All things related to multicast

["Prashant Chopra" <>]

Thanks Dave.

> If Eugene is on this list please jump in as necessary.

RE: Do you have reason to believe the packet loss is due to congestion?  
Like the interfaces are really busy, or you have queues building on 
your routers, etc...   If not then QOS might not be an issue, it may be 
more fundamental problem.

> We found that the QoS headers are not being read by the Cisco routers. No
I don't really believe that the packet loss is due to congestion. We are
running GigE to the pillow. The network is mostly unutilized. 

> I agree it may be another problem like interfaces are really busy or
queues building on the routers. We are investigating these issues in
parallel. I will advise findings.

RE: By leaf nodes you mean client subnets off a router? 

> Yes.

RE: What are you  using for a router, and what code level? 

Cisco 6509, fully updated.

RE: I assume you are doing PIM Sparse Mode, etc...  Don't forget about
something as simple as duplex mis-match, it can cause all kinds of weird
problems, and TCP can mask it well.

> Yes we are investigating router and switch settings also. I will advise
findings.

Regards,
Prashant Chopra
Chief Architect
CampusEAI Consortium
1940 East 6th Street, 11th Floor
Cleveland, OH 44114
Tel:  216.589.9626
Mobile: 216.402.4505 
Fax:  216.589.9639 
Conference Line: 319.643.7750  Pin: 117423#
www.campuseai.org 


-----Original Message-----
From: David Farmer 
[mailto:]
 
Sent: Thursday, September 01, 2005 3:38 PM
To: Prashant Chopra; 

Cc: 

Subject: RE: Multicast QoS

Do you have reason to believe the packet loss is due to congestion?  
Like the interfaces are really busy, or you have queues building on 
your routers, etc...   If not then QOS might not be an issue, it may be 
more fundamental problem.

By leaf nodes you mean client subnets off a router?  What are you 
using for a router, and what code level?  I assume you are doing PIM 
Sparse Mode, etc...  Don't forget about something as simple as duplex 
mis-match, it can cause all kinds of weird problems, and TCP can 
mask it well.



On 1 Sep 2005 Prashant Chopra wrote:

> Colleagues,
> 
> Problem Statement 
> We have 6 multicast streams running at 1.6 Mbps. Clients connected to
> the leaf nodes are receiving really bad signal - very bad that there
> are more lost packets than received packets. Unicast works okay -
> transport is TCP not UDP. With Multicast, at a single hop from the
> server, clients receive everything just fine - no packet loss. This
> indicates that server is sending all the packets. But at the leaf
> nodes, things fall apart.
> 
> Question to Everybody
> > Do any of you have any experience of best practices with ToS
> > settings on
> the streaming server (Microsoft) and/or QoS settings on the networking
> side(Cisco)?
> 
> Our Troubleshooting Path
> We are doing some troubleshooting by trying out RTSPU to find out if
> there is a generic UDP issue instead of a Multicast UDP issue. This
> won't help much in resolving the issue, but might help isolate the
> scope of the problem.
> 
> Regards,
> Prashant Chopra
> Chief Architect
> CampusEAI Consortium
> 1940 East 6th Street, 11th Floor
> Cleveland, OH 44114
> Tel:  216.589.9626
> Mobile: 216.402.4505 
> Fax:  216.589.9639 
> Conference Line: 319.643.7750  Pin: 117423#
> www.campuseai.org 
> 
> 
> -----Original Message-----
> From: Alan Crosswell 
> [mailto:]
>  
> Sent: Wednesday, August 31, 2005 7:18 PM
> To: Prashant Chopra
> Subject: Re: Multicast QoS
> 
> Nope.  You could send your question to 
> 
> though /a
> 
> Prashant Chopra wrote:
> > Alan,
> > 
> >  
> > 
> > I was wondering if you are familiar with anyone that is
> > knowledgeable about Multicast QoS.
> > 
> >  
> > 
> > Regards,
> > 
> > Prashant Chopra
> > 
> > //Chief Architect//
> > 
> > **CampusEAI Consortium**
> > 
> > 1940 East 6th Street, 11th Floor
> > 
> > Cleveland, OH 44114
> > 
> > Tel:  216.589.9626
> > 
> > Mobile: 216.402.4505
> > Fax:  216.589.9639
> > Conference Line: 319.643.7750  Pin: 117423#
> > www.campuseai.org <http://www.campuseai.org/>
> > 
> >  
> > <mailto:>
> > 
> >  
> > 
> 
> 



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