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New Member

Reason to configure Multicast Address in a switch

I have found the following lines in a Cat5500:

set cam permanent 01-00-5e-7a-1a-01 1/1-2 301

set cam permanent 01-00-5e-7a-1a-01 11/19 301

set cam permanent 01-00-5e-7a-1a-01 12/3 301

set cam permanent 01-00-5e-7a-1a-02 1/1-2 303

Can anyone tell why we need thsi configuration. 01-00-5e seems to be a multicast address to me, but what is the reason behind that.Appreciate an feedback on this. Thanks.Edmond

2 REPLIES
Cisco Employee

Re: Reason to configure Multicast Address in a switch

Looks like sombody has configured them statically rather than using CGMP.

http://www.cisco.com/warp/public/473/cat_multicast_prob.html#solu4

With CGMP or the above configuration, multicast traffic will not be flooded in the VLAN but constrained to those ports.

New Member

Re: Reason to configure Multicast Address in a switch

Thanks for the excellent response. Now I understand why the command existed. However my real problem is some of the permanent Mac entries for access port are claimed to be lost after switch rebooted. teh entries for ISL ports for retained. I am still struggling to identify whether this is h/w related as the entries should be stored in the NVRAM of the switch, but why only paticular parts are missing.

Appreciate any futher advice. Edmond

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