When Multicast is not impelemented

[jcowtan]

I have a customer who is not using multicast. We do not plan to implement it.

We are running 6509, 4506 and 3750 as our switches. What happens to multicast traffic at the switch when we have not defined anything?

- No forwaring?

- all ports forwarding?

[milan.kulik]

Flooding to all ports, which can bring your network into troubles in a case of huge multicast traffic.

See

http://forums.cisco.com/eforum/servlet/NetProf?page=netprof&CommCmd=MB?cmd=pass_through&location=outline@^1@@.ee93165/7#selected_message

for a workaround solution example.

Regards,

Milan

[jcowtan]

I am unable to get to the reference site. Has it been correctly named?

[Richard Burts]

You will not get there by simply clicking the URL because the URL is incomplete (essentially it looks like there was line wrap when the answer was submitted). Look beyond the indicated URL and make sure that you paste all of that text into your browser and it should get you there.

HTH

Rick

[jcowtan]

So in designing, what is a best practice when multicast is not being used/planned for?

[milan.kulik]

Aa far as multicasts are not being used/planned, I wouldn't care too much about them.

If you want be "paranoid", you can prevent their flooding using IGMP, CGMP as discussed in http://www.cisco.com/warp/public/473/38.pdf

http://www.cisco.com/warp/public/473/22.pdf

Some other multicast documents:

http://www.cisco.com/warp/public/732/Tech/multicast/multicast_techdoc.shtml

Regards,

Milan