Re: virtual links over ip unnumbered

From: Vytautas Valancius (valas@mail.lt)
Date: Sat Nov 20 2004 - 19:51:50 GMT-3


Hi,

Below are super simple configurations for two routers connected with serial
line.

Virtual links are down even in this simple config. Network 172.16.100.0/24
is not in R1 because of that. As I said more interesting things happen when
we have complex ISDN setup, but I guess before debuging that one should
understand why this simple configuration is not working...

There are no error messages. 'debug ip ospf adj' does not show any output.
'debug ip ospf packet' behaves as there is no virtual link configured - no
packets are sent ir received to establish it.

R1:
!
interface Loopback1
 description area 0
 ip address 172.16.1.1 255.255.255.0
 ip ospf network point-to-point
!
interface Loopback101
 ip address 172.16.101.1 255.255.255.0
 ip ospf network point-to-point
!
interface Serial4/6
 ip unnumbered Loopback101
!
router ospf 1
 router-id 172.16.101.1
 log-adjacency-changes
 area 16 virtual-link 172.16.106.1
 passive-interface Loopback1
 network 172.16.1.1 0.0.0.0 area 0
 network 172.16.101.1 0.0.0.0 area 16
!

R1#sh ip ospf nei

Neighbor ID Pri State Dead Time Address Interface
172.16.106.1 1 FULL/ - 00:00:39 172.16.106.1 Serial4/6

R1#sh ip ospf virtual-links
Virtual Link OSPF_VL0 to router 172.16.106.1 is down
  Run as demand circuit
  DoNotAge LSA allowed.
  Transit area 16, Cost of using 65535
  Transmit Delay is 1 sec, State DOWN,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

R1#ping 172.16.106.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.106.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/16/20 ms
R1#sh ip ro
Gateway of last resort is not set

     172.16.0.0/24 is subnetted, 3 subnets
C 172.16.1.0 is directly connected, Loopback1
O 172.16.106.0 [110/782] via 172.16.106.1, 00:04:47, Serial4/6
C 172.16.101.0 is directly connected, Loopback101

R6 output:
!
interface Loopback100
 description area 100
 ip address 172.16.100.1 255.255.255.0
 ip ospf network point-to-point
!
interface Loopback106
 ip address 172.16.106.1 255.255.255.0
 ip ospf network point-to-point
!
interface Serial0
 ip unnumbered Loopback106
 no fair-queue
 clockrate 125000
!
interface Serial1
 no ip address
 shutdown
!
router ospf 1
 router-id 172.16.106.1
 log-adjacency-changes
 area 16 virtual-link 172.16.101.1
 network 172.16.100.1 0.0.0.0 area 100
 network 172.16.106.1 0.0.0.0 area 16
!
R6#sh ip ospf nei

Neighbor ID Pri State Dead Time Address Interface
172.16.101.1 1 FULL/ - 00:00:33 172.16.101.1 Serial0
R6#
R6#sh ip os
R6#sh ip ospf vir
Virtual Link OSPF_VL0 to router 172.16.101.1 is down
  Run as demand circuit
  DoNotAge LSA allowed.
  Transit area 16, Cost of using 65535
  Transmit Delay is 1 sec, State DOWN,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

R6#ping 172.16.101.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.101.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/16/20 ms
R6#
R6#sh ip ro

Gateway of last resort is not set

     172.16.0.0/24 is subnetted, 4 subnets
O IA 172.16.1.0 [110/65] via 172.16.101.1, 00:04:34, Serial0
C 172.16.106.0 is directly connected, Loopback106
C 172.16.100.0 is directly connected, Loopback100
O 172.16.101.0 [110/65] via 172.16.101.1, 00:04:44, Serial0

----- Original Message -----
From: "ccie2be" <ccie2be@nyc.rr.com>
To: "Vytautas Valancius" <valas@mail.lt>; <ccielab@groupstudy.com>
Sent: Sunday, November 21, 2004 12:59 AM
Subject: Re: virtual links over ip unnumbered

> Could you post your configuration? Including show command output? And,
> error messages?
> ----- Original Message -----
> From: "Vytautas Valancius" <valas@mail.lt>
> To: <ccielab@groupstudy.com>
> Sent: Saturday, November 20, 2004 2:37 PM
> Subject: virtual links over ip unnumbered
>
>
> > Hi Group,
> >
> > Does OSPF virtual-link work over link with ip unnumbered on both sides?
> >
> > I did not succed to run it in pretty basic setups. Moreover, if I run it
> > over unnumbered ISDN, demand-circuit feature is not working. Virtual
link
> is
> > UP only on one side and it keeps sending OSPF messages that brings ISDN
up
> > imediatelly after it goes down.
> >
> > Any comments are welcomed!
> >
> > valas
> >
> > _______________________________________________________________________
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html



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