Re: [DLC]Multicast
Scott Behrens <[email protected]> Tue, 16 Mar 2010 07:34:26 -0500
| Newsgroups | gmane.org.user-groups.linux.depaul-lug |
|---|---|
| Message-ID | <[email protected]> |
Everyone, Thanks for the helpful information. Scott Behrens On Mon, Mar 15, 2010 at 7:28 PM, Matthew P Kemp <[email protected]> wrote: > Thanks John... of course by "handling IGMP" I thought I had eluded to > IGMP snooping and (*eek* CGMP). As a personal rule, vendor specific > protocols that 'assist' or 'replace' other standards; are typically > not a good choice to make. > > -- > Matthew P Kemp > > > > On Mon, Mar 15, 2010 at 2:39 PM, John Kristoff <[email protected]> wrote: >> On Mon, Mar 15, 2010 at 01:58:46PM -0500, Matthew P Kemp wrote: >>> Typically when you look at multicast you are looking at the routers >>> (unless the switch is handling IGMP), the switch typically treat >>> multi-cast traffic as if were a broadcast. The Ethernet card is just >> >> Depending on the switch, it may support something generically called >> IGMP snooping, which means the switch will try IP multicast packets >> a bit differently than broadcast. With snooping, the switch will >> forward group messages only to ports that have expressly indicated >> interest in the group with a IGMP message. Cisco switches also have >> something called CGMP. There has been a history of potential issues >> with IGMP snooping. Basically anytime you start forcing your so-called >> L2 device to start examining L3 or higher info, things get tricky. For >> example, there was a problem with Cisco switches flooding multicast >> (basically like a broadcast storm) whenever there was a spanning tree >> topology change. In large-use streaming multicast environments, that >> would cause all sorts of reliability and performance issues. >> >> John >> _______________________________________________ >> DLC mailing list >> [email protected] >> http://mailman.depaul.edu/mailman/listinfo/dlc >> Use the Above Link to Unsubcribe!! >> http://linux.depaul.edu/ >> > _______________________________________________ > DLC mailing list > [email protected] > http://mailman.depaul.edu/mailman/listinfo/dlc > Use the Above Link to Unsubcribe!! > http://linux.depaul.edu/ > _______________________________________________ DLC mailing list [email protected] http://mailman.depaul.edu/mailman/listinfo/dlc Use the Above Link to Unsubcribe!! http://linux.depaul.edu/