Hallo! I am thinking of startig using ospf techology to set up higer redundancy but at the moment i am just there where i am trying out my first setup. I have read some books on the topic and now i am following the text from http://www.openbsd.org/papers/linuxtag06-network.pdf.
To follow the 'Distant-office - Local-office' part from page 7 i set up xen hvm hosts, configured networking and started ospfd daemons on both ends, when they start i belive things work as they should but after taking preferred link down and putting back up my ospf setup isnt adjusting to the change. I am sorry for the long letter but i decided to present my setup in appropriate detail so someone could point me to the right direction. Leaving out details my setup is like this ne1, 192.168.15.1 ---------- 192.168.15.254, ne1 metric 100, over 1st xen bridge distant local office office metric 10, over 2nd xen bridge ne2, 192.168.16.1 ---------- 192.168.16.254, ne2 ospfd.conf at distant office is router-id 0.0.0.2 redistribute connected # areas area 0.0.0.0 { interface ne1 { metric 100 } interface ne2 { metric 10 } } ospfd.conf at local office is router-id 0.0.0.1 redistribute connected # areas area 0.0.0.0 { interface ne1 { metric 100 } interface ne2 { metric 10 } } I started ospf like '# ospfd -vd'. 1. FIRST TEST - both links are up and things work And after ospf settles and things work i have at distant office (interesting why linkstate is unknown, because of xen?) # ospfctl show int Interface Address State HelloTimer Linkstate Uptime nc ac ne2 192.168.16.1/24 DR 00:00:07 unknown 00:02:33 1 1 ne1 192.168.15.1/24 DR 00:00:07 unknown 00:02:33 1 1 and neighborhood # ospfctl show nei ID Pri State DeadTime Address Iface Uptime 0.0.0.1 1 FULL/BCKUP 00:00:38 192.168.16.254 ne2 00:05:12 0.0.0.1 1 FULL/BCKUP 00:00:39 192.168.15.254 ne1 00:05:12 and rib c# ospfctl show rib Destination Nexthop Path Type Type Cost Uptime 0.0.0.1 192.168.16.254 Intra-Area Router 10 00:05:47 192.168.15.0/24 192.168.15.1 Intra-Area Network 100 00:05:52 192.168.16.0/24 192.168.16.1 Intra-Area Network 10 00:05:52 0.0.0.0/0 192.168.16.254 Type 1 ext Network 110 00:05:47 2. SECOND TEST - preferred ie with metric 10 link down Things work, at distant office i have # ospfctl show int Interface Address State HelloTimer Linkstate Uptime nc ac ne2 192.168.16.1/24 DR 00:00:06 unknown 00:15:45 1 0 ne1 192.168.15.1/24 DR 00:00:06 unknown 00:15:45 1 1 # ospfctl show nei ID Pri State DeadTime Address Iface Uptime 0.0.0.1 1 DOWN/OTHER 00:01:29 192.168.16.254 ne2 - 0.0.0.1 1 FULL/BCKUP 00:00:32 192.168.15.254 ne1 00:15:49 as i see, distant office learned new default route, very good # ospfctl show rib Destination Nexthop Path Type Type Cost Uptime 0.0.0.1 192.168.15.254 Intra-Area Router 100 00:02:12 192.168.15.0/24 192.168.15.1 Intra-Area Network 100 00:16:33 192.168.16.0/24 192.168.15.254 Intra-Area Network 110 00:02:12 0.0.0.0/0 192.168.15.254 Type 1 ext Network 200 00:02:12 3. THIRD TEST - preferred link is put back up Traffic flows but it isnt switching back to the preferred metric 10 link, at the distant office i have # ospfctl show int Interface Address State HelloTimer Linkstate Uptime nc ac ne2 192.168.16.1/24 DR 00:00:04 unknown 00:22:17 1 1 ne1 192.168.15.1/24 DR 00:00:04 unknown 00:22:17 1 1 for some reason state stays on FULL/OTHER # ospfctl show nei ID Pri State DeadTime Address Iface Uptime 0.0.0.1 1 FULL/OTHER 00:00:36 192.168.16.254 ne2 00:00:13 0.0.0.1 1 FULL/BCKUP 00:00:36 192.168.15.254 ne1 00:21:45 and routing stays on metric 100 link # ospfctl show rib Destination Nexthop Path Type Type Cost Uptime 0.0.0.1 192.168.15.254 Intra-Area Router 100 00:08:49 192.168.15.0/24 192.168.15.1 Intra-Area Network 100 00:23:10 192.168.16.0/24 192.168.16.1 Intra-Area Network 10 00:01:38 0.0.0.0/0 192.168.15.254 Type 1 ext Network 200 00:08:49 If i continue and take down the metric 10 link, then traffic stops and i get # ospfctl show nei ID Pri State DeadTime Address Iface Uptime 0.0.0.1 1 FULL/OTHER 00:00:37 192.168.16.254 ne2 00:07:52 0.0.0.1 1 DOWN/OTHER 00:00:03 192.168.15.254 ne1 - and when i put it back i dont get traffic and i have # ospfctl show nei ID Pri State DeadTime Address Iface Uptime 0.0.0.1 1 FULL/OTHER 00:00:33 192.168.16.254 ne2 00:09:37 0.0.0.1 1 FULL/OTHER 00:00:33 192.168.15.254 ne1 00:00:47 I can also confirm that i can ping over both links the other side, in those routers is pf disabled and looking at the traffic i see Hello messages being sent # tcpdump -ni ne2 tcpdump: listening on ne2, link-type EN10MB 17:59:24.903057 192.168.16.1 > 224.0.0.5: OSPFv2-hello 48: rtrid 0.0.0.2 backbone dr 192.168.16.1 [tos 0xc0] [ttl 1] 17:59:24.903388 192.168.16.254 > 224.0.0.5: OSPFv2-hello 48: rtrid 0.0.0.1 backbone dr 192.168.16.254 [tos 0xc0] [ttl 1] 17:59:34.913201 192.168.16.1 > 224.0.0.5: OSPFv2-hello 48: rtrid 0.0.0.2 backbone dr 192.168.16.1 [tos 0xc0] [ttl 1] 17:59:34.913442 192.168.16.254 > 224.0.0.5: OSPFv2-hello 48: rtrid 0.0.0.1 backbone dr 192.168.16.254 [tos 0xc0] [ttl 1] I would be very thankful i somebody could take me forward from here. Best regards, Imre PS During these tests the local office displayed similar output.