From: Nick Shah (nshah@xxxxxxxxxxxxxx)
Date: Mon May 27 2002 - 03:26:34 GMT-3
nope. you could do the same thing on a serial interface as well..
so ..
int serial0
ip unnumbered loop0
on another router...
int serial0
ip unnumbered loop1
would work as well. Lets not forget that OSPF forms adjacency by sending
msgs. to multicast address. This feature has been documented (briefly) in
OSPF Q&A.
Nick
----- Original Message -----
From: "mize" <mize@netbuddy.org>
To: "Michael Snyder" <msnyder@ldd.net>
Cc: <ccielab@groupstudy.com>
Sent: Monday, May 27, 2002 3:46 PM
Subject: Re: This one will make your head hurt.
> Wonderful scenario but the reason is simple - OSPF in running on Tunnel 0
interface.
>
> !!!!
> >I'll let you figure it out. First take note that I can ping networks
> >1.1.1.1 and 3.3.3.3. Second notice that ospf has no subnets or
> >neighbors in common. None! Yet a full ospf database.
> >
> >
> >A#show run
> >Building configuration...
> >!
> >hostname A
> >!
> >interface Loopback0
> > ip address 1.1.1.1 255.255.255.0
> > ip ospf network point-to-point
> >!
> >interface Loopback1
> > ip address 2.2.2.2 255.255.255.0
> > ip ospf network point-to-point
> >!
> >interface Tunnel0
> > ip unnumbered Loopback1
> > tunnel source Loopback1
> > tunnel destination 4.4.4.4
> >!
> >interface Serial1
> > ip address 10.0.0.1 255.255.255.252
> > clockrate 56000
> >!
> >router ospf 80
> > log-adjacency-changes
> > network 1.1.1.0 0.0.0.255 area 1
> > network 2.2.2.0 0.0.0.255 area 0
> >!
> >ip route 4.4.4.0 255.255.255.0 Serial1
> >
> >A#si
> >
> >Gateway of last resort is not set
> >
> > 1.0.0.0/24 is subnetted, 1 subnets
> >C 1.1.1.0 is directly connected, Loopback0
> > 2.0.0.0/24 is subnetted, 1 subnets
> >C 2.2.2.0 is directly connected, Loopback1
> > 3.0.0.0/24 is subnetted, 1 subnets
> >O IA 3.3.3.0 [110/11112] via 4.4.4.4, 00:07:13, Tunnel0
> > 4.0.0.0/24 is subnetted, 1 subnets
> >S 4.4.4.0 is directly connected, Serial1
> > 10.0.0.0/30 is subnetted, 1 subnets
> >C 10.0.0.0 is directly connected, Serial1
> >A#p 3.3.3.3
> >
> >Type escape sequence to abort.
> >Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
> >!!!!!
> >Success rate is 100 percent (5/5), round-trip min/avg/max = 40/40/40 ms
> >A#show ip ospf n
> >
> >Neighbor ID Pri State Dead Time Address
> >Interface
> >4.4.4.4 1 FULL/ - 00:00:38 4.4.4.4
> >Tunnel0
> >A#show ip ospf d
> >
> > OSPF Router with ID (2.2.2.2) (Process ID 80)
> >
> >
> > Router Link States (Area 0)
> >
> >Link ID ADV Router Age Seq# Checksum Link
> >count
> >2.2.2.2 2.2.2.2 459 0x80000015 0xC28B 2
> >4.4.4.4 4.4.4.4 460 0x80000002 0x2A26 2
> >
> > Summary Net Link States (Area 0)
> >
> >Link ID ADV Router Age Seq# Checksum
> >1.1.1.0 2.2.2.2 496 0x80000001 0x33FD
> >3.3.3.0 4.4.4.4 455 0x80000002 0xAC75
> >
> > Router Link States (Area 1)
> >
> >Link ID ADV Router Age Seq# Checksum Link
> >count
> >2.2.2.2 2.2.2.2 233 0x80000004 0x77A3 1
> >
> > Summary Net Link States (Area 1)
> >
> >Link ID ADV Router Age Seq# Checksum
> >2.2.2.0 2.2.2.2 791 0x80000001 0xF1F
> >3.3.3.0 2.2.2.2 455 0x80000001 0x791F
> >4.4.4.0 2.2.2.2 455 0x80000001 0x5540
> >A#
> >
> >
> >
> >
> >
> >C#show run
> >Building configuration...
> >!
> >hostname C
> >!
> >!
> >!
> >interface Loopback0
> > ip address 3.3.3.3 255.255.255.0
> > ip ospf network point-to-point
> >!
> >interface Loopback1
> > ip address 4.4.4.4 255.255.255.0
> > ip ospf network point-to-point
> >!
> >interface Tunnel0
> > ip unnumbered Loopback1
> > tunnel source Loopback1
> > tunnel destination 2.2.2.2
> >!
> >interface Ethernet0
> > no ip address
> >!
> >interface Serial1
> > ip address 10.0.0.2 255.255.255.252
> >!
> >router ospf 80
> > log-adjacency-changes
> > network 3.3.3.0 0.0.0.255 area 2
> > network 4.4.4.0 0.0.0.255 area 0
> >!
> >ip classless
> >ip route 2.2.2.0 255.255.255.0 Serial1
> >!
> >end
> >
> >C#show ip route
> >Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
> > D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
> > N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
> > E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
> > i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS
> >inter area
> > * - candidate default, U - per-user static route, o - ODR
> > P - periodic downloaded static route
> >
> >Gateway of last resort is not set
> >
> > 1.0.0.0 0xFFFFFF00 is subnetted, 1 subnets
> >O IA 1.1.1.0 [110/11112] via 2.2.2.2, 00:05:27, Tunnel0
> > 2.0.0.0 0xFFFFFF00 is subnetted, 1 subnets
> >S 2.2.2.0 is directly connected, Serial1
> > 3.0.0.0 0xFFFFFF00 is subnetted, 1 subnets
> >C 3.3.3.0 is directly connected, Loopback0
> > 4.0.0.0 0xFFFFFF00 is subnetted, 1 subnets
> >C 4.4.4.0 is directly connected, Loopback1
> > 10.0.0.0 0xFFFFFFFC is subnetted, 1 subnets
> >C 10.0.0.0 is directly connected, Serial1
> >C#p 1.1.1.1
> >
> >Type escape sequence to abort.
> >Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
> >!!!!!
> >Success rate is 100 percent (5/5), round-trip min/avg/max = 44/50/64 ms
> >C#show ip ospf nei
> >
> >Neighbor ID Pri State Dead Time Address
> >Interface
> >2.2.2.2 1 FULL/ - 00:00:37 2.2.2.2
> >Tunnel0
> >C#show ip ospf data
> >
> > OSPF Router with ID (4.4.4.4) (Process ID 80)
> >
> >
> > Router Link States (Area 0)
> >
> >Link ID ADV Router Age Seq# Checksum Link
> >count
> >2.2.2.2 2.2.2.2 367 0x80000015 0xC28B 2
> >4.4.4.4 4.4.4.4 367 0x80000002 0x2A26 2
> >
> > Summary Net Link States (Area 0)
> >
> >Link ID ADV Router Age Seq# Checksum
> >1.1.1.0 2.2.2.2 404 0x80000001 0x33FD
> >3.3.3.0 4.4.4.4 362 0x80000002 0xAC75
> >
> > Router Link States (Area 2)
> >
> >Link ID ADV Router Age Seq# Checksum Link
> >count
> >4.4.4.4 4.4.4.4 376 0x80000001 0x15F2 1
> >
> > Summary Net Link States (Area 2)
> >
> >Link ID ADV Router Age Seq# Checksum
> >1.1.1.0 4.4.4.4 356 0x80000001 0x8511
> >2.2.2.0 4.4.4.4 358 0x80000001 0x6132
> >4.4.4.0 4.4.4.4 368 0x80000001 0x8A95
> >C#
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