OSPF or static routing over MPLS

bblack · ‎12-07-2006

Hello,

Our company will be moving to MPLS network over the next 4 months. Our current network uses EIGRP in a hub-and-spoke configuration, the corporate office as the hub. 9 of the remote sites use VOIP, the other 14 sites are smaller offices without VOIP.

Our intention is to implement OSPF over the MPLS. Consultants have advised against this and suggested static routing instead. The company is expected to have 40 remote offices in 2 years. Other than voice traffic, no data is exchanged between the remote sites. This will change as we turn on common file sharing.

I can provide more info if needed,

Thanks for all your info!

dennylester · ‎12-07-2006

When we went to MPLS we orginally went with static routing. We found that as we added subnets we were constantly waiting on Sprint to add the routing updates to the MPLS network.

When we went to a routing protocol Sprint only offered us BGP (most of our routers don't support it) and refused to setup OSPF, so we ended up running OSPF over a bunch of GRE tunnels.

This has worked well for us and allowed us to have autofailover using DDR and floating routes.

Denny

jackyoung · ‎12-07-2006

In terms of the number of sites, it better to use dynamic routing protocol for easy troubleshooting in future.

You can check what dynamic routing protocols are supporting by the telco. They normally supports BGP. Therefore, I suggest to use BGP instead of OSPF, you can simplified the configuration on the route redistribution. If the telco can support OSPF then it is fine to use OSPF too.

Could you advise the reason to use static route from the consultant ?

Hope this helps.

sachinraja · ‎12-07-2006

Agree with jack. static routes should be really fine to start with, but if there are too many networks at a later part of stage, static routes will not scale.. instead of migrating to dynamic routing at a later part, start off with dynamic routing, if ISP supports them.. In MPLS, everything lies with the ISP. They form an important part in this... One advantage you have with dynamic routing is, in case you remove any of your network, it is automatically propogated.. but if it had been static, you need to be behind the ISP to remove those routes.. I guess itz a tough/rough job to do !!!!

Raj

bblack · ‎12-08-2006

Thanks Jack,

USLEC will support OSPF in their MPLS cloud.

The consultants advise to use static routing because of the ease in trouble-shooting and maintaining the network. they are suggesting to route all traffic into the cloud and let the cloud route the traffic.

I can't buy into this suggestion given the amount of growth our company is experiencing. Besides, their contract is up in 21 days, maybe this is something they are suggesting to extend their contract by offering their services during the transition.

jackyoung · ‎12-08-2006

William, thanks for the info. I can't comment on your consultant's intention to suggest this solution. But static route shouldn't be easy for troubleshoot, it was because the route is statically entered in the ISP side, it means no matter your local LAN is down but the WAN still up, the MPLS cloud will still think the path to your LAN is alive. It may not be an issue if there are only 5 sites, if you will expand to more than 10 sites, it will be a problem in O&M side.

Also agreed w/ others that OSPF is not common service in MPLS network from ISP. However, if the ISP agreed to use it and it is your preference, then it is fine to use it. Otherwise, I could recommend BGP instead.

Hope this helps.

etapper · ‎12-08-2006

Hi,

Is it your MPLS network or is it an "ISP" network? If it is an ISP MPLS network it depends on what the ISP can offer (also with respect to QoS through !!)

The best thing is to use a dynamic routing protocol if possible (EIGRP should work fine as well ;)

(Within the next 4-5 months we are replacing our base ATM network with a MPLS network covering 12 sites(growing). We will run OSPF as IGP in the MPLS network, use OSPF as routing protocol for the office network internally and BGP towards the central corporate core office network. And no ISP's :)

E.T.

mark.edwards · ‎12-08-2006

Hi, MPLS service providers don't like offering OSFP as a PE to CE protocol as it is more resource intensive on the PE than other options such as Static BGP or even RIP (which makes it much less scalable). As other people have already suggested, find what protocols your service provider will support and use whatever suites your needs!