Adam! Thanks agian for the prompt response.
The response of my network as mentioned in my last e-mail was as expected. I didn't redistribute between OSPF and BGP, simply created the sham-link between the two PEs (in short extended my area 0 across the provider) so the PE it was extended to was seeing the route as intra-area. Whereas reverse path was inter-area due to the fact that R4 was CE interface was in Area 1. I have tested with redistribution and various scenarios as you have mentioned below and as usual you are right. The only confusion I have now is: Why do we need to redistribute between OSPF and BGP when we can simply create a sham-link and manipulate the type of route? I have a feeling my question is very dumb but then better ask than sorry later :/ Thanks again mate. Regards, Samir Idris. On Tue, Jul 19, 2011 at 12:59 AM, Adam Booth <[email protected]> wrote: > Hi Samir, > > I believe things should be operating as expected. Only non-shamlinks care > about the domainid: > > If it wasn't a shamlink, and the domain ids were different, it would appear > as an E2 route. > If it wasnt a shamlink and the domain ids were the same it should appear as > an inter-area route. > If it was a shamlink and the domain ids were different, it would appear as > an intra-area route. > If it was a shamlink and the domain ids were the same, it would appear as > an intra-area route. > > Cheers, > Adam > > On Mon, Jul 18, 2011 at 8:31 PM, Samir Idris <[email protected]>wrote: > >> Hi Guys, >> >> I am totally confused now. I have the following topology: >> >> R1 --- OSPF (Area 0) ----CE --- OSPF (Area 51) --- R5 ----- MBGP ------ R4 >> ---- OSPF (Area 1) --- CE ---- OSPF (Area 1) ---- R2 >> >> R5 = R4 = PE >> >> From left to right: >> >> I have configuredf a virtual-link from CE to R5. R5 to R4 a sham-link. >> Configuration is as follows: >> >> R5: >> >> router ospf 18 vrf vpn30 >> router-id 30.30.5.5 >> log-adjacency-changes >> area 0 sham-link 30.30.100.5 30.30.100.4 (the loopback interfaces that >> are >> NOT advertised into OSPF but only BGP) >> area 51 virtual-link 30.30.7.7 >> network 30.30.0.130 0.0.0.0 area 51 >> >> R4: >> >> router ospf 9 vrf vpn30 >> router-id 30.30.4.4 >> log-adjacency-changes >> area 0 sham-link 30.30.100.4 30.30.100.5 >> network 30.30.128.130 0.0.0.0 area 1 >> >> Loopback for R1 = 30.30.1.1 >> Loopback for R2 = 30.30.2.2 >> >> Now here is what I think should be happening, since different Process IDs >> on >> both R4 and R5, IOS will treat them as differ domain-id and hence the >> route >> when taken from the remote CEs should be E2 routes where as I see them as >> follows: >> >> R4(config-router)#do sh ip route vrf vpn30 30.30.1.1 >> Routing entry for 30.30.1.1/32 >> Known via "ospf 9", distance 110, metric 22, type *intra area >> * Last update from 30.30.5.5 00:09:40 ago >> Routing Descriptor Blocks: >> * 30.30.5.5 (Default-IP-Routing-Table), from 30.30.1.1, 00:09:40 ago >> Route metric is 22, traffic share count is 1 >> R5(config-router)#do sh ip route vrf vpn30 30.30.2.2 >> Routing entry for 30.30.2.2/32 >> Known via "ospf 18", distance 110, metric 32, type *inter area* >> Last update from 30.30.4.4 00:10:04 ago >> Routing Descriptor Blocks: >> * 30.30.4.4 (Default-IP-Routing-Table), from 30.30.4.4, 00:10:04 ago >> Route metric is 32, traffic share count is 1 >> No matter what I do, if I change the process IDs at both R4 and R5 to be >> similar, the routes remain the same. I have tried using same process ID >> with different domain-id too but to no avail. Can anyone point out my >> mistake here? With different Proccess ID I expect the routes to be E2. >> >> Sorry for bringing this up again. >> >> Regards, >> -- >> Samir Idris >> _______________________________________________ >> For more information regarding industry leading CCIE Lab training, please >> visit www.ipexpert.com >> >> Are you a CCNP or CCIE and looking for a job? Check out >> www.PlatinumPlacement.com <http://www.platinumplacement.com/> >> > > -- Samir Idris _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com
