From: VAUTRIN Olivier (olivier.vautrin@xxxxxxxx)
Date: Fri Nov 02 2001 - 22:20:03 GMT-3
It seems clear now!
Thx very much.
But I still need a /24 on A. The reason is that I have another router (we
can call it D) that is connected with A in IGRP. I am doing a redistribution
from OSPF to IGRP, so I need a /24.
I tried "summary-address 170.10.7.0 255.255.255.0" on RouterA and it is
working well.
-----Message d'origine-----
De : Curtis Call [mailto:curtiscall@usa.net]
Envoyi : samedi 3 novembre 2001 02:13
@ : ccielab@groupstudy.com; VAUTRIN Olivier
Objet : Re: [RE: [IP Range with OSPF]]
Aah, very devious. Here is what is occuring:
Router B has interface 170.10.7.0/28 in area 0. This is advertised as is in
it's Router LSA within area 0. In addition, as an ABR it will transmit a
Network Summary LSA into Area 2 which will contain 170.10.7.0/24 (due to the
area range). This Network Summary LSA can be seen within Area 2's database.
Now onto Router A...
Router A has a virtual-link to Router B. Router A receives the Router LSA
within Area 0 from Router B and installs the 170.10.7.0/28 LSA into it's
routing table. Router A also receives the Network Summary LSA for
170.10.7.0/24 from Area 2. Now here is the fun part. Because Router A is
an
ABR it will ONLY examine Network Summary LSAs from the backbone so any
summary
LSAs in other areas (area 2 and area 3) will not be examined and will NOT be
added to the routing table. Finally, when Router A creates it's Network
Summary LSAs it will consult it's own routing table (not link state
database)
and as such only the /28 will be advertised into area 3.
To cause the summary to go into area 3 just add an area range statement (for
area 3) on A. Not sure how you could get a summary to show up on A
though...why do you want to? :-)
VAUTRIN Olivier <olivier.vautrin@arche.fr> wrote:
> 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
>
----------
curtiscall@usa.net
OSPF/BGP Practice Exams
www.boson.com\tests\Advanced.htm
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