[c-nsp] BGP advertisements more specific than IGP

[James Urwiller]

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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