GRE Performance

Navdeep Mann · ‎11-02-2006

I have a requirement to tunnel 100Mbps through GRE.

Has anyone successfully pushed 100Mbps using a Cisco 7200 through GRE?

We have a total of 4 sites. Each have 100Mbps to the HQ over a service provider network. Customer wants to avoid having to advertise networks to the ISP.

I want to avoid having to recommend Cat6500 or 7600 due to costs.

Running Services:

OSPF,

Routing Policy,

QoS (Shaping/Policing),

Thanks,

Bobby

cdusio · ‎11-02-2006

You should not have an issue running 100 meg over GRE except if the interface you are running it over is 100 meg. GRE is en encapsulation protocol and the only impact is overhead accociated with encapsulation.

network.king · ‎11-02-2006

Hi,

I think running a 100M traffic over the GRE is not recommendable bcos of the overhead it is going to add . And its all going to happen via software , you might also face issues with quite a increase in CPU .

regards

vanesh k

jackyoung · ‎11-02-2006

If it is a Metro Ethetnet, I recommend to use VLAN instead or GRE tunnel. I believe after you enable the 100Mbps GRE tunnel, you may not able to enable other services.

However, is it always 100Mbps throughput or only a snap ? If only a snap, you can estimate/calculate the average rate and test it.

Hope this helps.

Navdeep Mann · ‎11-03-2006

The challenge is our ISP requires us to use them as the next hop as the default from the perspective of a field site.

In a single hub-spoke network this might work. But we have multiple data centers. This would require us to redistribute our routing tables to the ISP.

We don't want to give the ISP our routing infrastructure. Its a huge pain and risk when dealing with routing issues that occur in the ISP network because they always want us to prove to them there is something wrong (which happened just yesterday with another network).

Whenever possible we always use Vlans. But in this case we don't have that option.

Thanks,

Bob.

lgijssel · ‎11-03-2006

Ihave some recent experience on this subject. The main problem with GRE tunneling is that the encapsulation is done via process switching. Even a 7200 will not handle a volume of over 100Meg of data over GRE.

You may perhaps check the design guides for DMVPN which also utilizes GRE. For high end systems a 7600 or better is recommended there as it is able to off-load the GRE process. If there is any option to off-load the GRE process from the main CPU on a 7200 you will likely find it here. Due to the age of the 7200 platform, I am afraid there will be none but you may check anyway.

Regards,

Leo

network.king · ‎11-03-2006

Hi,

If your problem is only with giving the routes and In case if they do mess up , then ask your provider ,if they would be able to give L2MPLS or else go for a MPLS VPN where the SP is not going to touch your routing table and the problem occurence is also less , as they might take proper care of the PE router and Loopback routing.

Hope it helps

regards

vanesh k

jackyoung · ‎11-05-2006

Agreed with Network.King. If it is MPLS, the ISP can knew your route but they won't touch on it. They just carry it in your VRF.

I suggest to consider other option than GRE, it will eat most of the resources.

If L2MPLS, it will looks like a LAN but running on MPLS. It is also a good option, but don't know will your ISP support it.

Hope this helps.

Navdeep Mann · ‎11-05-2006

Yes thanks to everyone. I did talk to the ISP on Friday. They are introducing L2-MPLS services next year. Not sure the time frame but less then 12 months. Its up to my customer at this point to see if they will wait.

Cisco finally got back to me. They mentioned that a 7200 NPE-G2 can push 100Mbps that I need.

Thanks to everyone!

Bobby Mann