Folks,
I keep reading in this forum that in an MPLS network if the MTU is 1500 bytes (default), a lot of packets would get dropped as the labels added to the original packet make it bigger than 1500 bytes(4 bytes per lable).
So i did a test today, I built a small network of three routers. I connected one of the routers to the internet and connected my laptop of the 3rd router on the far end. Had the router connected to the internet advertise a default route in a vrf to the router on the far end. I made sure that my traffic was being tag switched inside the core before going to the internet.
All interfaces inside my core had only 1500 mtu set.
to my surprise, i was able to go to yahoo, msn, hotmail, cnn and many other sites without any problem.
Does anyone know of a site that marks the packet as df=1 so that it is not fragmented inside the core?
I used the extended ping test with mtu of 1504 and df=1 and it failed as suspected.
does anyone know of an other application I can use to prove that mtu of 1500 would not work in an MPLS network rather than using a ping?
How will i know that packets were dropped because the mtu was more than the interface that support?
Thanks
