> I needed to use this command the other day, I have an 887VA-M and the BT > FTTC product, I bypassed the BT modem and connected directly into the BT > wall socket with the 887VA-M as it has a VDSL interface (just a config > tweek) > > The config I was using was PPPOE which adds 8 bytes to the frame so on my > dialer0 I set the mtu to 1492, without the 'ip tcp adjust-mss 1452' I could > not open web pages or run speed tests as my local host's mtu defaulted to > their local setting (1500) and was dropped.
You really shouldn't have to do this. BT 21CN supports baby-jumbos to give you the extra 8 bytes of PPPoE on top of a 1500-byte IP packet. Raising MTU on the physical Ethernet interface facing the BT modem definitely works, I can get 1500-byte DF-set IP packets to and from the Internet; you should be able to do the same on the VDSL interface. Regards, Tim. _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
