[56808] in North American Network Operators' Group
RE: Controlling outbound traffic in a multihomed BGP environment
daemon@ATHENA.MIT.EDU (Ejay Hire)
Mon Mar 17 11:39:50 2003
Date: Mon, 17 Mar 2003 10:39:11 -0600
From: "Ejay Hire" <ejay.hire@isdn.net>
To: "Daniel Abbey" <dabbey@edeltacom.net>, <nanog@merit.edu>
Cc: <cisco-digest@groupstudy.com>,
<isp-outsourcing@isp-outsourcing.com>
Errors-To: owner-nanog-outgoing@merit.edu
Routing based on source address is called "Policy Routing". IF you are =
on a cisco box, create an extended access-list specifying the source =
Ip's, and then match that access list in a route map to set the next =
hop. Apply the route map on ports facing that customer, building a =
chain from edge (facing the customer) to border (facing the internet.
Good Luck,
Ejay
-----Original Message-----
From: Daniel Abbey [mailto:dabbey@edeltacom.net]
Sent: Monday, March 17, 2003 10:20 AM
To: nanog@merit.edu
Cc: cisco-digest@groupstudy.com; isp-outsourcing@isp-outsourcing.com
Subject: FW: Controlling outbound traffic in a multihomed BGP
environment
How can you control outbound traffic from a single subnet - meaning =
forcing
all its outbound traffic out a single bgp edge router in a multihomed
environment.
Here is the scenario:
1. Inbound traffic is engineered using prepends - meaning to force =
inbound
traffic through a particular router, we are using prepends to make one =
path
seem better than the other on the outside.
2. Local preferences are set to control general outbound traffic to =
specific
ISPs - those that are one or two hops away.
3. Now, I have a customer whose traffic I'll prefer to force out a =
single
bgp edge router - all his traffic, no specific ones. The IGP is OSPF, =
and
there are several different distribution routers between the access IGP
router and the core/edge bgp routers.
