RE: [IP Range with OSPF]

From: VAUTRIN Olivier (olivier.vautrin@xxxxxxxx)
Date: Fri Nov 02 2001 - 21:31:09 GMT-3


   
Yes, A is the endpoint of a virtual-link with B. But so is there a way to
summarize this network? Even if there is a virtual-link, RouterB must
summarize the address for all the other area (include the area 3 after the
virtual link).

I give you the database and the configuration of A:

RouterA#sh ip ospf database summary

       OSPF Router with ID (170.10.5.4) (Process ID 1)

                Summary Net Link States (Area 0)

  LS age: 983
  Options: (No TOS-capability, DC)
  LS Type: Summary Links(Network)
  Link State ID: 170.10.5.4 (summary Network Number)
  Advertising Router: 170.10.5.4
  LS Seq Number: 80000005
  Checksum: 0x7D3F
  Length: 28
  Network Mask: /32
        TOS: 0 Metric: 1

  LS age: 983
  Options: (No TOS-capability, DC)
  LS Type: Summary Links(Network)
  Link State ID: 170.10.9.5 (summary Network Number)
  Advertising Router: 170.10.5.4
  LS Seq Number: 80000003
  Checksum: 0xAFFF
  Length: 28
  Network Mask: /32
        TOS: 0 Metric: 11

  LS age: 150 (DoNotAge)
  Options: (No TOS-capability, DC)
  LS Type: Summary Links(Network)
  Link State ID: 170.10.9.5 (summary Network Number)
  Advertising Router: 170.10.9.5
  LS Seq Number: 80000005
  Checksum: 0x258D
  Length: 28
  Network Mask: /32
        TOS: 0 Metric: 1

  LS age: 986
  Options: (No TOS-capability, DC)
  LS Type: Summary Links(Network)
  Link State ID: 170.10.128.0 (summary Network Number)
  Advertising Router: 170.10.5.4
  LS Seq Number: 80000009
  Checksum: 0x2E49
  Length: 28
  Network Mask: /26
        TOS: 0 Metric: 10

  LS age: 1 (DoNotAge)
  Options: (No TOS-capability, DC)
  LS Type: Summary Links(Network)
  Link State ID: 170.10.128.0 (summary Network Number)
  Advertising Router: 170.10.9.5
  LS Seq Number: 8000000C
  Checksum: 0x669
  Length: 28
  Network Mask: /26
        TOS: 0 Metric: 10

                Summary Net Link States (Area 2)

  LS age: 987
  Options: (No TOS-capability, DC)
  LS Type: Summary Links(Network)
  Link State ID: 170.10.5.4 (summary Network Number)
  Advertising Router: 170.10.5.4
  LS Seq Number: 80000003
  Checksum: 0x813D
  Length: 28
  Network Mask: /32
        TOS: 0 Metric: 1

  LS age: 1137
  Options: (No TOS-capability, DC)
  LS Type: Summary Links(Network)
  Link State ID: 170.10.5.4 (summary Network Number)
  Advertising Router: 170.10.9.5
  LS Seq Number: 80000003
  Checksum: 0xC3EB
  Length: 28
  Network Mask: /32
        TOS: 0 Metric: 11

  LS age: 989
  Options: (No TOS-capability, DC)
  LS Type: Summary Links(Network)
  Link State ID: 170.10.7.0 (summary Network Number)
  Advertising Router: 170.10.5.4
  LS Seq Number: 80000004
  Checksum: 0x1471
  Length: 28
  Network Mask: /28
        TOS: 0 Metric: 74

  LS age: 1139
  Options: (No TOS-capability, DC)
  LS Type: Summary Links(Network)
  Link State ID: 170.10.7.0 (summary Network Number)
  Advertising Router: 170.10.9.5
  LS Seq Number: 80000002
  Checksum: 0xEB91
  Length: 28
  Network Mask: /24
        TOS: 0 Metric: 64

  LS age: 989
  Options: (No TOS-capability, DC)
  LS Type: Summary Links(Network)
  Link State ID: 170.10.8.0 (summary Network Number)
  Advertising Router: 170.10.5.4
  LS Seq Number: 80000002
  Checksum: 0xA2B4
  Length: 28
  Network Mask: /24
        TOS: 0 Metric: 1636

  LS age: 1139
  Options: (No TOS-capability, DC)
  LS Type: Summary Links(Network)
  Link State ID: 170.10.8.0 (summary Network Number)
  Advertising Router: 170.10.9.5
  LS Seq Number: 80000002
  Checksum: 0x1C40
  Length: 28
  Network Mask: /24
        TOS: 0 Metric: 1626

                Summary Net Link States (Area 3)

  LS age: 990
  Options: (No TOS-capability, DC)
  LS Type: Summary Links(Network)
  Link State ID: 170.10.7.0 (summary Network Number)
  Advertising Router: 170.10.5.4
  LS Seq Number: 80000004
  Checksum: 0x1471
  Length: 28
  Network Mask: /28
        TOS: 0 Metric: 74

  LS age: 990
  Options: (No TOS-capability, DC)
  LS Type: Summary Links(Network)
  Link State ID: 170.10.8.0 (summary Network Number)
  Advertising Router: 170.10.5.4
  LS Seq Number: 80000002
  Checksum: 0xA2B4
  Length: 28
  Network Mask: /24
        TOS: 0 Metric: 1636

  LS age: 991
  Options: (No TOS-capability, DC)
  LS Type: Summary Links(Network)
  Link State ID: 170.10.9.5 (summary Network Number)
  Advertising Router: 170.10.5.4
  LS Seq Number: 80000003
  Checksum: 0xAFFF
  Length: 28
  Network Mask: /32
        TOS: 0 Metric: 11

  LS age: 991
  Options: (No TOS-capability, DC)
  LS Type: Summary Links(Network)
  Link State ID: 170.10.128.0 (summary Network Number)
  Advertising Router: 170.10.5.4
  LS Seq Number: 80000003
  Checksum: 0x3A43
  Length: 28
  Network Mask: /26
        TOS: 0 Metric: 10

RouterA#

RouterA#sh ip ospf database

       OSPF Router with ID (170.10.5.4) (Process ID 1)

                Router Link States (Area 0)

Link ID ADV Router Age Seq# Checksum Link count
170.10.4.3 170.10.4.3 2 (DNA) 0x8000001A 0x3A12 3
170.10.5.4 170.10.5.4 587 0x80000013 0x8E0D 1
170.10.6.2 170.10.6.2 2 (DNA) 0x80000016 0x3A17 3
170.10.9.5 170.10.9.5 1 (DNA) 0x80000018 0xEAD6 2

                Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum
170.10.7.5 170.10.9.5 1 (DNA) 0x80000010 0xB4C2

                Summary Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum
170.10.5.4 170.10.5.4 951 0x80000005 0x7D3F
170.10.9.5 170.10.5.4 951 0x80000003 0xAFFF
170.10.9.5 170.10.9.5 150 (DNA) 0x80000005 0x258D
170.10.128.0 170.10.5.4 951 0x80000009 0x2E49
170.10.128.0 170.10.9.5 1 (DNA) 0x8000000C 0x669

                Summary ASB Link States (Area 0)

Link ID ADV Router Age Seq# Checksum
170.10.5.4 170.10.9.5 1 (DNA) 0x80000006 0xA507

                Router Link States (Area 2)

Link ID ADV Router Age Seq# Checksum Link count
170.10.5.4 170.10.5.4 588 0x80000017 0x9191 1
170.10.9.5 170.10.9.5 1101 0x80000011 0x7AD1 2

                Net Link States (Area 2)

Link ID ADV Router Age Seq# Checksum
170.10.128.4 170.10.5.4 588 0x80000008 0x9367

                Summary Net Link States (Area 2)

Link ID ADV Router Age Seq# Checksum
170.10.5.4 170.10.5.4 952 0x80000003 0x813D
170.10.5.4 170.10.9.5 1101 0x80000003 0xC3EB
170.10.7.0 170.10.5.4 952 0x80000004 0x1471
170.10.7.0 170.10.9.5 1102 0x80000002 0xEB91
170.10.8.0 170.10.5.4 952 0x80000002 0xA2B4
170.10.8.0 170.10.9.5 1102 0x80000002 0x1C40

                Summary ASB Link States (Area 2)

Link ID ADV Router Age Seq# Checksum
170.10.5.4 170.10.9.5 1102 0x80000003 0xAB04

                Router Link States (Area 3)

Link ID ADV Router Age Seq# Checksum Link count
170.10.5.4 170.10.5.4 590 0x8000000C 0x30BA 1

                Summary Net Link States (Area 3)

Link ID ADV Router Age Seq# Checksum
170.10.7.0 170.10.5.4 953 0x80000004 0x1471
170.10.8.0 170.10.5.4 953 0x80000002 0xA2B4
170.10.9.5 170.10.5.4 953 0x80000003 0xAFFF
170.10.128.0 170.10.5.4 953 0x80000003 0x3A43

                Type-5 AS External Link States

Link ID ADV Router Age Seq# Checksum Tag
170.10.1.0 170.10.5.4 590 0x80000007 0x2205 0
170.10.2.0 170.10.5.4 590 0x80000007 0x170F 0
170.10.3.0 170.10.5.4 590 0x80000007 0xC19 0
170.10.4.0 170.10.5.4 590 0x80000007 0x123 0
170.10.5.0 170.10.5.4 590 0x80000007 0xF52D 0
170.10.8.2 170.10.5.4 430 0x80000001 0xCC57 0
170.10.128.0 170.10.5.4 591 0x80000009 0xA302 0
RouterA#

RouterA#sh running-config
Building configuration...

Current configuration:
!
version 11.2
no service password-encryption
no service udp-small-servers
no service tcp-small-servers
!
hostname R27
!
enable secret 5 $1$v5Pi$wxtJexvfVjoHEqtyh5G141
!
ip subnet-zero
no ip domain-lookup
!
interface Loopback0
 ip address 170.10.5.4 255.255.255.0
!
interface Ethernet0
 ip address 192.19.15.4 255.255.255.0 secondary
 ip address 170.10.128.4 255.255.255.192
!
interface Serial0
 ip address 170.10.3.4 255.255.255.0
 no fair-queue
 clockrate 800000
!
interface Serial1
 ip address 170.10.2.4 255.255.255.0
!
interface BRI0
 no ip address
 shutdown
!
router ospf 1
 redistribute rip subnets
 redistribute igrp 1 subnets
 network 170.10.128.4 0.0.0.0 area 2
 network 170.10.5.4 0.0.0.0 area 3
 area 2 virtual-link 170.10.9.5
!
router rip
 redistribute ospf 1
 redistribute igrp 1
 passive-interface Ethernet0
 passive-interface Loopback0
 passive-interface Serial1
 network 170.10.0.0
 default-metric 1
!
router igrp 1
 redistribute ospf 1 metric 10000000 1 255 1 1500
 redistribute rip metric 10000000 1 255 1 1500
 passive-interface Ethernet0
 passive-interface Serial0
 network 170.10.0.0
!
ip classless
!
alias exec c conf t
alias exec r show ip route
alias exec s show run
alias exec b sho ip int brief
!
line con 0
 exec-timeout 0 0
 password c
 logging synchronous
line aux 0
 exec-timeout 0 0
 password c
 logging synchronous
line vty 0 4
 exec-timeout 0 0
 password c
 logging synchronous
 login
!
end

-----Message d'origine-----
De : Curtis Call [mailto:curtiscall@usa.net]
Envoyi : samedi 3 novembre 2001 00:50
@ : ccielab@groupstudy.com; VAUTRIN Olivier
Objet : Re: [IP Range with OSPF]

Is A the endpoint of a Virtual-Link with B? If so then that explains why
you
have an intra-area OSPF route (from area 0) for the network in question.
show
ip ospf database router and show ip ospf database summary on Router A would
be
beneficial to determining what is going on.

VAUTRIN Olivier <olivier.vautrin@arche.fr> wrote:
> Hello Everybody,
>
> I have a problem with the command "area # range..." with OSPF:
>
> I have this configuration:
>
> A----B----C
>
> A is in Area 2
> C is in Area 0
>
> A is connected to the Eth0 on my conf
> C is connected to my serial0
>
> I am using the command "area 0 range 170.10.7.0 255.255.255.0"
>
> But when I look at the Routing table of A, I get:
>
>
> routerA#r
> 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, * - candidate
> default
> U - per-user static route, o - ODR
>
> Gateway of last resort is not set
>
> 170.10.0.0/16 is variably subnetted, 10 subnets, 4 masks
> C 170.10.128.0/26 is directly connected, Ethernet0
> I 170.10.1.0/24 [100/8576] via 170.10.2.1, 00:00:11, Serial1
> C 170.10.2.0/24 is directly connected, Serial1
> C 170.10.3.0/24 is directly connected, Serial0
> R 170.10.4.0/24 [120/1] via 170.10.3.3, 00:00:11, Serial0
> C 170.10.5.0/24 is directly connected, Loopback0
> O 170.10.7.0/28 [110/74] via 170.10.128.5, 00:37:09, Ethernet0
> <----------????? (I would like to see /24!)
> O 170.10.8.0/24 [110/1636] via 170.10.128.5, 00:37:09, Ethernet0
> R 170.10.8.2/32 [120/1] via 170.10.3.3, 00:00:11, Serial0
> O 170.10.9.5/32 [110/11] via 170.10.128.5, 00:39:06, Ethernet0
> C 192.19.15.0/24 is directly connected, Ethernet0
> RouterA#
>
>
> Any ideas?
>
> Cheers,
> Olivier Vautrin.
>
> I am using version:
> RouterB#sh ver
> Cisco Internetwork Operating System Software
> IOS (tm) 2500 Software (C2500-JS-L), Version 11.2(26a), RELEASE SOFTWARE
> (fc1)
> Copyright (c) 1986-2001 by cisco Systems, Inc.
> Compiled Thu 07-Jun-01 08:27 by leccese
> Image text-base: 0x03040454, data-base: 0x00001000
>
> Here is the configuration of my router B:
>
> RouterB#sh run
> RouterB#sh running-config
> Building configuration...
>
> Current configuration:
> !
> version 11.2
> no service password-encryption
> no service udp-small-servers
> no service tcp-small-servers
> !
> hostname RouterB
> !
> enable secret 5 $1$Aftb$i8EXJYT93xVhw5/bQSiXY1
> !
> ip subnet-zero
> no ip domain-lookup
> !
> interface Loopback0
> ip address 170.10.9.5 255.255.255.0
> !
> interface Ethernet0
> ip address 170.10.128.5 255.255.255.192
> !
> interface Serial0
> ip address 170.10.7.5 255.255.255.240
> encapsulation frame-relay
> no fair-queue
> !
> interface Serial1
> no ip address
> shutdown
> !
> router ospf 1
> network 170.10.7.5 0.0.0.0 area 0
> network 170.10.128.5 0.0.0.0 area 2
> network 170.10.9.5 0.0.0.0 area 2
> neighbor 170.10.7.3
> neighbor 170.10.7.2
> area 0 range 170.10.7.0 255.255.255.0
> area 2 virtual-link 170.10.5.4
> !
> ip classless
> !
> alias exec c conf t
> alias exec r show ip route
> alias exec s show run
> alias exec b sho ip int brief
> !
> line con 0
> exec-timeout 0 0
> password c
> logging synchronous
> line aux 0
> exec-timeout 0 0
> password c
> logging synchronous
> line vty 0 4
> exec-timeout 0 0
> password c
> logging synchronous
> login
> !
> end
----------
curtiscall@usa.net
OSPF/BGP Practice Exams
www.boson.com\tests\Advanced.htm



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