Mailing List Archive: NANOG: users

multicast nightmare #42

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source_route at yahoo

Oct 14, 2009, 8:19 AM

Post #1 of 9 (626 views)
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multicast nightmare #42

Please explain how this would be possible:

1 sender
1 mcast group
1 receiver
----------------
= no data loss

1 sender
1 mcast group
2+ receivers on same VLAN and physical segment
--------------------
= data loss

aforestal at wolve

Oct 14, 2009, 8:21 AM

Post #2 of 9 (583 views)
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RE: multicast nightmare #42 [In reply to]

which mode?

-----Original Message-----
From: Philip Lavine [mailto:source_route [at] yahoo]
Sent: Wednesday, October 14, 2009 11:20 AM
To: nanog
Subject: multicast nightmare #42

Please explain how this would be possible:

1 sender
1 mcast group
1 receiver
----------------
= no data loss

1 sender
1 mcast group
2+ receivers on same VLAN and physical segment
--------------------
= data loss

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adrian.minta at gmail

Oct 14, 2009, 8:44 AM

Post #3 of 9 (578 views)
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Re: multicast nightmare #42 [In reply to]

Philip Lavine wrote:
> Please explain how this would be possible:
>
> 1 sender
> 1 mcast group
> 1 receiver
> ----------------
> = no data loss
>
> 1 sender
> 1 mcast group
> 2+ receivers on same VLAN and physical segment
> --------------------
> = data loss
>
>
>
Probably a crappy switch.

--
Best regards,
Adrian Minta

adrian at creative

Oct 14, 2009, 8:52 AM

Post #4 of 9 (582 views)
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Re: multicast nightmare #42 [In reply to]

On Wed, Oct 14, 2009, Adrian Minta wrote:

> >1 sender
> >1 mcast group
> >2+ receivers on same VLAN and physical segment
> >--------------------
> >= data loss

> Probably a crappy switch.

specifically, is your switch doing frame replication on ingress
or egress? :)

adrian

source_route at yahoo

Oct 14, 2009, 9:52 AM

Post #5 of 9 (580 views)
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Re: multicast nightmare #42 - REDUX [In reply to]

More info if this helps:

Switch Platform:
4500 SUPII+
with gig line cards

Data rate is <100Mbps

Server OS: Windows 2003 R2 (please withhold snickering).

----- Original Message ----
From: Philip Lavine <source_route [at] yahoo>
To: nanog <nanog [at] merit>
Sent: Wed, October 14, 2009 8:19:51 AM
Subject: multicast nightmare #42

Please explain how this would be possible:

1 sender
1 mcast group
1 receiver
----------------
= no data loss

1 sender
1 mcast group
2+ receivers on same VLAN and physical segment
--------------------
= data loss

adrian.minta at gmail

Oct 14, 2009, 10:36 AM

Post #6 of 9 (577 views)
Permalink

Re: multicast nightmare #42 - REDUX [In reply to]

Philip Lavine wrote:
> More info if this helps:
>
> Switch Platform:
> 4500 SUPII+
> with gig line cards
>
> Data rate is <100Mbps
>
> Server OS: Windows 2003 R2 (please withhold snickering).
>
>
Multicast traffic is routed ?

--
Best regards,
Adrian Minta

bensons at queuefull

Oct 14, 2009, 1:14 PM

Post #7 of 9 (578 views)
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Re: multicast nightmare #42 - REDUX [In reply to]

Is the packet loss uniform for each receiver? Or is there a pattern to
the loss, e.g. each receiver hears a different / non-overlapping 50%
of the packets?

Off the cuff, I'd suspect a problem with IGMP snooping.

Cheers,
-Benson

On 14 Oct 09, at 12:36 PM, Adrian Minta wrote:

> Philip Lavine wrote:
>> More info if this helps:
>>
>> Switch Platform:
>> 4500 SUPII+
>> with gig line cards
>>
>> Data rate is <100Mbps
>>
>> Server OS: Windows 2003 R2 (please withhold snickering).
>>
>>
> Multicast traffic is routed ?
>
> --
> Best regards,
> Adrian Minta
>
>

source_route at yahoo

Oct 15, 2009, 1:06 PM

Post #8 of 9 (555 views)
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Re: multicast nightmare #42 [In reply to]

Thank you Eric you are a genius, that has solved and issue that has plagued me for 3 years.

the problem was exactly as you said over subscription of the 8 ports tied to 1 ASIC

________________________________
From: Eric Ortega <eric_ortega [at] mmi>
To: Philip Lavine <source_route [at] yahoo>
Sent: Wed, October 14, 2009 9:51:43 AM
Subject: Re: multicast nightmare #42

Depending on the model of
blade there is an 8-to-1 over subscription on the 4500s. I have had all
kinds of headaches with this myself. The 48 port SFP "gig" blade can
only have 1 gig per each set of 8 ports. The aggregate ports are known
as "gigaports". The layout is gigaport 1 = 1,3,5,7,9,11,13,15 gigaport
2 = 2,4,6,8,10,12,14,16 and so on. I bet that if add up the total
bandwidth in each gigaport you might be over the "limit"

Philip Lavine wrote:
>
>I wish that was the case but the switch is a 4500 and the data
>rates are less than 100 mbps on a 1 gig blade/sup
>
>
>
>
________________________________
From: >Eric Ortega <eric_ortega [at] mmi>
>To: Philip Lavine
><source_route [at] yahoo>
>Sent: Wed, October 14,
>2009 8:24:59 AM
>Subject: Re: multicast
>nightmare #42
>
>Are you over subscribing
>either the link or the backplane of the switching device?
>
>>Philip Lavine wrote:
>
>Please explain how this would be possible:
>>
>>1 sender
>>1 mcast group
>>1 receiver
>>----------------
>> = no data loss
>>
>>1 sender
>>1 mcast group
>>2+ receivers on same VLAN and physical segment
>>--------------------
>>= data loss
>>
>>
>>
>>
>>
>
>--
>
>
>Eric R. Ortega
>Network Engineer
>Midcontinent Communications
>605.357.5720
>eric_ortega [at] gmail
>

--

Eric R. Ortega
Network Engineer
Midcontinent Communications
605.357.5720
eric_ortega [at] gmail

mksmith at adhost

Oct 15, 2009, 1:54 PM

Post #9 of 9 (553 views)
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RE: multicast nightmare #42 [In reply to]

As an aside, the 6-port GigE card is not oversubscribed.

Mike

--
Michael K. Smith - CISSP, GISP
Chief Technical Officer - Adhost Internet LLC mksmith [at] adhost
w: +1 (206) 404-9500 f: +1 (206) 404-9050
PGP: B49A DDF5 8611 27F3 08B9 84BB E61E 38C0 (Key ID: 0x9A96777D)

> -----Original Message-----
> From: Philip Lavine [mailto:source_route [at] yahoo]
> Sent: Thursday, October 15, 2009 1:07 PM
> To: Eric Ortega; nanog
> Subject: Re: multicast nightmare #42
>
> Thank you Eric you are a genius, that has solved and issue that has
> plagued me for 3 years.
>
> the problem was exactly as you said over subscription of the 8 ports
> tied to 1 ASIC
>
>
>
>
> ________________________________
> From: Eric Ortega <eric_ortega [at] mmi>
> To: Philip Lavine <source_route [at] yahoo>
> Sent: Wed, October 14, 2009 9:51:43 AM
> Subject: Re: multicast nightmare #42
>
> Depending on the model of
> blade there is an 8-to-1 over subscription on the 4500s. I have had
all
> kinds of headaches with this myself. The 48 port SFP "gig" blade can
> only have 1 gig per each set of 8 ports. The aggregate ports are known
> as "gigaports". The layout is gigaport 1 = 1,3,5,7,9,11,13,15 gigaport
> 2 = 2,4,6,8,10,12,14,16 and so on. I bet that if add up the total
> bandwidth in each gigaport you might be over the "limit"
>
> Philip Lavine wrote:
> >
> >I wish that was the case but the switch is a 4500 and the data
> >rates are less than 100 mbps on a 1 gig blade/sup
> >
> >
> >
> >
> ________________________________
> From: >Eric Ortega <eric_ortega [at] mmi>
> >To: Philip Lavine
> ><source_route [at] yahoo>
> >Sent: Wed, October 14,
> >2009 8:24:59 AM
> >Subject: Re: multicast
> >nightmare #42
> >
> >Are you over subscribing
> >either the link or the backplane of the switching device?
> >
> >>Philip Lavine wrote:
> >
> >Please explain how this would be possible:
> >>
> >>1 sender
> >>1 mcast group
> >>1 receiver
> >>----------------
> >> = no data loss
> >>
> >>1 sender
> >>1 mcast group
> >>2+ receivers on same VLAN and physical segment
> >>--------------------
> >>= data loss
> >>
> >>
> >>
> >>
> >>
> >
> >--
> >
> >
> >Eric R. Ortega
> >Network Engineer
> >Midcontinent Communications
> >605.357.5720
> >eric_ortega [at] gmail
> >
>
> --
>
>
> Eric R. Ortega
> Network Engineer
> Midcontinent Communications
> 605.357.5720
> eric_ortega [at] gmail
>
>
>

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