BGP inquiry

[theboywhocriedwolf]

hi,

for the diagram below:

would it be possible to configure BGP even if i only have one router for each side?

(making the 2 routers neighbor)

thanks

[John Blakley]

It would be easier and more reliable to set up a vpn connection between the two routers and then route over that.

[theboywhocriedwolf]

would it be possible to create BGP for each isp so that they will have local peering?

(pls see diagram)

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

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Posting

If you mean peering between the ISP router and your router, sure, you can set up an eBGP session.  You would also normally want to define an iBGP session between your two routers so both of your routers "know" of the other ISP routes.  This way, if an outbound packet arrives on one of your routers, but the other ISP has a shorter AS path, your router would send the packet to your other router.  (Oh, when you do this, you also want to insure your two BGP routers don't allow transit traffic between the two ISPs.  [Also, normally, your ISP policies would preclude this too.])

[theboywhocriedwolf]

thanks for your reply sir,

so how would it be possible for the two router? will i connect the two router with a ethernet cable? what will be the form of my network diagram if thats the case?

[ciantwohig]

As there are only two sites, setting up a IP Sec VPN tunnel would be the best approach.  

http://www.cisco.com/en/US/docs/ios/12_3t/12_3t14/feature/guide/gtIPSctm.html

https://supportforums.cisco.com/document/13576/how-configure-gre-tunnel

[paul driver]

Hello

Yes it is very possible

As other have suggested - You can also use IPsec/Gre or VTI vpn and run bgp over that

res

Paul

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of   the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

As the other posters have noted, yes it should be possible (for either iBGP or eBGP).

However, if you directly peer your branch and DC BGP routers, each BGP router can "know" what the other BGP router knows, but the in-between Internet routers may not.  I.e. packet delivery/forwarding may then fail.

Also as the other posters have noted, you can create a tunnel between the two BGP routers, then you would be able to pass traffic between them, but be aware tunnels have additional performance considerations.

Also, if you do tunnel between the two routers, you might also prefer to use a IGP rather than BGP between your two routers.