First I would apologize to the other poster for inadvertently Hijacking his thread.
I will start a new thread at this point and maybe That will work. 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 moment 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. This is a rather small test environment 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 Thanks to all, Eric _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com http://onlinestudylist.com/mailman/listinfo/ccie_rs
