[c-nsp] BGP advertisements more specific than IGP

[Mack McBride]

Most providers have a set of communities to set local pref and
Re-advertisement to peers that can be used to influence inbound
Traffic.

The short answer is there is not a 'good' way to influence inbound
Traffic.  Communities are your best bet.

-----Original Message-----
From: James Urwiller [mailto:jurwiller at americanbb.com] 
Sent: Friday, March 01, 2013 10:27 AM
To: Mack McBride; cisco-nsp at puck.nether.net
Subject: Re: BGP advertisements more specific than IGP

Community strings don't effect inbound traffic, right?
Is there really no good way to influence inbound traffic?

James Urwiller
Network Operations Manager
CCNA 11567125
American Broadband
402-426-6257 - Office
402-278-1875 - Cell
402-426-6273 - Fax




jurwiller at americanbb.com





On 3/1/13 11:25 AM, "Mack McBride" <mack.mcbride at viawest.com> wrote:

>You can use conditional advertisement to do what you are wanting to do.
>But as Randy mentioned you should really use communities with your 
>upstreams to influence traffic.
>If communities don't work then consider conditional advertisement.
>http://www.cisco.com/en/US/docs/ios/12_0/np1/configuration/guide/1cbgp.
>htm
>l#wp9071
>If you advertise your deaggregates you should still advertise your 
>aggregate block.
>That allows those of us who don't care about your traffic engineering 
>desires  but do care about the routing table size to drop your 
>deaggregates.
>At some point a lot of providers are going to be dropping deaggregates.
>
>LR Mack McBride
>Network Architect
>
>-----Original Message-----
>From: cisco-nsp-bounces at puck.nether.net 
>[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of James Urwiller
>Sent: Thursday, February 28, 2013 8:12 PM
>To: cisco-nsp at puck.nether.net
>Subject: [c-nsp] BGP advertisements more specific than IGP
>
>I have a BGP multi-homed invironment that I am having problems 
>balancing inbound traffic, besides prepends which don't seem to be 
>helping anymore, I have heard that announcing my networks more 
>specifically could also influence inbound traffic.  My question is, for 
>example... If I have a
>/23 that I am using as a /23 in OSPF, can I announce that in BGP more 
>specifically (2, /24's)  without having to them break it up internally 
>as well?  What I foresee happening is this..
>
>Example:
>BGP:
>Network 192.168.0.0/24
>Network 192.168.1.0/24
>
>OSPF:
>Network 192.168.0.0/23
>
>I would think in this scenario, the IP addresses 192.168.1.0 and
>192.168.0.255 would not have a route in BGP, even though they are valid 
>addresses for use when used as a /23.  Since I would be multi-homed, I 
>would still advertise the network as the aggregate /23 on the circuit I 
>don't want to take as much traffic, so would those IP addresses in this 
>scenario still work, but only through the circuit I advertise as the 
>aggregate??
>
>James Urwiller
>Network Operations Manager
>CCNA 11567125
>American Broadband
>402-426-6257 - Office
>402-278-1875 - Cell
>402-426-6273 - Fax
>jurwiller at americanbb.com<mailto:jurwiller at americanbb.com>
>
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