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BGP Design / Customer Internet Access with CPE

_networker_
Level 1
Level 1

Hello,

i'm interested in a good design / best practice regarding  the connection of a multihomed Internet Customer with an own public AS (AS1 and Router R) who expects to receive the full BGP Routing Table in the following topology towards a separate Customer Premises Equipment Router, which is connected to an Access Router of the ISP with AS2. That AR is logically connected to two Central Router-Reflectors of  AS2

AS1    ASx     AS2      AS2

R ---- CPE ---- AR ---- RR1

                   \--- RR2   

Should the CPE Router be part of the AS2? In that case, the IGP of  AS2 must be extended to the customer Location where the CPE is located,  which is in my opinion not a good option

  1. Should the CPE Router be part of the AS2? In that case, the IGP of   AS2 must be extended to the customer Location where the CPE is located,   which is in my opinion not a good option
  2. Is it possible to configure the CPE Router to be part of a private "transit-AS"?

Are there other, probably better solutions?

4 Replies 4

shajakhan85
Level 1
Level 1

Hi,

Yes. It's possible to confiure the CPE router as a private transit-AS. This is better option i feel.

Okay, what would be the detailed configuration?

For example the CPE will be configured with AS65000, which AS-PATH would be visible on Routers in AS2?

1 65000?

Is it possible to remove the private AS towards the upstream providers of AS2 with the command "remove-private as"?

Would it be possible, that the Router R also removes the private AS towards other routers in AS1?

Hello,

would it be possible to configure the CPE under AS2 (router bgp 2), but configure "local-as 65xxx" towards the AR?

The advantage would be, that there would be an ebgp Session between the CPE and the AR, and we could use "next-hop-self" on the AR and therefore we can avoid to extended the IGP to the customer location!?

_networker_
Level 1
Level 1

Hello,

referring to the original posting:

Would it be a good design, if the CPE would be part of AS2 (as logically Route-Reflector Client of RR1 and RR2) and the router would be running OSPF as IGP, but the Access-Router AR would be configured as OSPF border Router, so that the CPE would be configured under an extra OSPF Area which is separated from the OSPF Backbone Area 0.?

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