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BGP allowas-in / Isolated PoP's

UTVi-NetAdmin
Level 1
Level 1

Hi,

Consider 3 PoP's with eBGP peering to upstream providers.

Also, low bandwidth connections directly between each PoP.

We have the following options:

1. Statically route each PoP's address space across internet.

2. Use the 'allowas' feature to accept announcements from each of our other PoP's.

IS there any merit in creating a 'mesh' of tunnels between each PoP in order to distribute inter-PoP traffic or even dynamic routing info.

Any thoughts/scenarios appreciated!

Thsnks.

3 Replies 3

Harold Ritter
Cisco Employee
Cisco Employee

The only reason for iBGP in this scenario would be to share a unique routing policy among the 3 POPs.

Why would you use tunnels if you already have links between the POPs.

Hope this helps,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

I guess the reasoning behind the tunnel is to make use of faster internet connection, rather than the slower internal connections.

I might prefer the allow-as in, while still having iBGP connections, so that traffic might be able to failove to the internal link in the event of failure

This would be done naturally without the use of tunnels, wouldn't it. The eBGP route learnt via the SP would be preferred over the iBGP route learnt via the internal link whether you use a tunnel or not.

Hope this helps,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
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