gurinder
join:2007-11-19
122001
| How to Loadshare between a E1 LInka nd Ebgp(MPLS) Link
LINK Diagram |
As per the diagram we have one E1 link from location A to Location B and one MPLS link from Location A to Location B. We want to load share and redundancy thru these both links for Location B. The links are terminating on diffrent routers at location B. And at location A and B we are running EBGP with service provider's COE router.
PLease any body can help us. We are not able to locate the solution for this type of setup. |
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spivver
join:2007-07-15
Manchester, NH | »www.cisco.com/warp/public/459/40.html |
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aryoba
Premium,MVM
join:2002-08-22
| reply to gurinder
The previous link provided was one way of doing so, assuming there is a BGP network in place. I'm not sure if the link is applicable to your network.
On the diagram I only see eBGP between your ISP PE and your CE router. How about between MPLS cloud and Location A? Is there an eBGP peer as well? Same question in regards to E1 between Location A and Location B.
Further detail of your network design will be helpful. |
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gurinder
join:2007-11-19
122001
| Hi Thanks for your reply.
Please find the updated diagram. We are running the EBGP with service provider's COE at both locations . Location A is our main office and Location B is our remote office.
And we will have these two types of different link(MPLS and E1) for load balance and redundancy. |
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aryoba
Premium,MVM
join:2002-08-22
edit:
November 23rd, @12:12PM
| Since you are having BGP network, you might as well run eBGP peer between Location A and Location B via the E1 link.
I would guess that Location A's Router A and Router B are within their own BGP AS domain. Similarly, Location B's Router C and Router D are within their own BGP AS domain.
The MPLS Cloud is a single BGP AS domain. There are two hops away between Location A and Location B from BGP routing path perspective.
With that in mind, you could run eBGP between Location A's Router B and Location B's Router D. The Router A and Router B run iBGP. Similarly the Router C and Router D run iBGP.
Note that by default, there is only a hop away between Location A and Location B via the E1 link. Therefore by default, the E1 link will be preferred path instead of the MPLS Cloud for communication between Location A and Location B.
If you like BGP routing to go across MPLS Cloud as primary and goes over the E1 link only when the MPLS Cloud connection fail, then you need to tune the BGP path selection. One simplest method is to set the AS Path Prepend.
From the IGP perspective, you need to configure your internal routing to dynamically point to the BGP router with fewer AS Path hops. In other word, you have to tune in the BGP-to-IGP redistribution metric to have the IGP "understands" the BGP routing.
Headsup:
Setting up the AS Path Prepend is usually straight forward. However to tune in the BGP-to-IGP redistribution metric to have the IGP "understands" the BGP routing is not. There will be some trial and error to have the correct setup. In other word, you really have to understand the working mechanism of the BGP and your IGP (EIGRP, OSPF, or whatever you use) .....  |
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