RE: controlling outgoing traffic among dual links BGP

Thanks a lot team,

We always reach to point to use the link controller to control the outbound
traffic for unequal load balancing, is that hard to implement the solution
using the routing protocol!

On many cases one of the link will be filled up and we shall have complete
downtime on the branch.

From: marc abel [mailto:marcabel_at_gmail.com]
Sent: Thursday, August 15, 2013 4:33 PM
To: John Haddad
Cc: Cisco certification
Subject: Re: controlling outgoing traffic among dual links BGP

You have two separate issues here. Outbound and Inbound.

For outbound you have a couple options. Just getting a full feed from two
ISPs will allow you to utilize both links but doesn't really do load
balancing. You can use PFR (OER) to do more intelligent outbound decision
making. Another option is to use the bgp dmz-bw
http://www.cisco.com/en/US/docs/ios/iproute_bgp/configuration/guide/irg_link
_band.pdf

Inbound you run into different problems. If you have equal cost links to 1
ISP you can possibly get them to load balance, but if different ISPs you are
stuck. You can subnet your IP range and advertise different prefixes to your
providers and then try to manually balance your traffic by assigning public
IPs to different ISPs. For example your main NAT address come in through
provider A, but your webservers come in through provider B. Keep in mind
most ISPs wont accept anything less than /24. You would use AS path
prepending to make the secondary link less preferred for each traffic class.
There is also some things you can do with PFR (OER) inbound now where it
automatically samples traffic and does dynamic as path prepending, but I
have not personally used this.

One of my biggest disappointments in studying for the CCDP was that none of
this was discussed in any of the literature I read. Seems to be one of the
most common design questions I run across and Cisco didn't cover it at all
in their professional level design test.

Hope that helps,

Marc

On Thu, Aug 15, 2013 at 2:14 AM, John Haddad <loserboy3000_at_hotmail.com>
wrote:

Dear team,

What is the best approach to activate dual links load sharing or load
balancing using routing protocol over the internet ?

If we have two ISP links coming to two routers and the ISP is using BGP to
connect with us, what is the best approach to implement the following:

1- if we have equal links from ISP
2- if we have unequal links

How can we control the outgoing traffic to have the ratio for example 1:3 in
case of unequal links.

Thanks a lot

The setup is the following:

Edge switch 2960 core switch 6509 ASA router

Blogs and organic groups at http://www.ccie.net
Received on Thu Aug 15 2013 - 16:43:56 ART