Howard,
We have encountered issues in the past with multicast. The switches
cache IGMP membership so that the router only holds one entry for a multicast
address against one IP address. Then when a device sends an IGMP leave that
makes it to the router so it removes that multicast address from its forwarding
table. As the other devices stop seeing the stream they send IGMP joins so the
router adds its again to its table and then all devices receive the feed. The
following is an example from our CISCO router which is sending multicast TV to
our Enterasys switches and it only holds a single entry per vlan even though
more than one device ihas actually joined the stream.
cophub#sh ip igmp membership 239.224.0.9
Flags: A - aggregate, T - tracked
L - Local, S - static, V - virtual, R - Reported through v3
I - v3lite, U - Urd, M - SSM (S,G) channel
1,2,3 - The version of IGMP, the group is in
Channel/Group-Flags:
/ - Filtering entry (Exclude mode (S,G), Include mode (G))
Reporter:
<mac-or-ip-address> - last reporter if group is not explicitly tracked
<n>/<m> - <n> reporter in include mode, <m> reporter in exclude
Channel/Group Reporter Uptime Exp. Flags Interface
*,239.224.0.9 192.168.222.213 02:04:40 00:21 2A Vl789
*,239.224.0.9 192.168.227.162 04:00:46 00:23 2A Vl792
*,239.224.0.9 192.168.228.58 15:42:40 00:21 2A Vl793
This would cause TV feeds to start and stop as people channel surf
sending IGMP leaves. We solved it by writing a policy that ignores all IGMP
leaves, then wait for the membership query timeout to stop sending the stream.
Cheers
Darren
> Hi all,
>
> We have just upgraded our Network to S8 at the core and C5 stacks at the edge
> with dual 10Gb links. We had some issues throughout the implementation but
> were able to fix all except one. We are having issues with Ghost multicast.
> The ghosting works fine with a few computers (4 and under) but when we start
> a classroom it does not make it through a complete ghost session and crashes
> at various points. We have been working with GTAC the last few days but they
> seem to be stumped.
> Thanks.
> Howard Dansky
> Director Telecom and Network Services
> Broward College
> 225 East Las Olas Blvd
> Ft Lauderdale, FL 33301
> (: 954-201-7524 | 7: 954-201-7348 | *: [email protected]
>
> From: John Kaftan [mailto:[email protected]]
> Sent: Sunday, August 12, 2012 8:51 PM
> To: Enterasys Customer Mailing List
> Cc: Enterasys Customer Mailing List
> Subject: Re: RE: RE:[enterasys] DHCP Option 43 - AP3610 - Email found in
> subject
>
> I use option 78 as well. I have two controllers and the APs try to connect
> to both of them. When I connect a new AP it shows up on both controllers a
> "Pending" and I just approve it on the controller that I want it to be local
> on. It works perfectly.
>
> John
>
> ----- Original Message -----
> From: Michael Votaw - ASI <[email protected]>
> Date: Sunday, August 12, 2012 8:27 pm
> Subject: RE: RE:[enterasys] DHCP Option 43 - AP3610 - Email found in subject
> To: Enterasys Customer Mailing List <[email protected]>
>
> > I'm sure that some people have gotten Option 43 to work, but I
> > use option 78 and DNS in my installs. DNS is great when
> > you have only one controller and is easy to setup. I will
> > use option 43 when I have two or more controllers and I need to
> > "steer" APs to a particular controller when all of those APs
> > share a common DNS server.
> >
> > A talented engineer from Enterasys posted this doc some time ago...
> >
> > -----Original Message-----
> > From: [email protected] [mailto:[email protected]]
> > Sent: Friday, August 10, 2012 6:11 PM
> > To: Enterasys Customer Mailing List
> > Subject: RE:[enterasys] DHCP Option 43 - AP3610 - Email found in
> > subject
> > Erik,
> >
> > Thank you for the DNS hint.
> > I think it is the best solution for Remote site with MPLS
> > connectivity and I will give it a try
> > ---
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> >
> > ---
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>
> I will be out of the office today 5/10/2012 and will be returning tomorrow.
>
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