There's no such thing as Ethernet fragmentation. There's no sequence number field or next frame packet headers and no control message protocol to control it. You could create a gre tunnel and set the MTU and/or fragmentation there.
Sent from my iPhone On Mar 6, 2011, at 6:41 AM, Mohammad Salbad <salbad1...@hotmail.com> wrote: > Hello All > > > > I have two EX4200 switches connected back to back to each other with > interfaces in trunk mode as following: > > Case(1) back to back connection using ethernet cable > > (VL11 IP: 10.1.1.1/30) EX4200 -------------------TRUNK > (Ethernet)---------------------EX4200 (VL11 IP: 10.1.1.2/30) > > è For this case I can ping with don’t fragment option up to 1554 byte as > following: > > ping 10.1.1.2 size 1554 do-not-fragment > > PING 10.1.1.2 (10.1.1.2): 1554 data bytes > > 1562 bytes from 10.1.1.2: icmp_seq=0 ttl=64 time=3.639 ms > > 1562 bytes from 10.1.1.2: icmp_seq=1 ttl=64 time=3.550 ms > > 1562 bytes from 10.1.1.2: icmp_seq=2 ttl=64 time=3.556 ms > > Case(2) back to back connection using wireless backhaul devices > > (VL11 IP: 10.1.1.1/30) EX4200 -------------------TRUNK (wireless > backhaul)---------------------EX4200 (VL11 IP: 10.1.1.2/30) > > è For this case I can ping with don’t fragment option up to 1476 byte as > following: > > ping 10.1.1.2 size 1476 do-not-fragment > > PING 10.1.1.2 (10.1.1.2): 1476 data bytes > > 1484 bytes from 10.1.1.2: icmp_seq=0 ttl=64 time=4.096 ms > > 1484 bytes from 10.1.1.2: icmp_seq=1 ttl=64 time=4.094 ms > > 1484 bytes from 10.1.1.2: icmp_seq=2 ttl=64 time=5.496 ms > > > > Switches configuration sample > > ge-0/0/1 { > > mtu 1600; > > ether-options { > > link-mode full-duplex; > > speed { > > 100m; > > } > > } > > unit 0 { > > family ethernet-switching { > > port-mode trunk; > > vlan { > > members [ TEST ]; > > } > > } > > } > > vlan { > > mtu 1600; > > unit 11 { > > family inet { > > address 10.1.1.1/30; > > } > > } > > vlans { > > TEST { > > vlan-id 11; > > } > > > > The case is that I didn’t change the configuration on the switches I just > replaced the Ethernet cable with wireless backhaul devices and then I can’t > ping with larger mtu sizes, and this is because the wireless devices I’m > using for backhaul are limited to 1500 MTU size, so I’m wondering if I there > is anything I can do on the switches to overcome the limitation on the > wireless backhaul devices, i.e. if I can fragment the packet into smaller > pieces before sending them to the wireless device and combining the packet > on the other end (something like link fragmentation and interleaving). > > > > Thank you > > Mohammad Salbad > > _______________________________________________ > juniper-nsp mailing list juniper-nsp@puck.nether.net > https://puck.nether.net/mailman/listinfo/juniper-nsp _______________________________________________ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp