Cat 4500 GRE Tunnel performances

[helenio]

Hello, I have som performances issues with a GRE Tunnel on 4500 (12.2(37)SG with Supervisor V).

I think that GRE Tunnel is performed on SW, isn't ?

Does someone know the max throughput that we can get on that tunnel ?

I'm afraid that fragmentation can also decrease the performances, ho can I check the number of fragmented packet on that tunnel ?

[Hitesh Vinzoda]

hi,

Its true that GRE packets are process switched in 4500 series switches running with any codes  i.e Switched in software. I think it will give you performance between 5 to 15 Mbps at max. It may also lead to high CPU utilization during the specified data rates.

HTH

Hitesh Vinzoda

[Giuseppe Larosa]

Hello Helenio,

use of GRE tunnels on a Cisco 4500 is not recommended it would lead to very high cpu usage with rather poor performances.

We also noticed that is not possible to move traffic in a VRF using a GRE tunnel in VRF.

What is your scenario?

Hope to help

Giuseppe

[helenio]

I'm using GRE tunnel cause I have to set up a EIGRP comunication over VPN-IPsec (2x Fortigate FWs). I did a test and I had 70% CPU with 40 Mbps traffic.

Do you see another way to establish a EIGRP Neighborship trhough a VPN IPsec Tunnel ?

For the VRF you mean that you can't assign a Tunnel to a VRF other that the Global one ?

[paolo bevilacqua]

As Giuseppe mentioned above, you must use router not switches for tunnels.

[helenio]

Where can I fing Tunnel performances based on RTR Model ?

[Giuseppe Larosa]

Hello Helenio,

use the following PDF, a newer version exists including new G2 ISR routers.

Hope to help

Giuseppe

[helenio]

Thank's ... Tunnel GRE in Routers is done in Fast/CEF ? ...

[Giuseppe Larosa]

Hello Helenio,

yes sw based routers have no dramatic performance penalties when handling GRE tunnels.

CEF for tunnel GRE should be supported in recent IOS releases

Hope to help

Giuseppe