BGP vs GRE on MPLS L3

[wilson.jr]

Hi,

I’m planning to run OSPF on MPLS L3 connection between offices in Central and South America. I have to option; work with ISP on implementing BGP and redistribute BGP into OSPF or run GRE tunnel between offices and then OSPF on top of it. Reason behind GRE is because it is can be complicated to work with multiple ISP. Can someone let me know what pros and cons of each solution are?

Thank you

[vmiller · Accepted solution]

Are you getting MPLS services from a carrier?

If so, they should be doing all the heavy lifting once you agree to terms, your sites should be simple ce routers.

[wilson.jr]

Yes I’m getting services from carriers, but anyway I would like to know what are pros and cons of each solution

[vmiller · Accepted solution]

Well, my own two cents worth.

I'd look real hard at the MPLS solution. It fences you out of the backbone management business.

It does require some effort to work out the contractual details, (i.e. qos, maintenance windows onthe mpls backbone etc)

It keeps your local configs fairly simple and gives you one throat to choke if the WAN has issues.

on the CON side, you do not have visibility into the cloud, which makes some performance issues a real headache at times.

I have never been a big GRE fan, (too static). I'll let others weigh in on that.

[Kishore Chennupati · Accepted solution]

Hi,

I am with vmiller. It's always good to put the load on MPLS for some extra money. Also, you need to consider the number of sites you have and think about the scalability as well.

Using dyanamic protocols lowers you admin overhead as you are aware. Having GRE Tunnels becomes a cumbersome task after a while. For a small network , its ok but as your network grows big it becomes a pain. I have worked for a client with like 200 GRE Tunnels and its not easy when things fall over especially with IP re addressing etc.

Please have a chat with your ISP account manager to see what costs are involved to get an IPVPN with QoS etc.

HTH,

Regards

Kishore

Please rate if helpful

[Mohamed Sobair · Accepted solution]

Hi,

1- There would be no impacts if you run BGP with the service Provider and redistribute it into OSPF, of course with the proper route filtering in place.

2- However, It would be challenging if you need Encryption (IPsec between your sides) and your company requires Voice and Video Or Multicast applications.

If (2) is correct, then I would recommend running GRE and OSPF in top of your GRE tunnels, with this Scenario , you have no problems running IPsec and Multicast applications over the connection.

Since you have too much sites connected to the Service Provider, a Proper pre-plan has to be taken into place along with all consideration before the implementation phase.

HTH

Mohamed

[wilson.jr]

(2) is correct. I will have some sites that required encryption because of privacy issue and need VoIP and multicast on all links as well. Why you have mentioned that it will be challenging to run VoIP and multicast over MPLS?

Thank you

[vmiller · Accepted solution]

VoIP should be no problem over MPLS.

You just need to make sure that you have a solid understanding of how the carrier will treat your marked traffic.

generally the carriers offer various service levels of managing marked traffic.

I can't think of an issue with multi cast. but thats a discussion to have with the provider.

[Mohamed Sobair · Accepted solution]

I actually shouldnt say challenging, its Actually impossible to run Video Application based on Multicast over Normal IPsec tunnel.

As I said, since you confirmed (2) is correct, then I recommend running GRE Over IPsec to transport your Video Multicast application as well.

HTH

Mohamed