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New Member

Bridge over Multilink cannot forward big packets

I need to connect 7513 to 7507 by 2*E1,I may the 2*e1 in a Multilink,and configure the Multilink to bridge-group,Interface Mutlilink can bundle ,I can Ping when the packets smaller than 1496Bytes ,when the Ping's packets begger than 1496(i.e.1500)Bytes ,then the Ping will timeout.

If the Multilink just have one E1,then they do well.

the 7513 config like that:

bridge cbr

bridge-group 1 protocol ieee

interface Multilink 1

ppp multilink

multilink-group 1

ppp multilink interleave

bridge-group 1

interface s8/1/3:0

en ppp

ppp multilink

multilink-group 1

interface s8/1/4:0

en ppp

ppp multillink

multilink-group 1

interface f4/0/1

bridge-group 1

And the 7507 just like that.

Anyone have some suggestions will very thanks .


Re: Bridge over Multilink cannot forward big packets

If the packets bigger than 1496 bytes are being dropped, it should be a problem with MTU or fragmentation. Check if the DF bit is set and hence packets are dropped. Increasing the mtu should solve the problem.

New Member

Re: Bridge over Multilink cannot forward big packets

Thank your reply.

I note when the PING TIMEOUT then the lost fragments will increase ,just like that:

sh pp multilink

Multilink1, bundle name is backup

Bundle up for 00:27:17

Bundle is Distributed

33 lost fragments, 1222 reordered, 0 unassigned

0 discarded, 0 lost received, 1/255 load

0x1F received sequence, 0x371 sent sequence

Member links: 2 active, 0 inactive (max not set, min not set)

Se8/1/4:0, since 00:28:07, no frags rcvd

Se8/1/3:0, since 00:01:00, no frags rcvd

The CISCO DE think that is a BUG,but i change the MTU(1498 or 1550)and the Symptoms persists ,the BUG is CSCed09364