sham link

yren

HI I am learning sham link on Junos and found 2 problems:

I have CE1 connects to both PE1 and PE2, while CE2 connects PE3

1: if the backdoor link between CEs is 1GE, which means ospf cost is 1 (backdoor link is in ospf area 0), and this is already the minimum that remote-sham-link can support. So as the result, CE1 and CE2 will learn CE routes from both VPN and backdoor and will be doing load-balancing. If CEs are not configurable to increase the cost, is there any solution to prevent this happening?
2: I expected to see the routes learned from CE being distributed back to the same CE, but this did not happen as long as there is no sham link config. But, as soon as sham link was configured in vrf proto ospf, then CE1 got its own routes back from its connected PEs, and same as CE2. I tried to set site of origin and reject community origin before exporting bgp to ospf, but it just did not work.
I suppose sham-link made the core like an ospf area 0 and vpn bgp routes behavior as intra-area routes so the intra-area lsp could not be filtered by any means??? The CE routes are type3 and 5. This is not a huge problem since these routes are not active on CEs due to higher preference. But is there any way to do filtering?

Please advice! Thanks.

hoogen82

1. I understand why CE's may not be configured... but its certainly hard to figure out..if you don't have access on CE's
2. I don't quite understand it... I am assuming Ce1 routes are advertised back to it by Pe1.. ? there was a solution in JNCIE book to filter these..