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This chapter describes how to configure IP multicast Multilayer Switching (multicast MLS).
This chapter consists of these sections:
These sections provide an overview of IP multicast MLS and describe how multicast MLS works:
IP multicast MLS provides high-performance hardware-based Layer 3 switching of IP multicast traffic for Catalyst 5000 series LAN switches. Multicast MLS switches IP multicast data packet flows between IP subnets using advanced application-specific integrated circuit (ASIC) switching hardware, offloading processor-intensive multicast packet routing from network routers.
The packet forwarding function is moved onto Layer 3 switches 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.
An IP multicast MLS network topology consists of these components (for more information about hardware and software requirements, see the "Software and Hardware Requirements" section):
An IP multicast flow is a unidirectional sequence of packets between a particular multicast source and the members of a destination multicast group. Flows are based on the IP address of the source device, the destination IP multicast group address, and the source VLAN.
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 multicast forwarding table entries are populated by whichever multicast service is enabled on the switch (CGMP, IGMP snooping, or GMRP). These entries map the destination multicast MAC address to outgoing switch ports for a given VLAN.
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, cache entries exceeding 32K increases the 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 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.
These router commands affect the Layer 3 MLS cache entries on the switch:
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.
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, if there are members of group G1 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 as follows:
| Frame Header | IP Header | Payload | |||||
|---|---|---|---|---|---|---|---|
Destination | Source | Destination | Source | TTL | Checksum | Data | Checksum |
Group G1 MAC | Server A MAC | Group G1 IP | Server A IP | n | calculation1 | ||
The MMLS-SE rewrites the packet as follows:
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:
| Frame Header | IP Header | Payload | |||||
|---|---|---|---|---|---|---|---|
Destination | Source | Destination | Source | TTL | Checksum | Data | Checksum |
Group G1 MAC | MMLS-RP MAC | Group G1 IP | Server A IP | n-1 | calculation2 | ||
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:
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 requires specific network topologies to function correctly. The basic topology consists of a switch and a single internal or external router connected through an ISL or 802.1Q trunk link. Figure 45-1 shows this basic configuration before and after IP multicast MLS is deployed (assuming a completely switched flow).
IP multicast MLS requires these software and hardware versions:
Table 45-1 shows the default IP multicast MLS switch configuration. Table 45-2 shows the default IP multicast MLS router configuration.
| Feature | Default Value |
|---|---|
Multicast services (CGMP, IGMP snooping, or GMRP) | Disabled |
IP multicast MLS | Disabled |
Participating routers | None specified |
| Feature | Default Value |
|---|---|
Multicast routing | Disabled globally |
PIM routing | Disabled on all interfaces |
IP multicast MLS | Enabled when PIM is enabled on the interface |
IP multicast MLS management interface | Whichever subinterface (or VLAN interface) has the lowest VLAN ID and is active (in the "up" state) |
These sections describe configuration guidelines that apply when configuring IP multicast MLS:
These guidelines and restrictions apply when configuring the switch for IP multicast MLS:
IP multicast MLS does not perform multilayer switching for an IP multicast flow in the following situations:
Follow these guidelines when using an external router:
These restrictions apply when using access lists on interfaces participating in IP multicast MLS:
Router(config)#access-list 101 permit udp any any Router(config)#access-list 101 permit ip any any
Router(config)#access-list 101 permit udp s1 g1 Router(config)#access-list 101 permit ip any any
If IP multicast MLS is enabled, IP accounting for the interface will not reflect accurate values.
These sections describe how to configure a router for IP multicast MLS.
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 globally on the router, perform this task in global configuration mode:
| Task | Command |
|---|---|
Enable IP multicast routing globally. | Router(config)#ip multicast-routing |
This example shows how to enable multicast routing globally:
Router(config)#ip multicast-routing Router(config)#
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 enable IP PIM on an interface, perform this task in interface configuration mode:
| Task | Command |
|---|---|
Enable IP PIM on a router interface. | Router(config-if)#ip pim {dense-mode | sparse-mode | sparse-dense-mode} |
This example shows how to enable PIM on an interface using the default mode (sparse-dense-mode):
Router(config-if)#ip pim Router(config-if)#
This example shows how to enable PIM sparse-mode on an interface:
Router(config-if)#ip pim sparse-mode Router(config-if)#
IP multicast MLS is enabled by default on the router interface when you enable PIM on the interface. Perform this task only if you disabled IP multicast MLS on the interface and you want to reenable it.
To enable IP multicast MLS on a router interface, perform this task in interface configuration mode:
| Task | Command |
|---|---|
Enable IP multicast MLS on a router interface. | Router(config-if)#mls rp ip multicast |
This example shows how to enable IP multicast MLS on a router interface:
Router(config-if)#mls rp ip multicast Router(config-if)#
Optionally, you can specify a different router interface or subinterface as the management interface. We recommend using a subinterface with minimal data traffic for the management interface so that multicast MLSP packets can be transmitted and received more quickly. In most cases, the VLAN 1 interface should be used. If the user-configured management interface goes down, the router uses the default interface until the user-configured interface comes up again.
To change the default IP multicast MLS management interface, perform this task in interface configuration mode:
| Task | Command |
|---|---|
Configure a router subinterface as the IP multicast MLS management interface. | Router(config-if)#mls rp ip multicast management-interface |
This example shows how to configure a router subinterface as the IP multicast MLS management interface:
Router(config-if)#mls rp ip multicast management-interface Router(config-if)#
To remove a router interface as an IP multicast MLS management interface, perform this task in interface configuration mode:
| Task | Command |
|---|---|
Remove a router interface as an IP multicast MLS management interface. | Router(config-if)#no mls rp ip multicast management-interface |
This example shows how to remove a router interface as an IP multicast MLS management interface:
Router(config-if)#no mls rp ip multicast management-interface Router(config-if)#
To disable IP multicast MLS on a router interface, perform this task in interface configuration mode:
| Task | Command |
|---|---|
Disable IP multicast MLS on a router interface. | Router(config-if)#no mls rp ip multicast |
This example shows how to disable IP multicast MLS on a router interface:
Router(config-if)#no mls rp ip multicast Router(config-if)#
The show ip pim interface count command displays the IP multicast MLS enable state on MMLS-RP IP PIM interfaces and and the number of packets received and sent on the interface.
To display IP multicast MLS information for an IP PIM router interface, perform this task:
| Task | Command |
|---|---|
Display IP multicast MLS information for an MMLS-RP IP PIM router interface. | show ip pim interface [type number] count |
This example shows how to display IP multicast MLS information for all MMLS-RP IP PIM router interfaces (the "H" flag indicates that IP multicast MLS is enabled on the interface):
Router#show ip pim interface count
State: * - Fast Switched, D - Distributed Fast Switched
H - Hardware Switched
Address Interface FS Mpackets In/Out
192.1.0.1 FastEthernet2/0 * 0/0
192.1.10.1 FastEthernet2/0.10 * H 2105244/0
192.1.11.1 FastEthernet2/0.11 * H 0/0
192.1.12.1 FastEthernet2/0.12 * H 0/2105244
192.1.13.1 FastEthernet2/0.13 * H 0/2105244
192.1.14.1 FastEthernet2/0.14 * H 0/2105244
192.1.15.8 FastEthernet2/0.15 * H 0/2105244
192.1.16.8 FastEthernet2/0.16 * H 0/2105244
192.1.17.8 FastEthernet2/0.17 * H 0/2105244
192.1.18.8 FastEthernet2/0.18 * H 0/2105244
Router#
This example shows how to display IP multicast MLS information for a specific MMLS-RP IP PIM router interface:
Router#show ip pim interface fastethernet2/0.12 count
State: * - Fast Switched, D - Distributed Fast Switched
H - Hardware Switched
Address Interface FS Mpackets In/Out
192.1.12.1 FastEthernet2/0.12 * H 0/2105004
Router#
The show ip mroute command displays the IP multicast routing table on the router.
To display the IP multicast routing table, perform this task:
| Task | Command |
|---|---|
Display the IP multicast routing table. | show ip mroute [group[source]] | [summary] | [count] | [active kbps] |
This example shows how to display the IP multicast routing table (the "H" flag indicates that the multicast flow is being multilayer switched):
Router#show ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, C - Connected, L - Local, P - Pruned
R - RP-bit set, F - Register flag, T - SPT-bit set, J - Join SPT
Outgoing Interface Flags: H - Hardware switched
Timers: Uptime/Expires
Interface state: Interface, Next-Hop or VCD, State/Mode
(*, 239.255.158.197), 2w0d/00:02:59, RP 0.0.0.0, flags: DJC
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
FastEthernet2/0.19, Forward/Sparse, 1w2d/00:02:52
FastEthernet2/0.18, Forward/Sparse, 1w2d/00:02:51
FastEthernet2/0.17, Forward/Sparse, 1w2d/00:02:50
FastEthernet2/0.16, Forward/Sparse, 1w2d/00:02:49
FastEthernet2/0.15, Forward/Sparse, 1w2d/00:02:46
FastEthernet2/0.14, Forward/Sparse, 1w2d/00:02:46
FastEthernet2/0.13, Forward/Sparse, 1w2d/00:02:45
FastEthernet2/0.12, Forward/Sparse, 1w2d/00:02:45
FastEthernet2/0.10, Forward/Sparse, 1w2d/00:02:43
(192.1.10.6, 239.255.158.197), 1w2d/00:02:59, flags: CT
Incoming interface: FastEthernet2/0.10, RPF nbr 0.0.0.0
Outgoing interface list:
FastEthernet2/0.19, Forward/Sparse, 1w2d/00:02:51, H
FastEthernet2/0.18, Forward/Sparse, 1w2d/00:02:50, H
FastEthernet2/0.17, Forward/Sparse, 1w2d/00:02:49, H
FastEthernet2/0.16, Forward/Sparse, 1w2d/00:02:48, H
FastEthernet2/0.15, Forward/Sparse, 1w2d/00:02:46, H
FastEthernet2/0.14, Forward/Sparse, 1w2d/00:02:45, H
FastEthernet2/0.13, Forward/Sparse, 1w2d/00:02:44, H
FastEthernet2/0.12, Forward/Sparse, 1w2d/00:02:44, H
(*, 224.0.1.40), 2w0d/00:00:00, RP 0.0.0.0, flags: DJCL
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
FastEthernet2/0, Forward/Dense, 2w0d/00:00:00
<...output truncated...>
Router#
This example shows how to display summary information about the IP multicast MLS routing table:
Router#show ip mroute summary
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, C - Connected, L - Local, P - Pruned
R - RP-bit set, F - Register flag, T - SPT-bit set, J - Join SPT
Outgoing Interface Flags: H - Hardware switched
Timers: Uptime/Expires
Interface state: Interface, Next-Hop or VCD, State/Mode
(*, 224.0.1.40), 01:19:02/00:00:00, RP 0.0.0.0, flags: DJCL
(*, 224.0.1.1), 00:00:23/00:02:36, RP 0.0.0.0, flags: DJC
(*, 224.1.1.1), 01:19:02/00:02:59, RP 0.0.0.0, flags: DJ
(1.1.9.3, 224.1.1.1), 00:00:46/00:02:59, flags: T
(1.1.11.1, 224.1.1.1), 00:00:46/00:02:55, flags: T
(1.1.11.3, 224.1.1.1), 00:00:46/00:02:55, flags: T
(1.1.12.1, 224.1.1.1), 00:00:46/00:02:55, flags: T
(1.1.12.3, 224.1.1.1), 00:00:46/00:02:55, flags: T
(1.1.13.1, 224.1.1.1), 00:00:46/00:02:55, flags: T
(*, 224.1.1.2), 00:33:26/00:02:59, RP 0.0.0.0, flags: DJ
(1.1.9.3, 224.1.1.2), 00:00:46/00:02:59, flags: T
(*, 224.1.1.3), 00:33:26/00:02:59, RP 0.0.0.0, flags: DJ
(1.1.9.3, 224.1.1.3), 00:00:46/00:02:59, flags: T
<...output truncated...>
Router#
The show mls rp ip multicast command displays detailed information about IP multicast MLS.
To display detailed multicast MLS information on the router, perform this task:
| Task | Command |
|---|---|
| show mls rp ip multicast [[group[source][vlan-id]] | [*]] |
| show mls rp ip multicast summary |
| show mls rp ip multicast statistics |
This example shows how to display information on a specific IP multicast MLS entry on the router:
Router#show mls rp ip multicast 224.1.1.1 Multicast hardware switched flows: (1.1.13.1, 224.1.1.1) Incoming interface: Vlan13, Packets switched: 61590 Hardware switched outgoing interfaces: Vlan20 Vlan9 MFD installed: Vlan13 (1.1.9.3, 224.1.1.1) Incoming interface: Vlan9, Packets switched: 0 Hardware switched outgoing interfaces: Vlan20 MFD installed: Vlan9 (1.1.12.1, 224.1.1.1) Incoming interface: Vlan12, Packets switched: 62010 Hardware switched outgoing interfaces: Vlan20 Vlan9 MFD installed: Vlan12 (1.1.12.3, 224.1.1.1) Incoming interface: Vlan12, Packets switched: 61980 Hardware switched outgoing interfaces: Vlan20 Vlan9 MFD installed: Vlan12 (1.1.11.1, 224.1.1.1) Incoming interface: Vlan11, Packets switched: 62430 Hardware switched outgoing interfaces: Vlan20 Vlan9 MFD installed: Vlan11 (1.1.11.3, 224.1.1.1) Incoming interface: Vlan11, Packets switched: 62430 Hardware switched outgoing interfaces: Vlan20 Vlan9 MFD installed: Vlan11 Total shortcut installed: 6 Router#
This example shows how to display a summary of IP multicast MLS information on the router:
Router#show mls rp ip multicast summary Switch IP:172.20.49.152 Switch MAC:0010.1f2e.39ff Number of complete flows: 35 Total hardware-switched flows: 35 Router#
This example shows how to display IP multicast MLS statistics on the router:
Router# show mls rp ip multicast statistics
MLS Multicast Operation Status:
MLS Multicast configuration and state:
Router Mac: 0050.0f06.3ca0
Switch Mac: 0010.1f2e.39ff Switch IP: 172.20.49.152
MLS Multicast Operating state: ACTIVE
Active management vlan: FastEthernet0.1, 172.20.49.169
User configured management vlan: None, 0.0.0.0
Include-List: IP1 = 1.1.9.254, IP2 = 1.1.5.252
Router IP used in MLS Multicast messages: 1.1.9.254
MLS Multicast statistic:
Keepalive sent: 317
Keepalive ACK sent: 317
Open request sent: 4
Open request ACK received: 4
Delete notifications received: 21
Flow statistics messages received: 3
NACK received: 382
Flow install sent: 13
Selective delete sent: 0
Complete flow install sent: 13
Complete flow delete sent: 0
Input VLAN delete sent: 0
Output VLAN delete sent: 0
Global delete sent: 0
Router#
The show mls rp ip multicast locate command displays information about which switch is multilayer switching a given IP multicast MLS flow.
To identify which switch is multilayer switching a flow, perform this task:
| Task | Command |
|---|---|
Identify which switch is multilayer switching an IP multicast MLS flow. | show mls rp ip multicast locate [group[source]] [vlan-id]] | [*] |
This example shows how to identify which switch is multilayer switching an IP multicast MLS flow:
Router#show mls rp ip multicast locate 224.1.1.1 Source Group Vlan SwitchIP SwitchMAC ------ ----- ---- -------- --------- 1.1.13.1 224.1.1.1 13 172.20.49.152 0010.1f2e.39ff 1.1.9.3 224.1.1.1 9 172.20.49.152 0010.1f2e.39ff 1.1.12.1 224.1.1.1 12 172.20.49.152 0010.1f2e.39ff 1.1.12.3 224.1.1.1 12 172.20.49.152 0010.1f2e.39ff 1.1.11.1 224.1.1.1 11 172.20.49.152 0010.1f2e.39ff 1.1.11.3 224.1.1.1 11 172.20.49.152 0010.1f2e.39ff Router#
Table 45-3 describes IP multicast MLS-related debug commands that you can use to troubleshoot multicast MLS problems on the router.
| Command | Description |
|---|---|
[no] debug mls rp ip multicast event | Displays the run-time sequence of events for multicast MLSP. |
[no] debug mls rp ip multicast packet | Displays the packet contents of multicast MLSP packets. |
[no] debug mls rp ip multicast error | Displays error messages related to multicast MLSP packets. |
[no] debug mls rp ip multicast all | Enables display of all multicast MLSP debugging information. |
[no] debug mdss event | Displays the run-time sequence of events for MDSS1, which handles IP multicast route events (such as the addition or removal of routes from the routing table) and sends updates to the MMLS-SE using multicast MLSP. |
[no] debug mdss error | Displays error messages related to MDSS. |
[no] debug mdss all | Enables display of all MDSS debugging information. |
| 1MDSS=multicast distributed switching services |
These sections describe how to configure IP multicast MLS on the switch:
When you enable IP multicast MLS on the switch, the MMLS-RPs download flow information to the switch (MMLS-SE). The MMLS-SE stores the information in the Layer 3 MLS cache and begins multilayer switching IP multicast traffic. IP multicast MLS is disabled by default on the MMLS-SE.
To enable IP multicast MLS on the switch, perform this task in privileged mode:
| Task | Command |
|---|---|
Step 1 Enable IP multicast MLS on the switch. | set mls multicast enable |
Step 2 Verify that multicast MLS is enabled. | show mls multicast |
This example shows how to enable IP multicast MLS on the switch:
Console> (enable) set mls multicast enable Multilayer Switching for Multicast is enabled for this device. Console> (enable)
The MMLS-SE downloads and processes multicast flow information only from routers that have been included as MMLS-RPs.
To specify a router to participate in IP multicast MLS, perform this task in privileged mode:
| Task | Command |
|---|---|
Step 1 Specify the IP address of the MMLS-RP to participate in IP multicast MLS. | set mls multicast include [ip_addr] |
Step 2 Verify the configuration. | show mls multicast include |
This example shows how to specify an MMLS-RP interface to participate in IP multicast MLS:
Console> (enable) set mls multicast include 172.20.52.33 Multilayer switching for multicast is enabled for router 172.20.52.33 Console> (enable)
To remove a router from the list of routers participating in IP multicast MLS, perform this task in privileged mode:
| Task | Command |
|---|---|
Step 1 Remove an MMLS-RP from participation in IP multicast MLS. | clear mls multicast include [ip_addr] [all] |
Step 2 Verify the configuration. | show mls multicast include |
This example shows how to remove a router from the IP multicast MLS inclusion list on the switch:
Console> (enable) clear mls multicast include 172.20.52.33 MLS Router 172.20.52.33 is deleted from the include list. Console> (enable)
When you disable IP multicast MLS on the switch, the MMLS-SE stops multilayer switching IP multicast traffic, purges all IP multicast MLS information from the Layer 3 cache, and stops processing multicast MLSP messages sent from the MMLS-RPs.
To disable IP multicast MLS on the switch, perform this task in privileged mode:
| Task | Command |
|---|---|
Step 1 Disable IP multicast MLS on the switch. | set mls multicast disable |
Step 2 Verify that multicast MLS is disabled. | show mls multicast |
This example shows how to disable IP multicast MLS on the switch:
Console> (enable) set mls multicast disable Multilayer Switching for Multicast is disabled for this device. Console> (enable)
The show mls multicast command displays global IP multicast MLS configuration information and the state of participating MMLS-RPs.
To display global IP multicast MLS configuration information on the switch, perform this task:
| Task | Command |
|---|---|
Display global IP multicast MLS configuration information. | show mls multicast |
This example shows how to display global IP multicast MLS configuration information on the switch:
Console> (enable) show mls multicast
Admin Status: Enabled
Operational Status: Active
Configured flow mask is {Destination-source-vlan flow}
Active Entries = 10
Router include list :
1.1.9.254 (Active)
1.1.5.252 (Active)
Console> (enable)
The show mls multicast statistics rp command displays IP multicast MLS statistics for multicast MMLS-RPs.
To display IP multicast MMLS-RP statistics, perform this task:
| Task | Command |
|---|---|
Show IP multicast MMLS-RP statistics. | show mls multicast statistics rp [ip_addr] |
This example shows how to display IP multicast MMLS-RP statistics on the switch:
Console (enable) show mls multicast statistics rp
Router IP Router Name Router MAC
-------------------------------------------------------
1.1.9.254 ? 00-50-0f-06-3c-a0
Transmit:
Delete Notifications: 23
Acknowledgements: 92
Flow Statistics: 56
Receive:
Open Connection Requests: 1
Keep Alive Messages: 72
Shortcut Messages: 19
Shortcut Install TLV: 8
Selective Delete TLV: 4
Group Delete TLV: 0
Update TLV: 3
Input VLAN Delete TLV: 0
Output VLAN Delete TLV: 0
Global Delete TLV: 0
MFD Install TLV: 7
MFD Delete TLV: 0
Router IP Router Name Router MAC
-------------------------------------------------------
1.1.5.252 ? 00-10-29-8d-88-01
Transmit:
Delete Notifications: 22
Acknowledgements: 75
Flow Statistics: 22
Receive:
Open Connection Requests: 1
Keep Alive Messages: 68
Shortcut Messages: 6
Shortcut Install TLV: 4
Selective Delete TLV: 2
Group Delete TLV: 0
Update TLV: 0
Input VLAN Delete TLV: 0
Output VLAN Delete TLV: 0
Global Delete TLV: 0
MFD Install TLV: 4
MFD Delete TLV: 0
Console (enable)
The clear mls multicast statistics rp command clears IP multicast MLS statistics for all participating MMLS-RPs.
To clear IP multicast MLS statistics on the switch, perform this task in privileged mode:
| Task | Command |
|---|---|
Clear IP multicast MLS statistics on the switch. | clear mls multicast statistics rp |
This example shows how to clear IP multicast MLS statistics on the switch:
Console> (enable) clear mls multicast statistics rp All statistics for the MLS routers in include list are cleared. Console> (enable)
The show mls multicast entry command displays a variety of information about the multicast flows being handled by the MMLS-SE. You can display entries based on any combination of the participating MMLS-RP, the VLAN, the multicast group address, or the multicast traffic source.
To display information about IP multicast MLS entries on the switch, perform this task in privileged mode:
| Task | Command |
|---|---|
Display information about IP multicast MLS entries on the switch. | show mls multicast entry [[[rp ip_addr] [vlan vlan_id] [group ip_addr] [source ip_addr]] | [all]] [long] |
This example shows how to display all IP multicast MLS entries on the switch:
Console> (enable) show mls multicast entry all
Router IP Dest IP Source IP Pkts Bytes
InVlan OutVlans
--------------- --------------- --------------- ---------- --------------------
------ -------------------------------------------------------
1.1.5.252 224.1.1.1 1.1.11.1 15870 2761380
20
1.1.9.254 224.1.1.1 1.1.12.3 473220 82340280
12
1.1.5.252 224.1.1.1 1.1.12.3 15759 2742066
20
1.1.9.254 224.1.1.1 1.1.11.1 473670 82418580
11
1.1.5.252 224.1.1.1 1.1.11.3 15810 2750940
20
1.1.9.254 224.1.1.1 1.1.12.1 473220 82340280
12
1.1.5.252 224.1.1.1 1.1.13.1 15840 2756160
20
1.1.9.254 224.1.1.1 1.1.13.1 472770 82261980
13
1.1.5.252 224.1.1.1 1.1.12.1 15840 2756160
20
1.1.9.254 224.1.1.1 1.1.11.3 473667 82418058
11
Total Entries: 10
Console> (enable)
This example shows how to display IP multicast MLS entries for a specific MMLS-RP:
Console> (enable) show mls multicast entry rp 1.1.5.252
Router IP Dest IP Source IP Pkts Bytes
InVlan OutVlans
--------------- --------------- --------------- ---------- --------------------
------ -------------------------------------------------------
1.1.5.252 224.1.1.1 1.1.11.1 15870 2761380
20
1.1.5.252 224.1.1.1 1.1.12.3 15759 2742066
20
1.1.5.252 224.1.1.1 1.1.11.3 15810 2750940
20
1.1.5.252 224.1.1.1 1.1.13.1 15840 2756160
20
1.1.5.252 224.1.1.1 1.1.12.1 15840 2756160
20
Total Entries: 5
Console> (enable)
This example shows how to display IP multicast MLS entries for a specific multicast group address:
Console> (enable) show mls multicast entry group 224.1.1.1
Router IP Dest IP Source IP Pkts Bytes
InVlan OutVlans
--------------- --------------- --------------- ---------- --------------------
------ -------------------------------------------------------
1.1.5.252 224.1.1.1 1.1.11.1 15870 2761380
20
1.1.9.254 224.1.1.1 1.1.12.3 671400 116823600
12
1.1.5.252 224.1.1.1 1.1.12.3 15759 2742066
20
1.1.9.254 224.1.1.1 1.1.11.1 671853 116902422
11
1.1.9.254 224.1.1.1 1.1.12.1 671400 116823600
12
1.1.5.252 224.1.1.1 1.1.13.1 15840 2756160
20
1.1.9.254 224.1.1.1 1.1.13.1 670950 116745300
13
1.1.5.252 224.1.1.1 1.1.12.1 15840 2756160
20
1.1.9.254 224.1.1.1 1.1.11.3 671847 116901378
11
Total Entries: 9
Console> (enable)
This example shows how to display IP multicast MLS entries for a specific MMLS-RP and a specific multicast source address:
Console> (enable) show mls multicast entry rp 1.1.5.252 source 1.1.11.1
Router IP Dest IP Source IP Pkts Bytes
InVlan OutVlans
--------------- --------------- --------------- ---------- --------------------
------ -------------------------------------------------------
1.1.5.252 224.1.1.1 1.1.11.1 16080 2797920
20
Total Entries: 1
Console> (enable)
If you have a terminal that supports output that is 80-characters wide, you can use the long keyword to improve the appearance of the show mls multicast entry command output.
Console> (enable) show mls multicast entry long Router IP Dest IP Source IP Pkts Bytes InVlan OutVlans --------------- --------------- --------------- ---------- -------------------- ---------------------------- 1.1.5.252 224.1.1.1 1.1.11.1 61557 10710918 20 1.1.9.254 224.1.1.1 1.1.12.3 44040 7662960 12 20 1.1.5.252 224.1.1.1 1.1.12.3 60840 10586160 20 1.1.9.254 224.1.1.1 1.1.11.1 44490 7741260 11 20 1.1.5.252 224.1.1.1 1.1.11.3 61260 10659240 20 1.1.9.254 224.1.1.1 1.1.12.1 44040 7662960 12 20 1.1.5.252 224.1.1.1 1.1.13.1 60630 10549620 20 1.1.9.254 224.1.1.1 1.1.13.1 43590 7584660 13 20 1.1.5.252 224.1.1.1 1.1.12.1 61041 10621134 20 1.1.9.254 224.1.1.1 1.1.11.3 44490 7741260 11 20 Total Entries: 10 Console> (enable)
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.
Figure 45-2 shows one of the supported network topologies before and after IP multicast MLS is deployed (assuming a completely switched flow). The topology consists of a single switch, a single directly-connected external router, and multiple IP subnetworks (VLANs).
Figure 45-3 shows another supported network topology before and after IP multicast MLS is deployed (assuming a completely switched flow). The topology consists of a single switch, two external routers, and multiple IP subnetworks (VLANs).
A single MMLS-RP can support multiple MMLS-SEs provided the MMLS-RP is directly connected to both MMLS-SEs. In the network shown in Figure 45-3, flows from source G1 with destinations in VLANs 10 and 20 are multilayer switched. If any G1 destinations are in VLANs 100 or 200, the flow must be replicated in software by the router and forwarded by the switches. Similarly, if any G2 destinations are in VLANs 10 or 20, those flows are replicated in software by the router and forwarded by the switches.
Figure 45-4 shows another supported network topology before and after IP multicast MLS is deployed (assuming a completely switched flow). The topology consists of a single switch, multiple external routers, and multiple IP subnetworks (VLANs).
Figure 45-5 shows another supported network topology before and after IP multicast MLS is deployed (assuming a completely switched flow). The topology consists of a single switch, an internal RSM, and multiple IP subnetworks (VLANs).
IP multicast MLS does not support certain network topologies. Figure 45-6 shows one of the unsupported topologies. Multilayer switching is not possible because all multicast traffic from the G1 source must pass through the router to reach the destination G1 members. The switch only receives the multicast traffic after it is routed by the router.
Figure 45-7 shows another unsupported topology. IP multicast MLS is not possible because the MMLS-RP and MMLS-SE must be directly attached.
Figure 45-8 shows another unsupported topology. IP multicast MLS is not possible because multicast MLS is not supported over FDDI, ATM, and Token Ring connections. You must attach to external routers through Fast or Gigabit Ethernet interfaces.
These sections contain example IP multicast MLS implementations:
This example consists of these sections:
Figure 45-9 shows a basic IP multicast MLS example network topology. The network is configured as follows:
Without IP multicast MLS, when the G1 source (on VLAN 10) transmits 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.
After IP multicast MLS is implemented, when the G1 source transmits 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.
This example shows how to configure the router (MMLS-RP):
Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#ip multicast-routing Router(config)#interface fastethernet2/0.10 Router(config-subif)#encapsulation isl 10 Router(config-subif)#ip address 10.1.10.1 255.255.255.0 Router(config-subif)#ip pim dense-mode Router(config-subif)#interface fastethernet2/0.20 Router(config-subif)#encapsulation isl 20 Router(config-subif)#ip address 10.1.20.1 255.255.255.0 Router(config-subif)#ip pim dense-mode Router(config-subif)#interface fastethernet2/0.30 Router(config-subif)#encapsulation isl 30 Router(config-subif)#ip address 10.1.30.1 255.255.255.0 Router(config-subif)#ip pim dense-mode Router(config-subif)#mls rp ip multicast management-interface Warning: MLS Multicast management interface is now Fa2/0.30 Router(config-subif)#^Z Router#
This example shows how to configure the switch (MMLS-SE):
Console> (enable) set trunk 1/2 on isl Port(s) 1/2 trunk mode set to on. Port(s) 1/2 trunk type set to isl. Console> (enable) set igmp enable IGMP feature for IP multicast enabled Console> (enable) set mls multicast enable Multilayer Switching for Multicast is enabled for this device. Console> (enable) set mls multicast include 10.1.10.1 Multilayer switching for multicast is enabled for router 10.1.10.1. Console> (enable)
This example consists of these sections:
Figure 45-10 shows a more complex IP multicast MLS example network topology.
The network is configured as follows:
Without IP multicast MLS, when Server A (on VLAN 10) transmits 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.
After IP multicast MLS is implemented, when Server A transmits 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.
This example shows how to configure Router A (MMLS-RP):
Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#ip multicast-routing Router(config)#interface fastethernet1/0.1 Router(config-subif)#encapsulation isl 1 Router(config-subif)#ip address 172.20.1.1 255.255.255.0 Router(config-subif)#interface fastethernet1/0.10 Router(config-subif)#encapsulation isl 10 Router(config-subif)#ip address 172.20.10.1 255.255.255.0 Router(config-subif)#ip pim dense-mode Router(config-subif)#interface fastethernet1/0.20 Router(config-subif)#encapsulation isl 20 Router(config-subif)#ip address 172.20.20.1 255.255.255.0 Router(config-subif)#ip pim dense-mode Router(config-subif)#^Z Router#
This example shows how to configure Router B (MMLS-RP):
Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#ip multicast-routing Router(config)#interface fastethernet1/0.1 Router(config-subif)#encapsulation isl 1 Router(config-subif)#ip address 172.20.1.2 255.255.255.0 Router(config-subif)#interface fastethernet2/0.10 Router(config-subif)#encapsulation isl 10 Router(config-subif)#ip address 172.20.10.100 255.255.255.0 Router(config-subif)#ip pim dense-mode Router(config-subif)#interface fastethernet2/0.30 Router(config-subif)#encapsulation isl 30 Router(config-subif)#ip address 172.20.30.100 255.255.255.0 Router(config-subif)#ip pim dense-mode Router(config-subif)#^Z Router#
This example shows how to configure Switch A (MMLS-SE):
Console> (enable) set vlan 10 Vlan 10 configuration successful Console> (enable) set vlan 20 Vlan 20 configuration successful Console> (enable) set vlan 30 Vlan 30 configuration successful Console> (enable) set trunk 1/1 on isl Port(s) 1/1 trunk mode set to on. Port(s) 1/1 trunk type set to isl. Console> (enable) set trunk 1/2 on isl Port(s) 1/2 trunk mode set to on. Port(s) 1/2 trunk type set to isl. Console> (enable) set trunk 1/3 desirable isl Port(s) 1/3 trunk mode set to desirable. Port(s) 1/3 trunk type set to isl. Console> (enable) set trunk 1/4 desirable isl Port(s) 1/4 trunk mode set to desirable. Port(s) 1/4 trunk type set to isl. Console> (enable) set igmp enable IGMP feature for IP multicast enabled Console> (enable) set mls multicast enable Multilayer Switching for Multicast is enabled for this device. Console> (enable) set mls multicast include 172.20.10.1 Multilayer switching for multicast is enabled for router 172.20.10.1. Console> (enable) set mls multicast include 172.20.10.100 Multilayer switching for multicast is enabled for router 172.20.10.100. Console> (enable)
This example shows how to configure Switch B (assuming VTP is used for VLAN management):
Console> (enable) set igmp enable IGMP feature for IP multicast enabled Console> (enable)
This example shows how to configure Switch C (assuming VTP is used for VLAN management):
Console> (enable) set igmp enable IGMP feature for IP multicast enabled Console> (enable)
Posted: Mon Jul 19 12:47:21 PDT 1999
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