From: Justin Menga (Justin.Menga@xxxxxxxxxxxxxxxxxx)
Date: Thu Oct 19 2000 - 19:52:44 GMT-3
Looking more closely at your config - be very CAREFUL with your network
types.
OSPF will not form adjacencies if Hello and Dead timers do not match. Thus
your network types must be configured so that these MATCH, otherwise NO
adjacency.
The Hello and Dead timers vary for different network types as follows:
broadcast: H 10 D 40
non-broadcast: H 30 D 120
point-to-point: H 10 D 40
point-to-multipoint: H 30 D120
If you debug ip ospf events you should see a Mismatched parameters message
appear......
Regards,
Justin Menga MCSE+I CCNP CCSE ASE
WAN Specialist
Computerland New Zealand
PO Box 3631, Auckland
DDI: (+64) 9 360 4864 Mobile: (+64) 25 349 599
mailto: justin.menga@computerland.co.nz
-----Original Message-----
From: mannan venkatesan [mailto:venkat_m@ins.com]
Sent: Friday, 20 October 2000 2:42 a.m.
To: 'Justin Menga'; ccielab@groupstudy.com
Subject: RE: OSPF Problem - Area BACKBONE(0) (Inactive)
Hi,
Thank you all for your feedbacks. Last night I was trying to configure a
simple P-O-P ospf config. over FR which I have done many times before. But I
couldn't get it work. I was able to ping from one router to other. In R1, sh
ip ospf showed 'Area BACKBONE(0) (Inactive) '. I don't understand why area 0
is inactive. Can someone help me?
Thanks,
Mannan
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Justin Menga
Sent: Wednesday, October 18, 2000 7:08 PM
To: 'mannan venkatesan'; ccielab@groupstudy.com
Subject: RE: OSPF Problem
Network was broken because R3 is the DR and can't communicate with R2 for
the Type 2 LSA. Try using ip ospf priority 0 on R3 on the subinterface to
force R1 to become the DR.
The hub always should be the DR..........
Regards,
Justin Menga MCSE+I CCNP CCSE ASE
WAN Specialist
Computerland New Zealand
PO Box 3631, Auckland
DDI: (+64) 9 360 4864 Mobile: (+64) 25 349 599
mailto: justin.menga@computerland.co.nz
-----Original Message-----
From: mannan venkatesan [mailto:venkat_m@ins.com]
Sent: Wednesday, 18 October 2000 4:07 a.m.
To: ccielab@groupstudy.com
Subject: OSPF Problem
Hi,
I was playing in ospf over FR lab and came across an interesting problem(I
was trying to simulate the problem we had in our client production network).
I configured R1 as hub (sub-ifs) and R2 and R3 as spoke (physical
interface). Here the config,
R1 :
interface Serial0.1 point-to-point
ip address 10.1.0.1 255.255.0.0
ip ospf network broadcast
frame-relay interface-dlci 100
!
interface Serial0.2 point-to-point
ip address 10.2.0.1 255.255.0.0
ip ospf network Point-to-multipoint
frame-relay interface-dlci 103
router ospf 10
network 10.0.0.0 0.255.255.255 area 0
R2 :
interface Serial0
ip address 10.1.0.2 255.255.0.0
encapsulation frame-relay
ip ospf network Point-to-multipoint
frame-relay map ip 10.1.0.1 106
router ospf 10
network 10.0.0.0 0.255.255.255 area 0
R3:
interface Serial0
ip address 10.2.0.2 255.255.0.0
encapsulation frame-relay
ip ospf network Point-to-multipoint
frame-relay map ip 10.2.0.1 106
router ospf 10
network 10.0.0.0 0.255.255.255 area 0
It worked fine with this config. Then I changed OSPF network type to
"Broadcast" in s0 of R3 and s0.2 of R1. R3 became DR and R1 became BDR.
After I changed OSPF network type to "Broadcast" in s0.1 of R1 and s0 of R2.
As soon as I entered network type 'broadcast' in R2, the network broke. I
couldn't access any of the routers for 5 minutes.
Now 'sh ip ospf nei' command shows,
R1:
Neighbor ID Pri State Dead Time Address Interface
10.1.0.2 1 FULL/BDR 00:00:39 10.1.0.2 Serial0.1
10.2.0.2 1 FULL/BDR 00:00:37 10.2.0.2 Serial0.2
R2:
Neighbor ID Pri State Dead Time Address Interface
10.2.0.1 1 FULL/DR 00:00:31 10.1.0.1 Serial0
R3:
Neighbor ID Pri State Dead Time Address Interface
10.2.0.1 1 FULL/DR 00:00:39 10.2.0.1 Serial0
I know DR and BDR election was going on, but why the network broke? During
election, routers multicast packets and we have only 3 routers. So, what
traffic did the routers send here? Can I have multiple OSPF network in one
broadcast medium? Can someone clarify my questions? Think I am missing
something here.
Thanks,
Mannan Venkatesan
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 08:25:28 GMT-3