Multicast - Rate Limiting

SW1 -------- R3 ---------- R5

Here i make use of the multicast rate limiting function on R3 to control the amount of multicast traffic allowed to reach SW1.

First SW1 joins multicast groups 225.0.0.1 and 225.0.0.3

SW1
conf t
int fa0/0
ip igmp join-group 225.0.0.1
ip igmp join-group 225.0.0.3


On R3 the requirement is to limit the mcast traffic to 225.0.0.1 to 1k and 225.0.0.3 to 3k. The aggregate multicast traffic rate must not exceeed 5k.

This requirement can be achieved via the multicast rate limit function. Multiple rate limit statements can be applied to an interface and they are processed in a linear top down fashion. Hence careful consideration must be given to the order of the statements as applied.

First i use ACLS to define the mcast groups

R3
ip access-list standard GROUP_1
permit 225.0.0.1
ip access-list standard GROUP_3
permit 225.0.0.3

Then i apply the rate limit function.

interface FastEthernet0/0
ip multicast rate-limit out group-list GROUP_1 1
ip multicast rate-limit out group-list GROUP_3 3
ip multicast rate-limit out 5

After applying the mcast routes can be viewed and the bandwidth limits are shown

Router_3#s ip mroute 225.0.0.1
(*, 225.0.0.1), 00:13:28/00:02:33, RP 150.1.5.5, flags: SJC
Incoming interface: Serial2/0, RPF nbr 155.1.0.5
Outgoing interface list:
FastEthernet0/0, Forward/Sparse, 00:13:28/00:02:51, limit 1 kbps

Router_3#s ip mroute 225.0.0.3
(*, 225.0.0.3), 00:07:34/00:02:51, RP 150.1.5.5, flags: SJC
Incoming interface: Serial2/0, RPF nbr 155.1.0.5
Outgoing interface list:
FastEthernet0/0, Forward/Sparse, 00:07:34/00:02:51, limit 3 kbps


I then test the rate limiting via ping tests from R5. First i try a ping rate that conforms to the bandwidth limit.

Router_5#pin 225.0.0.1 size 100 repeat 2

Type escape sequence to abort.
Sending 2, 100-byte ICMP Echos to 225.0.0.1, timeout is 2 seconds:

Reply to request 0 from 155.1.37.7, 184 ms
Reply to request 0 from 155.1.37.7, 184 ms
Reply to request 1 from 155.1.37.7, 212 ms
Reply to request 1 from 155.1.37.7, 212 ms

Now i try a ping with an increased data size that exceeds the 1 kbps limit and, as expected, the traffic is dropped.

Router_5#pin 225.0.0.1 size 200 repeat 2

Type escape sequence to abort.
Sending 2, 200-byte ICMP Echos to 225.0.0.1, timeout is 2 seconds:
..


I repeat the above test on the mcast group 225.0.0.3 that has a higher bandwidth limit of 3k.

Router_5#pin 225.0.0.3 size 360 repeat 2

Type escape sequence to abort.
Sending 2, 360-byte ICMP Echos to 225.0.0.3, timeout is 2 seconds:

Reply to request 0 from 155.1.37.7, 208 ms
Reply to request 0 from 155.1.37.7, 212 ms
Reply to request 1 from 155.1.37.7, 268 ms
Reply to request 1 from 155.1.37.7, 268 ms
Router_5#pin 225.0.0.3 size 400 repeat 2

Type escape sequence to abort.
Sending 2, 400-byte ICMP Echos to 225.0.0.3, timeout is 2 seconds:
..
Router_5#