2011/7/12 Gert Doering <[email protected]>
> Hi, > > On Tue, Jul 12, 2011 at 07:46:00PM +0000, Leigh Harrison wrote: > > There is a legacy layer 2 network which has had an mpls network > > built over it. A link between two of the data centres is a dark > > fibre between two Cisco 3750E switches running on the ten gig ports > > with a variety of vlans passing over a dot1q trunk. Both of these > > switches are pretty much out of the box and have a standard system > > mtu of 1500 > > You have an MTU problem. If you want to send (1500 byte + extra header > bytes) packets over a link with a MTU of 1500 -> FAIL. > > gert > > It's actually going to be 1500 - header sizes. So 1500 - MPLS (4bytes) = 1496 possibly - IPSEC (20 Bytes) = 1476 _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
