Need help-BGP routing issue

[Joe Lee]

Hello Everyone,

I have a client that they are using MPLS with ISP att via eBGP, and it is configured default-originate in BGP on the router in their primary data center. Their data center will be moved to another location, and the new router in the new locaiton will be configured default-originate in BGP routing. Question is...Does the ISP need to re-configure from their end? Please advise.

Regards,

Joe     

[Reza Sharifi]

Hi,

If the client is connecting to the same router on the ISP side then there is no change on the ISP's router, but if your client is connecting to a different router then the ISP needs to move the config from the old location to the new locations also.

The client need to coordinate this move with the ISP so there is minimum down time.

HTH

[Joe Lee]

Hi Reza,

It is not the same router in the ISP side. Any idea what change they need to make on their router?

Regards,

Joe

[Joe Lee]

Hi Reza,

I just learned from the Cisco, it says,

When BGP is used as the PE-CE protocol, no additional configuration on PE1 or PE2 is needed to

propagate the default to other PEs within the MPLS cloud. A BGP-learned default is automatically

advertised to all the other BGP neighbors unless explicitly filtered.

Can you please explain?

Regards,

Joe

[Reza Sharifi]

Hi Joe,

If it is not the same route on the ISP side and since your client is peering EBGP with ISP, then the ISP needs configure the router in the new location to peer with your client's new router, if not without EBGP peering the clients routes will not propagate to the ISP's cloud.

HTH

[Joe Lee]

Hi Reza,

Sorry, I didn't make it clear. Yes, ISP will definitely need to configure the peering. My question is...I will remove the " default-originate" form the old router and configure it on the new router in the new location. Does ISP need to re-config due to the change on "default-originate"? Please advise.

Regards,

Joe

[Abzal]

Hi,

I'm assuming default route will be advertised to iBGP neighbor on the new router then ISP does not need to do reconfig. You have to make sure that the new router actually has a default route to advertise.

ISP will need to configure peering with new router as Reza said.

Hope it will help.

Best regards,
Abzal

[Giuseppe Larosa]

Hello Joe,

no additional changes are needed on the MPLS SP side just the eBGP session with the new CE node.

The change in advertising the default route from the CE1 side to CEnew side will be automatically accepted on PE side and it will be propagated to all other PE nodes in address-family vpnv4 in MP BGP.

Things would be different if the default route was originated on PE side.

Hope to help

Giuseppe

[Joe Lee]

Hello Giuseppe,

I verified with our ISP, there is no additional changes for them to do. I have one last questiion, how can I configure the network 0.0.0.0 for the default originate over the BGP routing?

Regards,

Joe