attached you will find a simple topology for which I have a few questions. We are running OSPF in our network and recently we have converted to MPLS with our provider. The routing protocol between our CE our router / CPE (providers router) and the PEs is still OSPF with areas as shown in the diagram. All major traffic engineering is done in the providers cloud.
Because the provider has enabled max-lsa on PE-2 when the ISDN connection came up, due to the LSAs sent by the branch router towards PE-2 the OSPF adjacency (PE-s / CPE) came down. In order to overcome this problem, I thought of configuring "ip ospf database-filter all out" on the dialer on CE, so that it wouldn send its database to the branch router, which would in turn send it towards PE-2. This seems to work fine. When the ISDN line comes up, the branch LSA database does not change. The problem is that the branch router sends its database to CE, which as I understand sends it to PE-1 (PE-1 is also configured with max-lsa, I suspect with a higher value than that of PE-2). This is not a major issue when only one branch uses its ISDN backup (the size of the LSA database increments by a value of ~= 700), but what if more branches use their ISDN backup simultaneously??? Then the adjacency between CE (core router) and PE-1 would come down!!!!
My first idea to overcome this, was to also set "database filter all out" on the branches dialer. I read in the following link "http://fengnet.com/book/Cisco.IOS.Cookbook.2nd/I_0596527225_CHP_8_SECT_3.html" that:
The "database-filter all out" does not block OSPF Hello packets, so the routers will still form full and normal adjacencies. Also, it only blocks the sending of LSA packets. The router will receive routes normally.
So I thought that the routing will still work. After configuring the "database-filter all out" I lose connectivity with the branch!!!! Why is that? Shouldn routes be received by both ends?
Thanks in advance,