Yeah, I got'cha. MPLS between the two BGP routers solves this, too. Without the L2 or MPLS, there'd be a routing loop. I generally set local pref so that once traffic reaches an edge router, it goes out that way, even if it's not the shortest AS path. Unless they're serving up content, its the inbound direction that really matters.


Jesse DuPont

Network Architect
email: jesse.dup...@celeritycorp.net
Celerity Networks LLC

Celerity Broadband LLC
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On 5/3/16 10:37 AM, Mike Hammett wrote:
Correct, but it's a bit cleaner if they are.

The two different routers will be advertising default routes. Traffic will go to the nearest Provider Edge (PE) router. If the other PE router has the better route, having them connected via layer 2 better moves the traffic to the other PE.

Having iBGP running on all routers between the two PEs makes it even better, but at the cost of making sure all of the routers between are capable of it.



From: "Jesse DuPont" <jesse.dup...@celeritycorp.net>
To: af@afmug.com
Sent: Tuesday, May 3, 2016 11:26:23 AM
Subject: Re: [AFMUG] BGP and OSPF

The two BGP routers do not need to be on the same L2 network for the iBGP connection.


Jesse DuPont

Network Architect
email: jesse.dup...@celeritycorp.net
Celerity Networks LLC

Celerity Broadband LLC
Like us! facebook.com/celeritynetworksllc

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On 5/3/16 10:25 AM, Mike Hammett wrote:
A BGP speaker would be a router speaking BGP. In this case, most likely your routers at the edge of your network that connect to your providers.

Are the routers that are between your two BGP routers capable of running BGP, resource wise?

Can you do a VPLS tunnel between your two BGP routers? If not, what about a VLAN?


From: "That One Guy /sarcasm" <thatoneguyst...@gmail.com>
To: af@afmug.com
Sent: Tuesday, May 3, 2016 11:13:36 AM
Subject: Re: [AFMUG] BGP and OSPF

Mike, i said helmet, explain it to me like you would a 10 year old, then dumb it down to my level from there.

I dont know what a bgp speaker is

On Tue, May 3, 2016 at 11:10 AM, Mike Hammett <af...@ics-il.net> wrote:
Your OSPF network will just use default routes to get to your BGP speakers.

Your BGP speakers with full routes will choose the best path. Your BGP speakers should be connected together, via direct connection, layer 2 tunnel (VPLS) or via intermediary iBGP speakers. Those iBGP speakers in the middle of your network will route the correct way, based on BGP.


From: "That One Guy /sarcasm" <thatoneguyst...@gmail.com>
To: af@afmug.com
Sent: Tuesday, May 3, 2016 10:41:52 AM
Subject: [AFMUG] BGP and OSPF

We currently have a /22 with 2 /24 statically routed in each of our providers. We are moving to BGP.

What Im still unclear on is how my OSPF network is going to decide on the best path for data to flow externally

can somebody give me the helmet version of how this is accomplished

--
If you only see yourself as part of the team but you don't see your team as part of yourself you have already failed as part of the team.




--
If you only see yourself as part of the team but you don't see your team as part of yourself you have already failed as part of the team.




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