MPLS w/ OSPF: no area 0, is it possible?

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Jun 17th, 2010
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Have a situation where we're running L3 MPLS to one of our remote sites.  I'm in the process of re-organizing the OSPF network such that it aligns a bit better with the design guide/recommendations.


Currently there's the core routers (area 0), then the distribution (ABR for multiple areas).  This will be changed so that the distribution no longer functions as ABR's but rather are dedictated to a single area. The problem is, the current MPLS/OSPF setup uses area 0 on one (CE-PE) side, and obviously my new design does not allow for area 0 off the distribution block where it's currently connected.  I'd rather not connect this remote site to the core either...


I'd like to know if it's possible to run the MPLS/OSPF setup in one single area (as an extension of the distribution blocks area) rather than having area 0 play a part...  In other words, rather than having the CE-PE on one side setup in area 0, both CE-PE sides running in, area 10 for example... is this possible?  What are the risks if any?


Some answers I've seen seem to indicate yes, meanwhile all the cisco docs use examples with area 0 and don't necessarily say no...


Thanks in advance.

Ben

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aarongwood Mon, 08/09/2010 - 19:47
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I've got the same question. Have you ever found an answer? I tried it myself and it didn't work but I'm only hypothesizing that it was because there was no area 0, I'm not 100% sure...

Giuseppe Larosa Tue, 08/10/2010 - 04:14
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Hello Aaron,


it is possible to connect PE-CE in a non zero area, in order to see routes of remote sites as O IA interarea instead of O E2 (external routes) the same OSPF process-id has to be used on all PE routers.



see

http://www.cisco.com/en/US/docs/ios/mpls/configuration/guide/mp_cfg_layer3_vpn_ps6441_TSD_Products_Configuration_Guide_Chapter.html#wp1062224


Hope to help

Giuseppe

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