RE: OSPF question

From: Brian Dennis (bdennis@internetworkexpert.com)
Date: Thu Oct 06 2005 - 16:20:30 GMT-3


Vidhya,
        OSPF network types that use a DR (broadcast and non-broadcast)
can neighbor with each other and function properly. Likewise OSPF
network types that do not use a DR (point-to-point and
point-to-multipoint) can neighbor with each other and function properly.
But if you mix DR types with non-DR types they can become adjacent but
will not function properly as you have seen. You should see in the OSPF
database "Adv Router is not-reachable" messages when you've mixed DR and
non-DR types.

Also here is a link from Cisco that will help.

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a008009
481a.shtml#r1

HTH,

Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
bdennis@internetworkexpert.com
 
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 775-745-6404 (Outside the US and Canada)
 

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
vidhya natarajan
Sent: Thursday, October 06, 2005 12:08 PM
To: ccielab@groupstudy.com
Subject: OSPF question

Hi,

I encountered a strange(for me) ospf issue over NBMA.. I see the routes
in the ospf database and the neighbor state is full.. However, the
routes
arent seen in the routing table..

I have a FR-hub and 4 spokes.. FR hub is a
multipoint interface and the spokes 2 of them are physical FR interfaces
and 2
of them are point to point.. All the FR interfaces, ie., the hub
interface and
the 4 spoke interfaces are in area 0... Now, none of the IA routes are
seen in
Spokes that have serial point to point interfaces configured.... Im not
sure
if im missing the obvious.. Can anyone please help?

Hub:
HUB#sh run int
s0/0.1
Building configuration...

Current configuration : 250 bytes
!
interface Serial0/0.1 multipoint
 ip address 1.1.1.1 255.255.255.0
 ip ospf
hello-interval 10
 frame-relay interface-dlci 102
 frame-relay interface-dlci
103
 frame-relay interface-dlci 104
 frame-relay interface-dlci 105
end

HUB#
HUB#sh ip ospf nei

Neighbor ID Pri State Dead Time Address
Interface
22.22.22.22 0 FULL/DROTHER 00:00:32 1.1.1.2
Serial0/0.1
33.33.33.33 0 FULL/DROTHER 00:00:33 1.1.1.3
Serial0/0.1
44.44.44.44 0 FULL/DROTHER 00:00:34 1.1.1.4
Serial0/0.1
55.55.55.55 0 FULL/DROTHER 00:00:39 1.1.1.5
Serial0/0.1
HUB#
HUB#sh ip route ospf
     111.0.0.0/24 is subnetted, 1
subnets
O IA 111.1.1.0 [110/65] via 1.1.1.2, 00:30:29, Serial0/0.1
HUB#
============================================

Spoke 2

Spoke-2#sh run int s0/0
Building configuration...

Current configuration : 69 bytes
!
interface
Serial0/0
 no ip address
 encapsulation frame-relay
end

Spoke-2#sh run int
s0/0.1
Building configuration...

Current configuration : 133 bytes
!
interface Serial0/0.1 point-to-point
 ip address 1.1.1.3 255.255.255.0
 ip
ospf priority 0
 frame-relay interface-dlci 301
end

router ospf 11
log-adjacency-changes
 network 1.1.1.0 0.0.0.255 area 0
 network 33.33.33.33
0.0.0.0 area 0

Spoke-2#sh ip route ospf

Spoke-2#sh ip ospf nei

Neighbor
ID Pri State Dead Time Address Interface
12.2.2.1
0 FULL/ - 00:00:38 1.1.1.1 Serial0/0.1
Spoke-2#
Spoke-2#sh ip ospf database

            OSPF Router with ID (33.33.33.33)
(Process ID 11)

                Router Link States (Area 0)

Link ID
ADV Router Age Seq# Checksum Link count
12.2.2.1
12.2.2.1 988 0x8000000B 0x005032 2
22.22.22.22 22.22.22.22
1926 0x80000006 0x002B09 1
33.33.33.33 33.33.33.33 1285
0x80000009 0x00FBE7 3
44.44.44.44 44.44.44.44 261 0x80000003
0x00BBC9 1
55.55.55.55 55.55.55.55 329 0x80000004 0x00CA13 3
Net Link States (Area 0)

Link ID ADV Router Age Seq#
Checksum
1.1.1.1 12.2.2.1 235 0x80000006 0x009305
Summary Net Link States (Area 0)

Link ID ADV Router Age
Seq# Checksum
111.1.1.0 22.22.22.22 1922 0x80000001
0x003D35
!
===========================================================

Spoke
3 [where the 111.1.1.0 is installed.. ]
Spoke-3#sh ip ospf database
OSPF Router with ID (44.44.44.44) (Process ID 11)

                Router Link
States (Area 0)

Link ID ADV Router Age Seq#
Checksum Link count
12.2.2.1 12.2.2.1 1073 0x8000000B
0x005032 2
22.22.22.22 22.22.22.22 74 0x80000007 0x00290A 1
33.33.33.33 33.33.33.33 1371 0x80000009 0x00FBE7 3
44.44.44.44
44.44.44.44 343 0x80000003 0x00BBC9 1
55.55.55.55 55.55.55.55
413 0x80000004 0x00CA13 3

                Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
1.1.1.1
12.2.2.1 319 0x80000006 0x009305

                Summary Net
Link States (Area 0)

Link ID ADV Router Age Seq#
Checksum
111.1.1.0 22.22.22.22 74 0x80000002 0x003B36
Spoke-3#

Spoke-3#sh run int s0/0
Building configuration...

Current
configuration : 177 bytes
!
interface Serial0/0
 ip address 1.1.1.4
255.255.255.0
 encapsulation frame-relay
 ip ospf hello-interval 10
 ip ospf
priority 0
 frame-relay map ip 1.1.1.1 401 broadcast
end

Spoke-3#
Spoke-3#
Spoke-3#sh ip route ospf
     111.0.0.0/24 is subnetted, 1 subnets
O IA
111.1.1.0 [110/65] via 1.1.1.2, 00:34:16, Serial0/0
     11.0.0.0/32 is
subnetted, 1 subnets
O 11.11.11.11 [110/65] via 1.1.1.1, 00:34:16,
Serial0/0
Spoke-3#

Thanks,
Vidhya



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