[c-nsp] bgp maximum-paths

[Chris Gotstein]

It's inbound i'm mostly concerned with.  I'm taking full routes from
both providers.  Paths to both a relatively equal, so the path with the
lowest ID is winning, causing it to be overloaded.

---- ---- ---- ----
Chris Gotstein, Sr Network Engineer, UP Logon/Computer Connection UP
http://uplogon.com | +1 906 774 4847 | chris at uplogon.com

On 4/14/2010 4:43 PM, MrPaul wrote:
> Are you wanting to load balance inbound, outbound, or both?
> 
> Without knowing all the details the cleanest solution would be to split
> your address space in half.  Then send one half to provider A and the
> other half to provider B.  Also send the entire network block to both
> provider A & B for backup purposes.  The only issue here is you need to
> hope that you have enough address space to support this.  That way under
> normal circumstances 1/2 your IP space will come in provider A while the
> other half will come provider B.
> 
> For outbound load balancing you'll probably need to take full routes and
> then do something like prefer odd addresses out provider A and even out
> provider B.  You may find that taking full routes will balance enough. 
> Typical customers don't bother load balancing outbound traffic as there
> isn't much.
> 
> Paul
> 
> On Wed, Apr 14, 2010 at 4:26 PM, Chris Gotstein <chris at uplogon.com
> <mailto:chris at uplogon.com>> wrote:
> 
>     Does this seem like a valid way to load balance?
> 
>     http://ccnalab.net/bgp-routing/bgp-load-sharing-2-isp/
> 
>     ---- ---- ---- ----
>     Chris Gotstein, Sr Network Engineer, UP Logon/Computer Connection UP
>     http://uplogon.com | +1 906 774 4847 | chris at uplogon.com
>     <mailto:chris at uplogon.com>
> 
>     On 4/14/2010 4:23 PM, MrPaul wrote:
>     > On Wed, Apr 14, 2010 at 3:03 PM, Chris Gotstein <chris at uplogon.com
>     <mailto:chris at uplogon.com>
>     > <mailto:chris at uplogon.com <mailto:chris at uplogon.com>>> wrote:
>     >
>     >     We are a multi-homed ISP with connections to 2 different
>     providers (AS
>     >     Numbers)  Does the bgp maximum-paths 2 command have any effect
>     on load
>     >     balancing between the 2 connections since they are different
>     AS's or
>     >     does that command only work when you have multiple paths to
>     the same AS?
>     >
>     >
>     > Taken from
>     >
>     http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00800945bf.shtml
>     >
>     > By default, BGP chooses one best path among the possible equal-cost
>     > paths that are learned from one AS. However, you can change the
>     maximum
>     > number of parallel equal-cost paths that are allowed. In order to make
>     > this change, include the maximum-paths paths  command under the BGP
>     > configuration. Use a number between 1 and 6 for the paths  argument.
>     >
>     > That feature is only of use if you are dual-homed to the same AS.
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