WB1 8.25 Multicast Rate Limiting

8.25 Multicast Rate Limiting

• Configure R3 to limit the aggregate rate of the multicast traffic leaving the VLAN 37 interface to 1Mbps.
• Any source sending to the group IP 239.1.1.7 should be limited to 128Kbps.
• Multicast feeds from R6 to the IP address 239.1.1.100 should be limited to 256Kbps.

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You could use regular QoS policing and rate-limiting commands to control
multicast traffic flow. However, there is a special command for multicast traffic
rate control that has its own unique features. The command is
ip multicast rate-limit {in | out} [group-list <acl>] [source-list <acl>] [<limit>]
where limit is specified in Kilobits per second. The in
and out keywords control the ingress or egress traffic respectively. If you omit
the group-list and source-list, the limit will apply to the aggregate multicast traffic
rate, for all groups. However, if you omit the speed limit parameter, the command
will discard any multicast traffic matching both the group and source-list, if those
are specified. When applied without any parameters, this command will simply
drop all multicast traffic.

This command behaves differently when configured with group-list (and possible
source-list). When you designate the groups to be rate limited, the limit will apply
to each source/group pair individually. That is, if you configure the command to
limit the rate of traffic destined to the group 239.0.0.1 to 128Kbs and there are 3
independent sources, then the limit will apply to every source, resulting in 3x128
Kbps of aggregate rate.

You may combine the group-specific limits with the aggregate limit on the same
interface. This way, you will apply per-flow rate-limits and at the same time
control the aggregate rate. For example:

ip multicast rate-limit out group-list 100 128
ip multicast rate-limit out 512

Also, you may apply multiple group-specific multicast rate-limiting commands. In
this case, the particular (S,G) pair is limited based on the first match in the
configured access-lists. Notice that this restriction makes the order of the
statements particularly important! If you put the aggregate limit in the beginning
of the list, it will match everything and other entries will never be matched.

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R3:
ip access-list standard GROUP7
permit 239.1.1.7
!
ip access-list standard GROUP100
permit 239.1.1.100
!
interface FastEthernet0/0
ip multicast rate-limit out group-list GROUP7 128
ip multicast rate-limit out group-list GROUP100 256
ip multicast rate-limit out 1000

SW1:
interface FastEthernet0/3
ip igmp join-group 239.1.1.100

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To verify the limits, source some multicast packets to the groups 239.1.1.7 and
239.1.1.100. Then check the mroute states on R3. Notice that every group limit
appears next to the respective (S,G) entry:

Rack1R1#ping 239.1.1.7 repeat 10
Type escape sequence to abort.
Sending 10, 100-byte ICMP Echos to 239.1.1.7, timeout is 2 seconds:
Reply to request 0 from 155.1.37.7, 32 ms
Reply to request 0 from 155.1.37.7, 48 ms

Rack1R6#dddd
Translating "dddd"...domain server (255.255.255.255)
 (255.255.255.255)
Translating "dddd"...domain server (255.255.255.255)
% Unknown command or computer name, or unable to find computer address
Rack1R6#

Rack1R3#show ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report,
       Z - Multicast Tunnel, z - MDT-data group sender,
       Y - Joined MDT-data group, y - Sending to MDT-data group
Outgoing interface flags: H - Hardware switched, A - Assert winner
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode
(*, 239.1.1.100), 02:00:28/stopped, RP 150.1.8.8, flags: SJCL
  Incoming interface: FastEthernet0/0, RPF nbr 155.1.37.7
  Outgoing interface list:
    Serial1/0.1, Forward/Dense, 02:00:28/00:00:00
(155.1.146.6, 239.1.1.100), 00:00:17/00:02:58, flags: LJT
  Incoming interface: Serial1/0.1, RPF nbr 155.1.0.5
  Outgoing interface list:
    FastEthernet0/0, Forward/Dense, 00:00:17/00:00:00, limit 256 kbps
(*, 239.1.1.7), 00:05:05/stopped, RP 150.1.8.8, flags: SJCF
  Incoming interface: FastEthernet0/0, RPF nbr 155.1.37.7
  Outgoing interface list:
    Serial1/0.1, Forward/Dense, 00:05:05/00:00:00
(155.1.146.1, 239.1.1.7), 00:02:50/00:00:09, flags: JT
  Incoming interface: Null, RPF nbr 155.1.13.1
  Outgoing interface list:
    FastEthernet0/0, Forward/Dense, 00:02:50/00:00:00, limit 128 kbps    Serial1/0.1, Forward/Dense, 00:02:51/00:00:00, A
(155.1.0.1, 239.1.1.7), 00:05:05/00:01:51, flags: FT
  Incoming interface: Serial1/0.1, RPF nbr 0.0.0.0
  Outgoing interface list:
    FastEthernet0/0, Forward/Dense, 00:05:05/00:00:00, limit 128 kbps
(150.1.1.1, 239.1.1.7), 00:05:05/00:01:51, flags: JT
  Incoming interface: Serial1/0.1, RPF nbr 155.1.0.5
  Outgoing interface list:
    FastEthernet0/0, Forward/Dense, 00:05:05/00:00:00, limit 128 kbps
(*, 239.1.1.9), 01:59:35/00:02:25, RP 150.1.10.10, flags: SJC
  Incoming interface: FastEthernet0/0, RPF nbr 155.1.37.7
  Outgoing interface list:
    Serial1/0.1, Forward/Dense, 01:59:35/00:00:00
(*, 224.110.110.110), 02:00:34/00:02:59, RP 150.1.10.10, flags: SJCL
  Incoming interface: FastEthernet0/0, RPF nbr 155.1.37.7
  Outgoing interface list:
    Loopback0, Forward/Sparse-Dense, 02:00:34/00:02:59
    Serial1/0.1, Forward/Dense, 02:00:34/00:00:00
(*, 224.0.1.39), 02:00:25/00:02:45, RP 0.0.0.0, flags: DC
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    FastEthernet0/0, Forward/Dense, 02:00:25/00:00:00, Int limit 1000 kbps    Serial1/0.1, Forward/Dense, 02:00:25/00:00:00
(*, 224.0.1.40), 02:00:36/00:02:44, RP 0.0.0.0, flags: DCL
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    FastEthernet0/0, Forward/Dense, 02:00:36/00:00:00, Int limit 1000 kbps    Serial1/0.1, Forward/Dense, 02:00:36/00:00:00
Rack1R3#