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Cat 4500 GRE Tunnel performances

helenio
Level 1
Level 1

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 ?

8 Replies 8

Hitesh Vinzoda
Level 4
Level 4

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
Hall of Fame
Hall of Fame

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

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 ?

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

Where can I fing Tunnel performances based on RTR Model ?

Hello Helenio,

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

Hope to help

Giuseppe

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

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

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