Any takers? On Tue, Jun 8, 2010 at 3:42 PM, Joshua Yost <[email protected]> wrote:
> I asked something similarly weird earlier, then gave up on it, but now I > have been testing it and am just confused > > Here's situation 1: > > R1------AREA0-----R2----------AREA111---------R3----------MPLS--------------R4---------------AREA > 222------------R5 > > > Now, without a virtual link through area 111, area 0 and area 111 are > isolated, and only know OSPF information from each other. This makes sense. > Now if I extend a virtual link through area 111 to the PE, I have > reachability to the Area 222. > > To break this down, and all sham link configurations set aside*, if I have > area 0 at any site in my MPLS VPN topology (as the customer), I must extend > it to the MPLS with a virtual link? Is that right? > > * > > Now, on to situation 2: > > > *R1*------AREA0-----R2----------AREA111---------R3----------MPLS--------------R4---------------AREA > 222------------R5----------AREA 222-----*----R1* > > Note this is a circle with R1 being an ABR for areas 0 and 222. > > Loopbacks are all R.R.R.R > > R1s loopback is in area 222 > R2 L0 in area 0 > R5 L0 in Area 222 > > So you can probably see where this is going, R5 - R1 would be my good ol > "Backdoor link" > > Right now with no manipulation, R2 gets to R5's L0 via R1 and the backdoor > link. In fact regardless of manipulation this is the case. > > Now, I want all traffic from R2 to area 222 to go over MPLS. > > So I configured the virtual link through 111 as described in the previous > example, then I configured an area 0 sham link over MPLS. Then magically, I > can route however I want over MPLS by playing with cost. Specifically, if I > want R2 to get to R5's loopback via MPLS, I just cost up the link between R1 > and R2 on R2. None of this works without the sham link, but I thought we > needed area 0 on both sides of the sham link for this to work? Is there an > exception? The sham link is acting kinda like a virtual link but not really. > HELP > > > > > > > > > >
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