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Multicast traffic

I'm trying to get some discussion on what amount of multicast traffic is too much, and how it can be contained or stopped on an interface. I'm posting the results of a 'sho int' from an internet facing router in my network.

GigabitEthernet0/1 is up, line protocol is up

Hardware is BCM1125 Internal MAC, address is 0017.9525.d251 (bia 0017.9525.d251)

Description: "to IPS TWTC cable 1"

Internet address is

MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

reliability 255/255, txload 11/255, rxload 4/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 1000Mb/s, media type is RJ45

output flow-control is XON, input flow-control is XON

ARP type: ARPA, ARP Timeout 04:00:00

Last input 00:00:00, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 701

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 15970000 bits/sec, 6261 packets/sec

5 minute output rate 46324000 bits/sec, 7216 packets/sec

1585653950 packets input, 2159729978 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

1 input errors, 0 CRC, 0 frame, 1 overrun, 0 ignored

0 watchdog, 23675 multicast, 0 pause input

0 input packets with dribble condition detected

1901197083 packets output, 3193928813 bytes, 0 underruns

4 output errors, 0 collisions, 5 interface resets

0 babbles, 0 late collision, 0 deferred

4 lost carrier, 0 no carrier, 0 pause output

0 output buffer failures, 0 output buffers swapped out


Re: Multicast traffic

"Too Much Multicast" is one of those awkward questions. A quick look at the inbound there shows multicast as <1%. That's not much.

If it is a concern it might be better to try to capture some to see what the traffic actually is.

What routing protocol are you using? Remember OSPF, EIGRP , RIPv2 etc all use IPmulticast, along with numerous other protocols that use Multicast at either layer three or two.