Hi The suppression won't fix this behavior but will reduce the number of prefixes ospf needs to carry to roughly 200 -thus enabling you to use a single area 0 I'd recommend not to use multiple areas within the same AS (or confed member-as) as there are mpls features which needs some tweaking when used in inter area environments -it's enough to deal with these in inter-as solutions :)
adam -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Livio Zanol Puppim Sent: Wednesday, October 19, 2011 11:53 AM To: David Prall Cc: [email protected] Subject: Re: [c-nsp] MPLS - MP-BPG with multiple OSPF areas You're right David. There are out of order no packets, only asynchronous traffic. Sorry about that... I don't think that only the supression would do the job, since the loopbacks will still be in different areas. 2011/10/18 David Prall <[email protected]> > Livio, > Where are you getting out of order packets? You do have asymmetric hop > counts, which most likely means asymmetric latency. But all the packets > should be in order. Could use DWDM so that each router isn't directly > connected and everything looks the same number of hops away, of course more > ports are required at the Area 10 edge. > > You can use prefix-suppression to only advertise the loopback using OSPF, > to > minimize the number of LSA's. Then use MPLS and BGP for all packet > forwarding, including the global table. > > David > > -- > http://dcp.dcptech.com > > > > -----Original Message----- > > From: [email protected] [mailto:cisco-nsp- > > [email protected]] On Behalf Of Livio Zanol Puppim > > Sent: Tuesday, October 18, 2011 9:34 PM > > To: [email protected] > > Subject: [c-nsp] MPLS - MP-BPG with multiple OSPF areas > > > > Hello everybody, > > > > I have a doubt with a lab design that we are creating to test some MPLS > > topologies. I would like to know if anybody can help me solve a problem > > that > > I am facing about routing paths. To help ilustrate the topology I'm > > sending > > the image link below. > > > > https://docs.google.com/leaf?id=0B4Hf34G524HsNTA3ZTc1NTItNmJlNi00ZDQyLW > > I1ZDAtYTg5MTliODRjMDhk&hl=en_US > > > > In the topology, I have two core routers interconnected with a 1 Gbps > > link > > and several other routers interconnected with a 100Mbps link. The > > interfaces > > between the core routers are in the OSPF area 0 and all other physical > > interfaces are in the OSPF area 10. Each one of the two core routers > > also > > have a connection to the area 10 using a 100Mbps interface. > > > > The router ID and the "update-source interface", on the core routers > > (PE1) > > is a loopback interface that belongs to the OSPF area 0. > > The router ID and the "update-source interface", on the access routers > > (PE6) > > is a loopback interface that belongs to the OSPF area 10. > > > > After establishing OSPF adjacencies between all routers, the BGP > > process > > starts to establish connection, and this undesirable behavior happens: > > > > When the router PE1 (area 0) wants to establish a BGP session with > > router > > PE6 (area 10), the packet flow through all 100Mbps (purple arrow). When > > the > > router PE6 (area 10) responds, the packet flow through the 1Gbps > > connection > > between the core routers (red arrow). Every flow that needs to use the > > LSPs > > will do logically the same, causing out-of-order packets at the > > network. > > > > I know that this is an expected behavior, as intra-area routes are > > preferred > > over inter-area routes, no matter what the link cost is. > > > > The question is: What solution do you guys think it's better for this > > scenario, so that the packet flow goes always through the optimal path? > > - Sham-links; > > - Extended area 0 to one more hop; > > - Change the "update-source interface" for area 10; > > - Create small areas between the core and access routers > > - Other solutions... > > > > We are planning to deploy a network with more than 200 PE routers in a > > similar scenario, and I don't think that a single OSPF area is a good > > choice > > for us. > > > > Can anybody help with some advice? > > > > -- > > []'s > > > > Lívio Zanol Puppim > > _______________________________________________ > > cisco-nsp mailing list [email protected] > > https://puck.nether.net/mailman/listinfo/cisco-nsp > > archive at http://puck.nether.net/pipermail/cisco-nsp/ > > -- []'s Lívio Zanol Puppim _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
