06-20-2006 09:40 PM - edited 03-03-2019 03:44 AM
Hi,
I have a routing problem on our distribution layer that I'd appreciated some help with.
We have 4 distrubution layer3 3750s (12.2 SEE) attached to core 6509 (SXF). Our distribution layer is configured in their own area (2) and the core is configured for dual areas (2 dist& 0 core).
When a distribution switch goes down it causes packet loss across the whole distrubution. It seems to be when both redundant links fail. From the config below can anyone see why it causes campus wide routing problems? Is this a know fault with OSPF..
router ospf 1
log-adjacency-changes
2 stub no-summary
passive-interface default
no passive-interface Port-channel1
no passive-interface Port-channel2
network xxlan.0.0.0 0.255.255.255 area 2
network xxxp2p.xxx.0.0 0.0.255.255 area 2
-----
interface Port-channel1
no switchport
ip address xxxp2p.xxx..yyy.yy 255.255.255.254
ip pim sparse-mode
ip ospf network point-to-point
ip ospf hello-interval 1
ip ospf dead-interval 3
ip ospf mtu-ignore
hold-queue 150 in
All links are setup in the manner, two on each dist. Any suggestions would be appreciated. Helpful posts rated.
06-20-2006 11:00 PM
"area 2 stub no-summary "
command has to be in 6509 bcos this core switch will be ABR and publish a default route to ur distribution switchs. in ur 3750's will have only "area 2 stub" command
ur hello timer manupulation has to consistence in ur network so that all the router will update to each other at consistence timing just check u configure the timers each and every interface in ospf domain same.
do u have multiple interface connected to core if yes than packet u will have equal cost load balancing and per-destination load balancing.
please rate if helps
HTH
06-20-2006 11:49 PM
I have both core & dist setup with:
area 2 stub no-summary
Are you saying best practice is to use
'area 2 stub'
On the dist layer?
Timers are consistant across campus. Thx for help.
06-21-2006 12:31 AM
area 2 stub no-summary need to configure on ABR coonected to area 0 so that you will have default route pointing to area 0 core.
Just check ur routing table u should have default route pointing to your core 1 and 2 only not any distribution switch 3750. if u have any default route in 3750 pointing to another 3750 distribution switch you need to filter it out but what i will suggest here is to put ur area 2 as stud only don't make it NSSA (not-so-stub area) so that u have all specific route from area 0 as well as default route in 3750's.
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