Re: Service Instances and bridge domains MTU

Being that this is a test setup, I would sniff the traffic at both ports
of the ASR to make sure it is the one doing the filtering...
Using embedded packet capture it's easy to see that traffic is there at
the incomming port and not at the egress port.

-Carlos

P.D.
the original post had references to the xconnect thread messages,
sounding like a reply to one of them.

Eric campbell @ 11/05/2013 10:01 -0300 dixit:
> I think I may have unicast this back to Carlos by accident. here is my
> response for clarification on the issue. Thanks all.
>
>
> Eric
>
> If this turns out
> to be a double post I apologize.
>
>
> ________________________________
> From:
> Eric campbell <ericwcampbell_at_yahoo.com>
> To: Carlos G Mendioroz
> <tron_at_huapi.ba.ar>
> Sent: Saturday, May 11, 2013 8:57 AM
> Subject: Re: Service
> Instances and bridge domains MTU
>
>
>
> Carlos,
>
> Thanks for getting back to me.
> This is rather simple at the moment.
>
> I have an Adtran 8044 -> directly to the
> ASR on gig 0/1/1 the ASR then bridges this traffic to the interface Gig 0/1/2
> -> which then places it on the wire as a single tagged trunk going into a 6509
> trunk port and finally terminating on an SVI. On the other side of the Adtran
> is a simple laptop connected to the 8044 which is where I am originating the
> 1500 byte pings that terminate to the SVI on the 6509.
>
> The 8044 simply takes
> the packet in as a native packet in this case, applies a 802.1q tag to it, and
> then ships it out a trunk port to the ASR. The 8044 has a MTu set at 2000 on
> this port, The ASR has an interface level MTU of 1600 and the 6509 has an MTU
> of 1500. Also I have tried it with the MTu set at Max on the 6509 as
> well.
> Like I said I am sure that in a setup as small as this the answer is staring
> me in the eye.
>
> Since the 6509 is receiving a trunk port off of the ASr with
> a single tag applied I feel the problem is probably not there. The Adtran
> takes the taffic in from the laptop at 1500 MTU and then applies its tag then
> shipping it out.
>
> I have also tried performing this ping from a 7206 I have
> that is spare set up like the laptop in this case using the same parameters.
> Thanks for assisting
>
> Eric
>
> As far as I can tell this was a new post with a
> new problem. If somehow I emulated an existing thread then it was completely
> accidental.
>
>
>
>
>
>
>
> ________________________________
> From: Carlos G Mendioroz
> <tron_at_huapi.ba.ar>
> To: Eric campbell <ericwcampbell_at_yahoo.com>
> Sent:
> Saturday, May 11, 2013 8:28 AM
> Subject: Re: Service Instances and bridge
> domains MTU
>
>
> Eric,
> just to be clear, the ping works if DF bit is not set ?
> So someone is doing PMTU discovery since the ASR is only bridging.
> Would you
> share the whole topology and how you did determine that the
> ASR is the one
> filtering large frames ?
>
> BTW, starting a new thread by replying an old one
> leaves headers
> (References) that mail user agents use to missplace your post
> :(
>
> -Carlos
>
> Eric campbell @ 11/05/2013 08:01 -0300 dixit:
>> Folks,
>>
>> I
> just want to start off by saying thanks
> to all of the regulars in the group
> for the consistent knowledge sharing.
>>
>> I am a long time Lurker, but I
> have stumbled onto something which has me puzzled to say the least.
>>
>> I am
> attempting to create a bridge domain between two interfaces on an ASR 1006 and
> am running into a strange MTU issue.
>>
>> Everything is working fine I am
> tunneling my q-in-q/802.1q traffic popping and pushing the necessary tags and
> what not, however when I try to ping accross it using a 1500 byte packet with
> the df bit set i cannot. I can ping across it with a 1400 byte packet but of
> course this is not the magic number.
>>
>> I have tried setting the MTU at the
> interfaces involved (gig interfaces) but cannot for the life of me figure out
> why this is happening. This happens with a single tag as well as a stack of
> them. I do not have a BDI interface at the moment, but I am not sure i really
> need one since I am transiting
> the box. The only thing that i am able to
> think of at the momment is some sort of system wide MTU setting. This may
> become a no duh moment for me in the end, but I cannot find the command if it
> exists. Any guidance would be appreciated. If there is any information that is
> lacking let me know and i will get it out here.
>>
>> Thanks to all,
>> Eric
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
>>
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>>
>>
>>
>>
>

-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net