Hi Alls.
we've got an issue of internet slowness from branch office. HQ internet access has no issue. Between HQ and branch is connected with GRE.
However, recently, branch office has been asked us to check the internet connectivity. below is GRE tunnel status.
Tunnel10 is up, line protocol is up
Hardware is Tunnel
Description: Tunnel to ----
Internet address is x.x.x.x/30
MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec,
As above, MTU is 1514. mean that if the packet goes via HQ from branch office, they must encapulated GRE header. and the packet size is 1538.
in this worse, the packet is fragmentated, right?
So, we have to pre-define MTU and MSS size. this is my knowledge from before.
Please, let me know if you have better troubleshooting guide regarding GRE MTU issue.
Thanks you.