[c-nsp] Cisco 7600 multicast traffic - strange behavior

[Artyom Viklenko]

03.09.2010 14:34, Chris Evans пишет:
> Simple answer is that the group matches up to the link local MAC address
> block which is always used for 224.0.0.0/24 groups. Unfortunately the
> 7600/6500 does the filtering at layer two still, newer platforms typically
> do l3 filtering.  Groups x.0.0.0 x.128.0.0 match to the 00-01-5e-00-00-xx
> range.  There is a 32:1 overlap on MAC addresses for the mulicast addresses.
> These are always flooded. Best practice is to never use these ranges.
>
> Hope this helps.

Thank you Chris! Now I see what's wrong.
Finally found relevant document on Cisco's site.
So we need to re-number our milticast groups...

Thanks!


> On Sep 3, 2010 7:26 AM, "Artyom Viklenko"<artem at aws-net.org.ua>  wrote:
>
>> Hi, List!
>>
>> I need some help solving strange problem with multicast
>> traffic forwarding.
>>
>> At the main POP we have 7600 router which connected with
>> two TenGig interfaces to the main backbone ring in the
>> city. Port Gi3/2 connected to 3560G switch acting as a
>> multicast router for IPTV. Several PIM neigbors connected
>> to it via vlans passing through 7600 router. Yesterday
>> one customer bring up his PIM router and join
>> all multicast groups (total of 90 in range of 239.0.0.1
>> through 239.0.0.90). This lead to 400Mbit/s traffic from
>> 3560G switch through 7600 router in the customer's vlan.
>>
>> Backbone ring include other 7600 router and several 3750E
>> switches. This ring is L2 with MSTP.
>>
>> Later I found that main 7600 router sends all this multicast
>> traffic to all trunk ports containing customer's vlan including
>> two TenGig backbone ports and two other GigE ports.
>>
>> 7600 router runs 12.2(33)SRD4 Adv. IP Services.
>>
>> Mod Ports Card Type                              Model
>> --- ---- -------------------------------------- ------------------
>>   1   48  CEF720 48 port 1000mb SFP              WS-X6748-SFP
>>   2    8  CEF720 8 port 10GE with DFC            WS-X6708-10GE
>>   3   48  CEF720 48 port 10/100/1000mb Ethernet  WS-X6748-GE-TX
>>   5    2  Route Switch Processor 720 (Active)    RSP720-3CXL-GE
>>
>> Also, ip multicast routing switched on and MVPN vrf configured
>> on it - have plans to dismiss 3560G as multicast router.
>>
>> I try to find any glue in Cisco docs and google - no luck.
>>
>> Is it expected behavior or a bug, or misconfig of something.
>> Why router sends multicast traffic to all ports which members
>> of customer vlan? There is no igmp joins nor PIM traffic through
>> some of these ports.
>>
>> Please, point me in right direction.
>> Thanks!
>>
>> --
>>            Sincerely yours,
>>                             Artyom Viklenko.
>> -------------------------------------------------------
>> artem at aws-net.org.ua | http://www.aws-net.org.ua/~artem
>> artem at viklenko.net   | ================================
>> FreeBSD: The Power to Serve   -  http://www.freebsd.org
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>


-- 
            Sincerely yours,
                             Artyom Viklenko.
-------------------------------------------------------
artem at aws-net.org.ua | http://www.aws-net.org.ua/~artem
artem at viklenko.net   | ================================
FreeBSD: The Power to Serve   -  http://www.freebsd.org