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routing bgp multipath

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#1 Thomas Pitchford

Thomas Pitchford
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Posted 04 June 2018 - 10:06 AM

Hello,

 

I'm having trouble getting my routing correct. I have two separate ISPs configured to work with BGP routing between them. Both ISPs advertise the same address space. The NG sees only one ISP, but there are two. Because the NGs can't handle full routing tables from two ISPs, I had to setup two routers to handle the BGP sessions.

 

Router 1= 1.1.1.2

Router 2 = 1.1.1.3

VRRP = 1.1.1.1

 

Currently I'm relying on the VRRP address of the routers, but I've never liked this solution (its there for other services we offer). We're only able to use one ISP for outbound traffic at a time with this topology.

 

As luck would have it, we recently experienced an issue where ISP 2 was the VRRP master and it went down causing all outbound traffic to stop. ISP 1 was up, but VRRP was never returned to ISP 1. We have other ISPs outside of our BGP, but because the NG saw ISP 1 was up, it never sent traffic to our other ISPs. It was honestly the perfect storm.

 

My preference is to have traffic go out both ISPs as evenly as possible. I've tried setting up two route statements (with different metrics), but it would never route traffic to our secondary router. I've looked at configuring multipath routing, but the following page says that if one part goes down then the entire multipath route is considered down. And I do need the ability to check the status of the next hop on a given path. https://campus.barra...ipath-routing/ 

 

Has anyone experienced anything like this and how have you gotten around it? My goal is to send 50% of my traffic to 1.1.1.2 and the other 50% to 1.1.1.3. If that's not possible, then send everything to 1.1.1.2 until the next hop is down, then send to 1.1.1.3.

 

Thank you.



#2 Michael Zoller

Michael Zoller
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Posted 05 June 2018 - 09:45 AM

I think this article describes the setup you want to create: https://campus.barra...m/doc/73719017/

 

The link balancing is configured in the connection object of the access rule:

https://campus.barra...m/doc/73719279/

 

https://campus.barra...m/doc/73719280/