Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements
Webcast-Catalyst9k
New Member

Outbound traffic engineering using BGP.

We have dual-homed BGP, with AT&T and Sprint, with links from ISP terminating on different

chassis.

We also have different network blocks from each ISP, let's say block A, B, & C from ATT

and block X, Y, & Z from Sprint.

What we like to do, is if traffic is sourced from A/B/C, we always want to send it out to

ATT and if traffic is sourced from X/Y/Z, it is always sent to Sprint - as long as links

to ISP is up.

How can I do this using BGP?

5 REPLIES
Hall of Fame Super Silver

Re: Outbound traffic engineering using BGP.

Hello Paresh,

BGP has a rich set of tools but all of them are confined in the "destination based" dynamic routing world.

For routing based on a source address the right tool is PBR with or without NAT.

(NAT can be done before/more inside for different reasons security performance ...)

Hope to help

Giuseppe

Bronze

Re: Outbound traffic engineering using BGP.

Hello,

This seems like a fairly general question, perhaps you can provide additional details. Are you looking to send AT+T networks over Sprint in the event of an AT+T outage. Do you have a public AS number? Is each block Provider Assigned or Provider Independent?

It definitely sounds like route-maps are the way to go, although I'm not sure I understand completely what you're trying to accomplish.

This is a basic overview from Cisco's site, http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a008009456d.shtml

however a different example is found in Routing TCP/IP Vol2 Page374.

Please provide additional info and review the documents to see if they are of any assistance.

JB

Hall of Fame Super Silver

Re: Outbound traffic engineering using BGP.

Hello James,

a good document for enteprise multihoming with NAT and BGP is:

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a0080091c8a.shtml#wp30809

Actually, there is a good example in the Jeff Doyle's book where route-maps are used with NAT.

Hope to help

Giuseppe

New Member

Re: Outbound traffic engineering using BGP.

Thanks, Guiseppe!

I will take a look at link and Doyle.

Paresh.

New Member

Re: Outbound traffic engineering using BGP.

Hello JB,

Answer to all three questions above are "yes".

What I am trying to do is influence outbound traffic to take specific ISP link as long as it it available. I know this can be done using PBR. But, I am trying to do this within BGP.

I will look at TCP/IP Vol-2.

Thanks,

Paresh.

607
Views
0
Helpful
5
Replies
CreatePlease to create content