[c-nsp] Route Aggregation and Deaggregation

[Tony]

Hi Jen,

You can do that. All of your traffic for the /24 will come to you via ISP3 as this is a more specific match than the /19 it is part of. If you drop your link to ISP3, then your /24 traffic will then be received via one of the /19's you advertise to ISP1 & ISP2.

If this is your intention, then go for it. No need to also advertise the /24 to ISP1 & ISP2 unless you want some of the traffic for that /24 to come inbound on those links.



regards,
Tony.




>________________________________
> From: Jennifer Pruett <jennypruett88 at gmail.com>
>To: cisco-nsp at puck.nether.net 
>Sent: Thursday, 19 July 2012 3:28 PM
>Subject: [c-nsp] Route Aggregation and Deaggregation
> 
>Good day!
>
>Question for any BGP guru's; we have a couple of ASR routers as our border
>routers which are advertising a few /19's. The question is not directly
>related to the ASR hardware, but the
>process and best practice of aggregating PI assigned space. If we advertise
>our /19's via ISP1 and ISP2 and then introduce ISP3 and only advertise a
>/24 from one
>of the /19's, do we have to deaggregate the /19 that the /24 was pulled out
>of to accommodate the /24 that we would advertise via ISP3? What are the
>ramifications of
>such actions?
>
>Thanks for your time
>Jen
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