From: Jason Sinclair (sinclairj@xxxxxxxxxxxxxxx)
Date: Mon May 27 2002 - 03:49:45 GMT-3
All,
As per RFC 2328:
"9.5. Sending Hello packets Hello packets are sent out each functioning
router interface. They are used to discover and maintain neighbor
relationships.[6] On broadcast and NBMA networks, Hello Packets are also
used to elect the Designated Router and Backup Designated Router. The format
of an Hello packet is detailed in Section A.3.2. The Hello Packet contains
the router's Router Priority (used in choosing the Designated Router), and
the interval between Hello Packets sent out the interface (HelloInterval).
The Hello Packet also indicates how often a neighbor must be heard from to
remain active (RouterDeadInterval). Both HelloInterval and
RouterDeadInterval must be the same for all routers attached to a common
network. The Hello packet also contains the IP address mask of the attached
network (Network Mask). On unnumbered point-to-point networks and on virtual
links this field should be set to 0.0.0.0. "
I think you may find this is why this works.
Regards,
Jason Sinclair CCIE #9100
Manager, Network Control Centre
POWERTEL
Ground Level, 55 Clarence Street,
SYDNEY NSW 2000
AUSTRALIA
office: + 61 2 8264 3820
mobile: + 61 416 105 858
* sinclairj@powertel.com.au
-----Original Message-----
From: Michael Snyder [mailto:msnyder@ldd.net]
Sent: Monday, 27 May 2002 16:05
To: 'mize'
Cc: ccielab@groupstudy.com
Subject: RE: This one will make your head hurt.
And the Tunnel Interface has what subnet in common? They are on
different Class A networks. I mean ospf has problems with
discontinuous
sub networks, never mind two different Class A networks. How would
that
hello packet work?
-----Original Message-----
From: mize [mailto:mize@netbuddy.org]
Sent: Monday, May 27, 2002 12:46 AM
To: Michael Snyder
Cc: ccielab@groupstudy.com
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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