Uptime/ExpiresInterface state: Interface, Next-Hop or VCD, State/Mode(*, 224.1.1.1), 00:03:57/00:02:54, RP 130.4.101.1, flags: SJIncoming interface: Null, RPF nbr 0.0.0.0Outgoing interface list:ATM0/0, VCD 14, Forward/Sparse, 00:03:57/00:02:53The following is sample output from the show ip mroute command with the summary keyword:
Router# show ip mroute summaryIP Multicast Routing TableFlags: D - Dense, S - Sparse, C - Connected, L - Local, P - PrunedR - RP-bit set, F - Register flag, T - SPT-bit set, J - Join SPTTimers: Uptime/ExpiresInterface state: Interface, Next-Hop, State/Mode(*, 224.255.255.255), 2d16h/00:02:30, RP 171.69.10.13, flags: SJPC(*, 224.2.127.253), 00:58:18/00:02:00, RP 171.69.10.13, flags: SJC(*, 224.1.127.255), 00:58:21/00:02:03, RP 171.69.10.13, flags: SJC(*, 224.2.127.254), 2d16h/00:00:00, RP 171.69.10.13, flags: SJCL(128.9.160.67/32, 224.2.127.254), 00:02:46/00:00:12, flags: CLJT(129.48.244.217/32, 224.2.127.254), 00:02:15/00:00:40, flags: CLJT(130.207.8.33/32, 224.2.127.254), 00:00:25/00:02:32, flags: CLJT(131.243.2.62/32, 224.2.127.254), 00:00:51/00:02:03, flags: CLJT(140.173.8.3/32, 224.2.127.254), 00:00:26/00:02:33, flags: CLJT(171.69.60.189/32, 224.2.127.254), 00:03:47/00:00:46, flags: CLJTThe following is sample output from the show ip mroute command with the active keyword:
Router# show ip mroute activeActive IP Multicast Sources - sending >= 4 kbpsGroup: 224.2.127.254, (sdr.cisco.com)Source: 146.137.28.69 (mbone.ipd.anl.gov)Rate: 1 pps/4 kbps(1sec), 4 kbps(last 1 secs), 4 kbps(life avg)Group: 224.2.201.241, ACM 97Source: 130.129.52.160 (webcast3-e1.acm97.interop.net)Rate: 9 pps/93 kbps(1sec), 145 kbps(last 20 secs), 85 kbps(life avg)Group: 224.2.207.215, ACM 97Source: 130.129.52.160 (webcast3-e1.acm97.interop.net)Rate: 3 pps/31 kbps(1sec), 63 kbps(last 19 secs), 65 kbps(life avg)The following is sample output from the show ip mroute command with the count keyword:
Router# show ip mroute countIP Multicast Statistics - Group count: 8, Average sources per group: 9.87Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kilobits per secondGroup: 224.255.255.255, Source count: 0, Group pkt count: 0RP-tree: 0/0/0/0Group: 224.2.127.253, Source count: 0, Group pkt count: 0RP-tree: 0/0/0/0Group: 224.1.127.255, Source count: 0, Group pkt count: 0RP-tree: 0/0/0/0Group: 224.2.127.254, Source count: 9, Group pkt count: 14RP-tree: 0/0/0/0Source: 128.2.6.9/32, 2/0/796/0Source: 128.32.131.87/32, 1/0/616/0Source: 128.125.51.58/32, 1/0/412/0Source: 130.207.8.33/32, 1/0/936/0Source: 131.243.2.62/32, 1/0/750/0Source: 140.173.8.3/32, 1/0/660/0Source: 146.137.28.69/32, 1/0/584/0Source: 171.69.60.189/32, 4/0/447/0Source: 204.162.119.8/32, 2/0/834/0Group: 224.0.1.40, Source count: 1, Group pkt count: 3606RP-tree: 0/0/0/0Source: 171.69.214.50/32, 3606/0/48/0, RPF Failed: 1203Group: 224.2.201.241, Source count: 36, Group pkt count: 54152RP-tree: 7/0/108/0Source: 13.242.36.83/32, 99/0/123/0Source: 36.29.1.3/32, 71/0/110/0Source: 128.9.160.96/32, 505/1/106/0Source: 128.32.163.170/32, 661/1/88/0Source: 128.115.31.26/32, 192/0/118/0Source: 128.146.111.45/32, 500/0/87/0Source: 128.183.33.134/32, 248/0/119/0Source: 128.195.7.62/32, 527/0/118/0Source: 128.223.32.25/32, 554/0/105/0Source: 128.223.32.151/32, 551/1/125/0Source: 128.223.156.117/32, 535/1/114/0Source: 128.223.225.21/32, 582/0/114/0Source: 129.89.142.50/32, 78/0/127/0Source: 129.99.50.14/32, 526/0/118/0Source: 130.129.0.13/32, 522/0/95/0Source: 130.129.52.160/32, 40839/16/920/161Source: 130.129.52.161/32, 476/0/97/0Source: 130.221.224.10/32, 456/0/113/0Source: 132.146.32.108/32, 9/1/112/0The following example of show ip mroute is displayed when IP multicast MLS is configured. Note that the "H" indicates hardware switched.
Router# show ip mrouteIP Multicast Routing TableFlags: D - Dense, S - Sparse, C - Connected, L - Local, P - PrunedR - RP-bit set, F - Register flag, T - SPT-bit set, J - Join SPT, H - Hardware switchedTimers: Uptime/Expires(*, 229.10.0.1), 00:04:35/00:02:59, RP 0.0.0.0, flags: DJCIncoming interface: Null, RPF nbr 0.0.0.0Outgoing interface list:Vlan6, Forward/Dense, 00:00:30/00:02:30Vlan5, Forward/Dense, 00:04:35/00:02:30Vlan2, Forward/Dense, 00:01:28/00:00:00(192.0.2.20, 229.10.0.1), 00:04:35/00:02:27, flags: CTIncoming interface: Vlan2, RPF nbr 0.0.0.0Outgoing interface list:Vlan5, Forward/Dense, 00:03:25/00:00:00, HVlan6, Forward/Dense, 00:00:10/00:00:00, Hdescribes the fields shown in the displays.
Related Commands
ip multicast routing
Enables IP multicast routing.
ip pim
Enables PIM and IGMP on an interface.
show ip pim interface
To display information about interfaces configured for Protocol Independent Multicast (PIM), use the show ip pim interface EXEC command.
show ip pim interface [type number] [count]
Syntax Description
type
(Optional) Interface type.
number
(Optional) Interface number.
count
(Optional) Number of packets received and sent out the interface.
Command Modes
EXEC
Command History
Usage Guidelines
This command works only on interfaces that are configured for PIM.
Examples
The following is sample output from the show ip pim interface command:
Router# show ip pim interfaceAddress Interface Mode Neighbor Query DRCount Interval198.92.37.6 Ethernet0 Dense 2 30 198.92.37.33198.92.36.129 Ethernet1 Dense 2 30 198.92.36.13110.1.37.2 Tunnel0 Dense 1 30 0.0.0.0The following is sample output from the show ip pim interface command with a count:
Router# show ip pim interface countAddress Interface FS Mpackets In/Out171.69.121.35 Ethernet0 * 548305239/13744856171.69.121.35 Serial0.33 * 8256/67052912198.92.12.73 Serial0.1719 * 219444/862191The following is sample output from the show ip pim interface command with a count when IP multicast MLS is enabled. The examples lists the PIM interfaces that are fast switched and process switched, and the packet counts for these. The "H" is added to interfaces where IP multicast MLS is enabled.
Router# show ip pim interface countStates: FS - Fast Switched, H - Hardware SwitchedAddress Interface FS Mpackets In/Out192.1.10.2 Vlan10 * H 40886/0192.1.11.2 Vlan11 * H 0/40554192.1.12.2 Vlan12 * H 0/40554192.1.23.2 Vlan23 * 0/0192.1.24.2 Vlan24 * 0/0describes the fields shown in the displays.
Related Commands
ip pim
Enables PIM on an interface.
show ip pim neighbor
Lists the PIM neighbors discovered by the Cisco IOS software.
show mls rp ip multicast
To display hardware-switched multicast flow information about IP multicast Multilayer Switching (MLS), use the show mls rp ip multicast EXEC command.
show mls rp ip multicast [locate] [group [source] [vlan-id ]] | [statistics] | [summary]
Syntax Description
Command Modes
EXEC
Command History
Examples
The following is sample output of the show mls rp ip multicast command using the locate keyword:
Router# show mls rp ip multicast locateSource Group Vlan SwitchIP SwitchMAC------ ----- ---- -------- ---------192.1.10.6 239.255.158.197 10 1.2.10.199 0010.a60b.b4ffThe following is sample output of the show mls rp ip multicast command for a specific IP multicast group:
Router# show mls rp ip multicast 224.1.1.1Multicast hardware switched flows:(1.1.13.1, 224.1.1.1) Incoming interface: Vlan13, Packets switched: 61590Hardware switched outgoing interfaces: Vlan20 Vlan9MFD installed: Vlan13(1.1.9.3, 224.1.1.1) Incoming interface: Vlan9, Packets switched: 0Hardware switched outgoing interfaces: Vlan20MFD installed: Vlan9(1.1.12.1, 224.1.1.1) Incoming interface: Vlan12, Packets switched: 62010Hardware switched outgoing interfaces: Vlan20 Vlan9MFD installed: Vlan12(1.1.12.3, 224.1.1.1) Incoming interface: Vlan12, Packets switched: 61980Hardware switched outgoing interfaces: Vlan20 Vlan9MFD installed: Vlan12(1.1.11.1, 224.1.1.1) Incoming interface: Vlan11, Packets switched: 62430Hardware switched outgoing interfaces: Vlan20 Vlan9MFD installed: Vlan11(1.1.11.3, 224.1.1.1) Incoming interface: Vlan11, Packets switched: 62430Hardware switched outgoing interfaces: Vlan20 Vlan9MFD installed: Vlan11Total shortcut installed: 6The following is sample output of the show mls rp ip multicast command using the statistics keyword:
Router# show mls rp ip multicast statisticsMLS Multicast Operation Status:MLS Multicast configuration and state:Router Mac: 0010.298f.0009Switch Mac: 0010.0d70.a3ff Switch IP: 1.2.10.195MLS Multicast Operating state: ACTIVEActive management vlan: Vlan1, 192.1.4.1User configured management vlan: None, 0.0.0.0Include-List: IP1 = 192.1.28.2, IP2 = 0.0.0.0Router IP used in MLS Multicast messages: 192.1.28.2MLS Multicast statistics:Keepalive sent: 90Keepalive ACK received: 90Open request sent: 3Open request ACK received: 3Delete notifications received: 3Flow statistics messages received: 181Flow message sent: 14Flow message Ack received: 14Flow message Nack received: 0Flow install Ack: 2Flow install Nack: 0Flow update Ack: 7Flow update Nack: 0Flow delete Ack: 0Complete flow install Ack: 3Complete flow install Nack: 0Complete flow delete Ack: 1Input vlan delete Ack: 0Output vlan delete Ack: 0Global delete sent: 1L2 entry not found error: 0LTL entry not found error: 0MET entry not found error: 0L3 entry not found error: 0L3 entry exists error : 0Hash collision error : 0Sequence number error : 0None-supported error : 0Generic error : 0The following is sample output of the show mls rp ip multicast command using the summary keyword:
Router# show mls rp ip multicast summarySwitch IP:0.0.0.0 Switch MAC:0000.0000.0000Number of complete flows: 0Total hardware-switched flows: 0Switch IP:1.2.10.199 Switch MAC:0010.a60b.b4ffNumber of complete flows: 1Total hardware-switched flows: 1Related Commands
Debug Commands
This section documents new debug commands. All other commands used with this feature are documented in this feature module or the Cisco IOS Release 12.0 command reference publications.
debug mdss
To display the run-time errors and sequence of events for the multicast distributed switching services (MDSS), use the debug mdss privileged EXEC command. Use the no form of the command to disable debugging output.
[no] debug mdss {all | error | event}
Syntax Description
all
Displays both errors and sequence of events for MDSS.
error
Displays the run-time errors for MDSS.
event
Displays the run-time sequence of events for MDSS.
Defaults
Debugging is not enabled.
Command History
Examples
The following example shows output using the debug mdss command:
Router# debug mdss allmdss all debugging is onRouter# clear ip mroute *Router#01:31:03: MDSS: got MDFS_CLEARALL01:31:03: MDSS: --> mdss_flush_all_sc01:31:03: MDSS: enqueue a FE_GLOBAL_DELETE01:31:03: MDSS: got MDFS_MROUTE_ADD for (0.0.0.0, 224.0.1.40)01:31:03: MDSS: --> mdss_free_scmdb_cache01:31:03: MDSS: got MDFS_MROUTE_ADD for (0.0.0.0, 239.255.158.197)01:31:03: MDSS: got MDFS_MROUTE_ADD for (192.1.21.6, 239.255.158.197)01:31:03: MDSS: got a MDFS_MIDB_ADD for (192.1.21.6, 239.255.158.197,Vlan21) +Vlan2201:31:03: MDSS: -- mdss_add_oif01:31:03: MDSS: enqueue a FE_OIF_ADD (192.1.21.6, 239.255.158.197,Vlan21) +Vlan2201:31:03: MDSS: mdb (192.1.21.6, 239.255.158.197) fast_flags |MCACHE_MTU01:31:03: MDSS: got a MDFS_MIDB_ADD for (192.1.21.6, 239.255.158.197,Vlan21) +Vlan2301:31:03: MDSS: -- mdss_add_oif01:31:03: MDSS: enqueue a FE_OIF_ADD (192.1.21.6, 239.255.158.197,Vlan21) +Vlan2301:31:03: MDSS: mdb (192.1.21.6, 239.255.158.197) fast_flags |MCACHE_MTU01:31:03: MDSS: got a MDFS_MIDB_ADD for (192.1.21.6, 239.255.158.197,Vlan21) +Vlan2401:31:03: MDSS: -- mdss_add_oif01:31:03: MDSS: enqueue a FE_OIF_ADD (192.1.21.6, 239.255.158.197,Vlan21) +Vlan2401:31:03: MDSS: mdb (192.1.21.6, 239.255.158.197) fast_flags |MCACHE_MTU01:31:03: MDSS: got a MDFS_MIDB_ADD for (192.1.21.6, 239.255.158.197,Vlan21) +Vlan2501:31:03: MDSS: -- mdss_add_oif01:31:03: MDSS: enqueue a FE_OIF_ADD (192.1.21.6, 239.255.158.197,Vlan21) +Vlan2501:31:03: MDSS: mdb (192.1.21.6, 239.255.158.197) fast_flags |MCACHE_MTU01:31:03: MDSS: got a MDFS_MIDB_ADD for (192.1.21.6, 239.255.158.197,Vlan21) +Vlan2601:31:03: MDSS: -- mdss_add_oif01:31:03: MDSS: enqueue a FE_OIF_ADD (192.1.21.6, 239.255.158.197,Vlan21) +Vlan2601:31:03: MDSS: mdb (192.1.21.6, 239.255.158.197) fast_flags |MCACHE_MTU01:31:03: MDSS: got a MDFS_MIDB_ADD for (192.1.21.6, 239.255.158.197,uVlan21) +Vlan27Related Commands
debug mls rp ip multicast
To display information about Multilayer Switching Protocol (MLSP), use the debug mls rp ip multicast privileged EXEC command. Use the no form of the command to disable debugging output.
[no] debug mls rp ip multicast {all | error | event | packet}
Syntax Description
Defaults
Debugging is not enabled.
Command History
Usage Guidelines
One and only one of the keywords is required.
Examples
The following example shows output from the debug mls rp ip multicast command using the error keyword:
Router# debug mls rp ip multicast errormlsm error debugging is onchtang-7200#06:06:45: MLSMERR: scb is INACTIVE, free INSTALL_FE06:06:46: MLSM: --> mlsm_proc_sc_ins_req(10.0.0.1, 224.2.2.3, 10)The following example shows output from the debug mls rp ip multicast command using the event keyword:
Router# debug mls rp ip multicast eventmlsm events debugging is onRouter#3d23h: MSCP: incoming shortcut flow statistic from Fa2/0.113d23h: MLSM: Flow_stat: (192.1.10.6, 239.255.158.197), byte :537792packet:84033d23h: MLSM: byte delta:7680 packet delta:120, time delta: 103d23h: MSCP: incoming shortcut flow statistic from Fa2/0.113d23h: MLSM: Flow_stat: (192.1.10.6, 239.255.158.197), byte :545472packet:85233d23h: MLSM: byte delta:7680 packet delta:120, time delta: 103d23h: MSCP: Router transmits keepalive_msg on Fa2/0.113d23h: MSCP: incoming shortcut keepalive ACK from Fa2/0.113d23h: MLSM: Include-list: (192.1.2.1 -> 0.0.0.0)3d23h: MSCP: incoming shortcut flow statistic from Fa2/0.113d23h: MLSM: Flow_stat: (192.1.10.6, 239.255.158.197), byte :553152packet:8643The following example shows output from the debug mls rp ip multicast command using the packet keyword:
Router# debug mls rp ip multicast packetmlsm packets debugging is onRouter#Router#Router#Router#**23h: MSCP(I): 01 00 0c cc cc cc 00 e0 1e 7c fe 5f 00 30 aa aa...LLL.`.|~_.0..23h: MSCP(I): 03 00 00 0c 01 07 01 05 00 28 01 02 0a c7 00 10.........(...G..23h: MSCP(I): a6 0b b4 ff 00 00 c0 01 0a 06 ef ff 9e c5 00 00&.4...@...o..E3d23h: MSCP(I): 00 00 00 09 42 c0 00 00 00 00 00 00 25 0b....B@......%.3d23h:**23h: MSCP(O): 01 00 0c 00 00 00 aa 00 04 00 01 04 00 00 aa aa......*.......LL23h: MSCP(O): 03 00 00 0c 00 16 00 00 00 00 01 00 0c cc cc cc.............L..23h: MSCP(O): aa 00 04 00 01 04 00 24 aa aa 03 00 00 0c 01 07*......$**......23h: MSCP(O): 01 06 00 1c c0 01 02 01 aa 00 04 00 01 04 00 00....@...*.....3d23h: MSCP(O): 00 0b 00 00 00 00 00 00 01 01 0a 62 ...........b3d23h:**23h: MSCP(I): 01 00 0c cc cc cc 00 e0 1e 7c fe 5f 00 24 aa aa...LLL.`.|~_.$..23h: MSCP(I): 03 00 00 0c 01 07 01 86 00 1c 01 02 0a c7 00 10.............G..23h: MSCP(I): a6 0b b4 ff 00 00 00 0b 00 00 c0 01 02 01 00 00..4.......@...3d23h: MSCP(I): 00 003d23h:Related Commands
