Hello, I have come across a strange issue between a cisco 7206VXR (NPE-G1) and a cisco OSR-7609 (R7000). I try to Ping from 7206 VXR to 7609 with different MTU sizes and DF bit set. All MTU sizes on ports and VLANs are set for Jumbo frames (Sizes > 4470 Bytes). Please note that 7609 perfoms Inter-VLAN routing betwen VLAN65 and 300 and G0/2 port of the 7206VXR is on VLAN 300.
This is what I get when I ping from 7206VXR source G0/2 (VLAN 300) on interface VLAN 65 IP address:
proto720e#ping X.X.176.1 size 1500 source g0/2 df-bit
Type escape sequence to abort.
Sending 5, 1500-byte ICMP Echos to X.X.176.1, timeout is 2 seconds:
Packet sent with a source address of X.X.224.2
Packet sent with the DF bit set
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms
but with size 1501:
proto720e#ping X.X.176.1 size 1501 source g0/2 df-bit
Type escape sequence to abort.
Sending 5, 1501-byte ICMP Echos to X.X.176.1, timeout is 2 seconds:
Packet sent with a source address of X.X.224.2
Packet sent with the DF bit set
.....
Success rate is 0 percent (0/5)
Once I ping to Interface VLAN 300 on 7609 with large MTU size from 7206 VXR there is no prob whatsoever, I get a reply:
proto720e#ping 80.107.224.1 size 1550 source g0/2 df-bit
Type escape sequence to abort.
Sending 5, 1550-byte ICMP Echos to X.X.224.1, timeout is 2 seconds:
Packet sent with a source address of X.X.224.2
Packet sent with the DF bit set
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms
Therefore there must be an Issue with Inter-VLAN routing, is anyone aware of any bugs associated with it or any workarounds, thanks a lot
Tony
