09-19-2010 08:28 AM - edited 03-04-2019 09:49 AM
My network is dual-homed to different providers, but one of the provider links is constantly running close to max bandwidth during peak working hours. Prior to upgrading bandwidth or making other changes, I would like to use local-pref to push a specific subnet to the under-utilized link. Can anyone provide examples of how this is typically done?
09-19-2010 09:14 AM
Here is a link with examples of how local preference is deployed
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800c95bb.shtml#localpref
HTH
Reza
09-19-2010 09:18 AM
Hi,
you can use:
router bgp xxx
neighbor your_nei route-map change_locpref in
route-map change_locpref permit 10
match ip address prefix-list to_move
set local-preference 50
route-map change_locpref permit 20
ip prefix-list to_move seq 5 permit a.b.c.d/length
Where your_nei is the neighbor connected through the overloaded line.
Of course you can use
match as-path ...
instead of
match ip address ...
if more comfortable for you.
HTH,
Milan
09-27-2010 06:54 AM
Let me clarify my question a little more...the subnet I'd like to direct to our second Internet provider is really just one address that all of our guest wireless traffic is NAT'd to. So, instead of a /24 that I want to only go to that specific provider, it's a /32. Would I still be able to use the same approach? I don't think that the provider would accept the /32 would they?
09-27-2010 08:27 AM
Hi,
ah, so far I thought you had asked for an outgoing traffic modification.
As it has no sense to use local preference to modify incoming traffic behaviour.
You can use other tools to change the way your neighbors prefer the subnets advertised from your AS:
As-prepending, communities agreed with your neighbor, etc.
But definitely advertising /32 is not the best practice.
It will be probably either dropped or summarized within the Internet very soon.
BR,
Milan
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