multicast

[manoj_pu]

Hi,

Is it possible to disable multicasting so that I can reduce network trafic.

"ifconfig" command shows MULTICAST with ethernet interface what does it means??

#ifconfig lan0
lan0: flags=843
inet 190.9.200.200 netmask ffff0000 broadcast 190.9.255.255


Any hint on this greatly appreciable

Manoj

[K.Vijayaragavan.]

I think we can disable multicast at port level in the switch/router to where your system is connected.

see the link for more info on this.
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat5000/rel_5_2/config/bcastsup.htm#10299

-Vijay

[Helen French]

Hey Manoj P.U =))

Check this out:

http://www.docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90105/B2355-90105_top.html&con=/hpux/onlinedocs/B2355-90105/00/00/40-con.html&toc=/hpux/onlinedocs/B2355-90105/00/00/40-toc.html&searchterms=multicasting&queryid=20020220-061545

http://www.docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90147/B2355-90147_top.html&con=/hpux/onlinedocs/B2355-90147/00/00/78-con.html&toc=/hpux/onlinedocs/B2355-90147/00/00/78-toc.html&searchterms=multicasting&queryid=20020220-061545

HTH,
Shiju

[harry d brown jr]

Personally I'd wait for Rick Jones to respond, because there might be some ndd setting, but until then look at mrouted.


live free or die
harry

[Helen French]

Manoj,

See this, it may help you:

http://www.docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B9106-90008/B9106-90008_top.html&con=/hpux/onlinedocs/B9106-90008/00/02/243-con.html&toc=/hpux/onlinedocs/B9106-90008/00/02/243-toc.html&searchterms=multicasting&queryid=20020220-061827


HTH,
Shiju

[Helen French]

Manoj P Unni =))

Again, see this too:

http://www.docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90691/B2355-90691_top.html&con=/hpux/onlinedocs/B2355-90691/00/02/232-con.html&toc=/hpux/onlinedocs/B2355-90691/00/02/232-toc.html&searchterms=multicasting&queryid=20020220-061545

http://www.docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90681/B2355-90681_top.html&con=/hpux/onlinedocs/B2355-90681/00/02/206-con.html&toc=/hpux/onlinedocs/B2355-90681/00/02/206-toc.html&searchterms=multicasting&queryid=20020220-061545

HTH,
Shiju

[K.Vijayaragavan.]

see the commands,

#ndd -h unsupported

or

#ndd -h unsupported | grep ip_respond_to_echo_broadcast

we can disable multicast by issu ing the below mentioned command but man page of ndd says it is not suggested. But if none of the software or os part is using this then you may diable if you decide to do so.

/ndd -set /dev/ip ip_respond_to_echo_broadcast 0

-Vijay

[Ron Kinner]

I expect all that the multicast indicates is that the NIC and its driver can handle multicasts. That means you can join a multicast group and receive a multicast broadcast. It does not mean that your PC is multicasting and loading up the LAN with extra packets.

Unless you have specifically joined a multicast group or are running mrouted and are relaying multicasts from one network to another the multicast capability of your PC has no effect on your network.

Default TTL on a multicast is 1 so it won't be routed accidentally.

You can also look at mrinfo or at the igmp stats in netstat -s to see what is going on in multicast.

Look at
lanadmin
lan
display

then compare the number of inbound unicast packets received with the number of inbound non-unicast packets received. Cisco recommends that this ratio should be about 5 to 1 or better. Look at the outbound ratio to see if your PC is contributing to the problem.

If your network is full of trash broadcasts you might need to look for Windows machines running netbeui or netware or Compaq PCs running their stupid diagnostic manager software. Put a sniffer on it and see what sort of stuff you are seeing.

If it is a performance issue then make sure that you are not relying on autonegotiate to set the speed and duplex. This should be set manually on both ends of the circuit on all circuits.

Ron