All things related to multicast

["Ying Zhang" <>]

----- Original Message ----- 
From: "Bill Owens" <>
To: "Ying Zhang" 
<>
Cc: "wg-multicast" 
<>
Sent: Thursday, September 24, 2009 12:03 PM
Subject: Re: 239.255.255.250 address


> On Thu, Sep 24, 2009 at 11:49:09AM -0300, Ying Zhang wrote:
> > Hi list,
> >
> > We have PIM-SM enabled on our network. Recently we've seen tons of log 
> > messages on our switch:
> >
> > CPU5 [09/24/09 14:21:47] IPMC ERROR ipmSysAddSession FAIL: Ar AddIpmcRec 
> > S x.x.96.47 G 239.255.255.250
> > CPU5 [09/24/09 14:21:47] IPMC WARNING ipmSysArAddIpmcRec rarAddIpmc FAIL 
> > G 239.255.255.250 !
> > CPU5 [09/24/09 14:21:47] IPMC WARNING k_chg_mfc FAIL New Session 
> > x.x.96.47 239.255.255.250 is failed
> >
> >  This has caused our switch to act slow and even drop some SNMP packets. 
> > I did some search and found out it's SSDP for Windows Universal Plug and 
> > Play.  On the mcast routing table, I can see many other users using the 
> > same protocol, but only a few were logged with the error messages. I 
> > suspect the user OS was affected by some virus. Just wondering if anyone 
> > else has seen this and how to fix it on our end.
>
> Without having docs for those error messages it's hard to tell, but it 
> looks as though the switch (which is also the PIM designated router?) is 
> trying to create state for a new source. "SysAddSession" with an S and a G 
> looks like a higher-level function, and Google says that k_chg_mfc is a 
> function in pimd to add a forwarding cache entry.
>
> Does the switch/router have some built-in or configured limit on how many 
> sources/receivers/groups it can support? Or maybe just a memory 
> limitation?

We don't have a large user base. The cache was only like under 20 entries. 
But I will dig more into the memory limitation. Thanks for the answer.

Ying
> Bill.