OSPF – www.expertcisco.fr https://www.expertcisco.fr CCIE Routing and Switching Lab Exam Wed, 30 Jan 2013 08:28:42 +0000 fr-FR hourly 1 https://wordpress.org/?v=5.4 OSPFv3 – LSA Type https://www.expertcisco.fr/ipv6/ospfv3-lsa-type Sun, 20 Jan 2013 08:20:37 +0000 http://www.expertcisco.fr/?p=613 Continue reading →]]>

  • U- indicates how a router should handle unknown LSA. 
  • 0= treat the LSA as if it had link-local flooding scope
  • 1= Store and flood the LSA
  • S2 and S1- indicate flooding scope of the LSA
S2  S1  Description
 0  0  Link-local flooding
 0  1  Area scope flooding
 1  0  AS scope flooding
 1  1  Reserved

LSA Function Code– defines LSA’s specific functionality.

 LSA Function Code  LS Type
  Description
 1  0x2001  Router LSA
 2  0x2002  Network LSA
 3  0x2003  Inter-Area Prefix LSA
 4  0x2004  Inter-Area Router LSA
 5  0x4005  AS-external LSA
 6  0x2006  Group Membership LSA
 7  0x2007  Type-7 (NSSA) LSA
 8  0x0008  Link LSA
 9  0x2009  Intra-Area Prefix LSA
]]> OSPF Point-to-Point Networks https://www.expertcisco.fr/ospf/ospf-point-to-point-networks Thu, 13 Dec 2012 13:59:40 +0000 http://www.expertcisco.fr/?p=442 Continue reading →]]> OSPF – Hub and spoke Topology

Dans une architecture « Hub and spoke » Frame relay, les interfaces peuvent être configurées dans 4 modes de communication OSPF :

R1(config)#int s0/0
R1(config-if)#ip ospf network ?
broadcast       Specify OSPF broadcast multi-access network
non-broadcast       Specify OSPF NBMA network
point-to-multipoint Specify  OSPF point-to-multipoint network
point-to-point      Specify OSPF point-to-point network

 

Configuration d’une sous interface point à point sur chaque routeur

Configuration de R1 :

interface Serial0/0
 no ip address
 encapsulation frame-relay
!
interface Serial0/0.12 point-to-point
 ip address 10.1.12.1 255.255.255.0
 frame-relay interface-dlci 102
!
interface Serial0/0.13 point-to-point
 ip address 10.1.13.1 255.255.255.0
 frame-relay interface-dlci 103
!
interface Serial0/0.14 point-to-point
 ip address 10.1.14.1 255.255.255.0
 frame-relay interface-dlci 104
!
router ospf 1
 log-adjacency-changes
 network 1.1.1.1 0.0.0.0 area 0
 network 10.1.12.1 0.0.0.0 area 0
 network 10.1.13.1 0.0.0.0 area 0
 network 10.1.14.1 0.0.0.0 area 0
!

Vérifications :

R1#show ip ospf int s0/0
%OSPF: OSPF not enabled on Serial0/0
R1#show ip ospf int s0/0.12
Serial0/0.12 is up, line protocol is up
  Internet Address 10.1.12.1/24, Area 0
  Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:09
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 2.2.2.2
  Suppress hello for 0 neighbor(s)
R1#show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
4.4.4.4           0   FULL/  -        00:00:36    10.1.14.4       Serial0/0.14
3.3.3.3           0   FULL/  -        00:00:31    10.1.13.3       Serial0/0.13
2.2.2.2           0   FULL/  -        00:00:34    10.1.12.2       Serial0/0.12
  
R1#show ip route ospf
O    2.0.0.0/8 [110/65] via 10.1.12.2, 00:05:20, Serial0/0.12
O    3.0.0.0/8 [110/65] via 10.1.13.3, 00:05:20, Serial0/0.13
O    4.0.0.0/8 [110/65] via 10.1.14.4, 00:05:20, Serial0/0.14
R4#show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
1.1.1.1           0   FULL/  -        00:00:30    10.1.14.1       Serial0/0.41

Dans cette configuration, le routage des routeurs « spoke » converge vers le routeur « hub » :

R4#show ip route ospf
O    1.0.0.0/8 [110/65] via 10.1.14.1, 00:02:44, Serial0/0.41
O    2.0.0.0/8 [110/129] via 10.1.14.1, 00:02:44, Serial0/0.41
O    3.0.0.0/8 [110/129] via 10.1.14.1, 00:02:44, Serial0/0.41
     10.0.0.0/24 is subnetted, 3 subnets
O       10.1.13.0 [110/128] via 10.1.14.1, 00:02:44, Serial0/0.41
O       10.1.12.0 [110/128] via 10.1.14.1, 00:02:44, Serial0/0.41
]]> Priority OSPF https://www.expertcisco.fr/ospf/priority-ospf Fri, 20 Apr 2012 14:04:48 +0000 http://www.expertcisco.fr/?p=448 Continue reading →]]> Une priorité peut être configurée pour facilité l’élection du « Designated Router » (DR)

Dans une architecture « hub and spoke » en mode broadcast le routeur « hub » doit être élue DR en lui assignant la plus forte priorité(255), les routeur « spoke » doivent être configuré avec un priorité de 0

Configuration du routeur « hub » (R1)

R1(config)#int s0/0
R1(config-if)#ip ospf priority 255

Configuration des routeurs spoke (R2 à R4)

R4(config)#int s0/0
R4(config-if)#ip ospf priority 0

Vérifications:

R1#show ip ospf int s0/0
Serial0/0 is up, line protocol is up
  Internet Address 10.1.1.1/24, Area 0
  Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 64
  Transmit Delay is 1 sec, State DR, Priority 255
  Designated Router (ID) 1.1.1.1, Interface address 10.1.1.1
  No backup designated router on this network
  Old designated Router (ID) 4.4.4.4, Interface address 10.1.1.4
  Timer intervals configured, Hello 5, Dead 20, Wait 20, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:04
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 4 msec
  Neighbor Count is 3, Adjacent neighbor count is 3
    Adjacent with neighbor 2.2.2.2
    Adjacent with neighbor 3.3.3.3
    Adjacent with neighbor 4.4.4.4
  Suppress hello for 0 neighbor(s)
 
R4#show ip ospf int s0/0
Serial0/0 is up, line protocol is up
  Internet Address 10.1.1.4/24, Area 0
  Process ID 1, Router ID 4.4.4.4, Network Type BROADCAST, Cost: 64
  Transmit Delay is 1 sec, State DROTHER, Priority 0
  Designated Router (ID) 1.1.1.1, Interface address 10.1.1.1
  No backup designated router on this network
  Old designated Router (ID) 4.4.4.4, Interface address 10.1.1.4
  Flush timer for old DR LSA due in 00:00:36
  Timer intervals configured, Hello 5, Dead 20, Wait 20, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:03
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 1.1.1.1  (Designated Router)
  Suppress hello for 0 neighbor(s)
]]> OSPF Point-to-Multipoint Networks https://www.expertcisco.fr/frame-relay/ospf-point-to-multipoint-networks Fri, 20 Apr 2012 14:03:12 +0000 http://www.expertcisco.fr/?p=445 Continue reading →]]> OSPF – Hub and spoke Topology

Dans une architecture « Hub and spoke » Frame relay, les interfaces peuvent être configurées dans 4 modes de communication OSPF :

R1(config)#int s0/0
R1(config-if)#ip ospf network ?
broadcast       Specify OSPF broadcast multi-access network
non-broadcast       Specify OSPF NBMA network
point-to-multipoint Specify  OSPF point-to-multipoint network
point-to-point      Specify OSPF point-to-point network

 

Configuration de tous les routeurs en mode « point-to-mulitipoint »

R1#configure t
R1(config)#int s0/0
R1(config-if)#ip ospf network point-to-multipoint

Vérifications

R1#show ip ospf interface s0/0
Serial0/0 is up, line protocol is up
  Internet Address 10.1.1.1/24, Area 0
  Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_MULTIPOINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_MULTIPOINT,
  Timer intervals configured, Hello 5, Dead 20, Wait 20, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:03
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 2, maximum is 2
  Last flood scan time is 0 msec, maximum is 4 msec
  Neighbor Count is 3, Adjacent neighbor count is 3
    Adjacent with neighbor 4.4.4.4
    Adjacent with neighbor 3.3.3.3
    Adjacent with neighbor 2.2.2.2
  Suppress hello for 0 neighbor(s)

Dans cette configuration, le routage des routeurs « spoke » converge vers le routeur « hub » , une route host (/32) est également ajoutée :

R1#show ip route ospf
O    2.0.0.0/8 [110/65] via 10.1.1.2, 00:01:47, Serial0/0
O    3.0.0.0/8 [110/65] via 10.1.1.3, 00:01:47, Serial0/0
O    4.0.0.0/8 [110/65] via 10.1.1.4, 00:01:47, Serial0/0
     10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
O       10.1.1.2/32 [110/64] via 10.1.1.2, 00:01:47, Serial0/0
O       10.1.1.3/32 [110/64] via 10.1.1.3, 00:01:47, Serial0/0
O       10.1.1.4/32 [110/64] via 10.1.1.4, 00:01:47, Serial0/0

R2#show ip route ospf
O    1.0.0.0/8 [110/65] via 10.1.1.1, 00:02:15, Serial0/0
O    3.0.0.0/8 [110/129] via 10.1.1.1, 00:02:15, Serial0/0
O    4.0.0.0/8 [110/129] via 10.1.1.1, 00:02:15, Serial0/0
     10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
O       10.1.1.3/32 [110/128] via 10.1.1.1, 00:02:15, Serial0/0
O       10.1.1.1/32 [110/64] via 10.1.1.1, 00:02:15, Serial0/0
O       10.1.1.4/32 [110/128] via 10.1.1.1, 00:02:15, Serial0/0

R3#show ip route ospf
O    1.0.0.0/8 [110/782] via 10.1.1.1, 00:02:32, Serial1/0
O    2.0.0.0/8 [110/846] via 10.1.1.1, 00:02:32, Serial1/0
O    4.0.0.0/8 [110/846] via 10.1.1.1, 00:02:32, Serial1/0
     10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
O       10.1.1.2/32 [110/845] via 10.1.1.1, 00:02:32, Serial1/0
O       10.1.1.1/32 [110/781] via 10.1.1.1, 00:02:32, Serial1/0
O       10.1.1.4/32 [110/845] via 10.1.1.1, 00:02:32, Serial1/0

R4#show ip route ospf
O    1.0.0.0/8 [110/65] via 10.1.1.1, 00:02:50, Serial0/0
O    2.0.0.0/8 [110/129] via 10.1.1.1, 00:02:50, Serial0/0
O    3.0.0.0/8 [110/129] via 10.1.1.1, 00:02:50, Serial0/0
     10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
O       10.1.1.2/32 [110/128] via 10.1.1.1, 00:02:50, Serial0/0
O       10.1.1.3/32 [110/128] via 10.1.1.1, 00:02:50, Serial0/0
O       10.1.1.1/32 [110/64] via 10.1.1.1, 00:02:50, Serial0/0
]]> OSPF Broadcast Networks https://www.expertcisco.fr/frame-relay/ospf-broadcast-networks Fri, 20 Apr 2012 13:50:39 +0000 http://www.expertcisco.fr/?p=440 Continue reading →]]> OSPF – Hub and spoke Topology

Dans une architecture « Hub and spoke » Frame relay, les interfaces peuvent être configurées dans 4 modes de communication OSPF :

R1(config)#int s0/0
R1(config-if)#ip ospf network ?
broadcast       Specify OSPF broadcast multi-access network
non-broadcast       Specify OSPF NBMA network
point-to-multipoint Specify  OSPF point-to-multipoint network
point-to-point      Specify OSPF point-to-point network

 

Configuration des interaces de  tous les routeurs en mode broadcast

R1#conf t
R1(config)#int s0/0
R1(config-if)#ip ospf network broadcast

Dans cette configuration, la découverte de voisins OSPF est automatique

Vérifications:

R1#show ip ospf interface s0/0
Serial0/0 is up, line protocol is up
  Internet Address 10.1.1.1/24, Area 0
  Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 64
  Transmit Delay is 1 sec, State DR, Priority 255
  Designated Router (ID) 1.1.1.1, Interface address 10.1.1.1
  No backup designated router on this network
  Timer intervals configured, Hello 5, Dead 20, Wait 20, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:03
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 1, maximum is 2
  Last flood scan time is 0 msec, maximum is 4 msec
  Neighbor Count is 3, Adjacent neighbor count is 3
    Adjacent with neighbor 2.2.2.2
    Adjacent with neighbor 3.3.3.3
    Adjacent with neighbor 4.4.4.4   
  Suppress hello for 0 neighbor(s)
R1#show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
2.2.2.2           0   FULL/DROTHER    00:00:19    10.1.1.2        Serial0/0
3.3.3.3           0   FULL/DROTHER    00:00:15    10.1.1.3        Serial0/0
4.4.4.4           0   FULL/DROTHER    00:00:16    10.1.1.4        Serial0/0

Dans ce mode, les routeurs « spoke » obtiennent les IP des autres « spoke » comme next hop, la configuration frame relay doit permettre d’atteindre tous les next hop

R1#show ip route ospf
O    2.0.0.0/8 [110/65] via 10.1.1.2, 00:03:59, Serial0/0
O    3.0.0.0/8 [110/65] via 10.1.1.3, 00:03:59, Serial0/0
O    4.0.0.0/8 [110/65] via 10.1.1.4, 00:03:59, Serial0/0

R2#show ip  route ospf
O    1.0.0.0/8 [110/65] via 10.1.1.1, 00:07:11, Serial0/0
O    3.0.0.0/8 [110/65] via 10.1.1.3, 00:07:11, Serial0/0
O    4.0.0.0/8 [110/65] via 10.1.1.4, 00:07:11, Serial0/0

R3#show ip route ospf
O    1.0.0.0/8 [110/782] via 10.1.1.1, 00:07:29, Serial1/0
O    2.0.0.0/8 [110/782] via 10.1.1.2, 00:07:29, Serial1/0
O    4.0.0.0/8 [110/782] via 10.1.1.4, 00:07:29, Serial1/0

R4#show ip route ospf
O    1.0.0.0/8 [110/65] via 10.1.1.1, 00:07:46, Serial0/0
O    2.0.0.0/8 [110/65] via 10.1.1.2, 00:07:46, Serial0/0
O    3.0.0.0/8 [110/65] via 10.1.1.3, 00:07:46, Serial0/0
]]> OSPF Non-Broadcast Networks https://www.expertcisco.fr/frame-relay/ospf-non-broadcast-networks Fri, 20 Apr 2012 11:02:57 +0000 http://www.expertcisco.fr/?p=427 Continue reading →]]> OSPF – Hub and spoke Topology

Dans une architecture « Hub and spoke » Frame relay, les interfaces peuvent être configurées dans 4 modes de communication OSPF :

R1(config)#int s0/0
R1(config-if)#ip ospf network ?
broadcast       Specify OSPF broadcast multi-access network
non-broadcast       Specify OSPF NBMA network
point-to-multipoint Specify  OSPF point-to-multipoint network
point-to-point      Specify OSPF point-to-point network

 

Par défaut, les interfaces sérial sont en mode « Non-Broadcast »

Configuration basique de R1 (et des autres routeurs)

router ospf 1
 log-adjacency-changes
 network 1.1.1.1 0.0.0.0 area 0
 network 10.1.1.1 0.0.0.0 area 0
R1#show ip ospf interface s0/0
Serial0/0 is up, line protocol is up
  Internet Address 10.1.1.1/24, Area 0
  Process ID 1, Router ID 1.1.1.1, Network Type NON_BROADCAST, Cost: 64
  Transmit Delay is 1 sec, State WAITING, Priority 1
  No designated router on this network
  No backup designated router on this network
  Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5
    oob-resync timeout 120
    Hello due in 00:00:12
    Wait time before Designated router selection 00:01:12
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 0, maximum is 0
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 0, Adjacent neighbor count is 0
  Suppress hello for 0 neighbor(s)

 

Dans cette configuration, les voisins OSPF doivent être spécifiés sur le routeur hub :

R1#conf t
R1(config)#router ospf 1
R1(config-router)#
R1(config-router)#neighbor 10.1.1.2
R1(config-router)#neighbor 10.1.1.3
R1(config-router)#neighbor 10.1.1.4

Vérifications:

R1#show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
4.4.4.4           0   FULL/DROTHER    968 msec    10.1.1.4        Serial0/0
3.3.3.3           0   FULL/DROTHER    932 msec    10.1.1.3        Serial0/0
2.2.2.2           0   FULL/DROTHER    944 msec    10.1.1.2        Serial0/0
  
R1#show ip route ospf
O    2.0.0.0/8 [110/65] via 10.1.1.2, 00:00:45, Serial0/0
O    3.0.0.0/8 [110/65] via 10.1.1.3, 00:00:45, Serial0/0
O    4.0.0.0/8 [110/65] via 10.1.1.4, 00:00:45, Serial0/0
]]> OSPF – Hub & Spoke Topology https://www.expertcisco.fr/frame-relay/ospf-hub-spoke-topology Fri, 20 Apr 2012 09:08:53 +0000 http://www.expertcisco.fr/?p=420 Continue reading →]]> Dans une architecture « Hub and spoke » Frame relay, les interfaces peuvent être configurées dans 4 modes de communication OSPF :

R1(config)#int s0/0
R1(config-if)#ip ospf network ?
  broadcast       Specify OSPF broadcast multi-access network
  non-broadcast       Specify OSPF NBMA network
  point-to-multipoint Specify  OSPF point-to-multipoint network
  point-to-point      Specify OSPF point-to-point network

 

 

]]> OSPF – max-metric https://www.expertcisco.fr/ospf/ospf-max-metric Fri, 13 Apr 2012 09:03:15 +0000 http://www.expertcisco.fr/?p=416 Continue reading →]]>

Dans notre exemple, le routeur R4 peut atteindre le réseau 66.6.6.0/24 (R6) via R5 et R6 :

 

R4#show ip ospf database summary 66.6.6.0

            OSPF Router with ID (10.11.11.1) (Process ID 1)

                Summary Net Link States (Area 0)

  Routing Bit Set on this LSA
  LS age: 175
  Options: (No TOS-capability, DC, Upward)
  LS Type: Summary Links(Network)
  Link State ID: 66.6.6.0 (summary Network Number)
  Advertising Router: 10.2.2.3
  LS Seq Number: 80000011
  Checksum: 0xBC0
  Length: 28
  Network Mask: /24
        TOS: 0  Metric: 2

  Routing Bit Set on this LSA
  LS age: 215
  Options: (No TOS-capability, DC, Upward)
  LS Type: Summary Links(Network)
  Link State ID: 66.6.6.0 (summary Network Number)
  Advertising Router: 10.2.2.5
  LS Seq Number: 80000003
  Checksum: 0x1BBC
  Length: 28
  Network Mask: /24
        TOS: 0  Metric: 2

  
R4#show ip route 66.6.6.0
Routing entry for 66.6.6.0/24
  Known via "ospf 1", distance 110, metric 3, type inter area
  Last update from 10.1.1.3 on FastEthernet0/0, 00:02:36 ago
  Routing Descriptor Blocks:
  * 10.1.1.5, from 10.2.2.5, 00:02:36 ago, via FastEthernet0/0
      Route metric is 3, traffic share count is 1
    10.1.1.3, from 10.2.2.3, 00:02:36 ago, via FastEthernet0/0
      Route metric is 3, traffic share count is 1

« max-metric router-lsa » permet au routeur R5 de faire ses annonces OSPF avec un metric maximum

Configuration

R5(config)#router ospf 1
R5(config-router)#max-metric router-lsa

Vérifications:

R4#show ip ospf database summary 66.6.6.0

            OSPF Router with ID (10.11.11.1) (Process ID 1)

                Summary Net Link States (Area 0)

  Routing Bit Set on this LSA
  LS age: 241
  Options: (No TOS-capability, DC, Upward)
  LS Type: Summary Links(Network)
  Link State ID: 66.6.6.0 (summary Network Number)
  Advertising Router: 10.2.2.3
  LS Seq Number: 80000011
  Checksum: 0xBC0
  Length: 28
  Network Mask: /24
        TOS: 0  Metric: 2

  Routing Bit Set on this LSA
  LS age: 16
  Options: (No TOS-capability, DC, Upward)
  LS Type: Summary Links(Network)
  Link State ID: 66.6.6.0 (summary Network Number)
  Advertising Router: 10.2.2.5
  LS Seq Number: 80000004
  Checksum: 0xDCA
  Length: 28
  Network Mask: /24
        TOS: 0  Metric: 65536

  
R4#show ip route 66.6.6.0
Routing entry for 66.6.6.0/24
  Known via "ospf 1", distance 110, metric 3, type inter area
  Last update from 10.1.1.3 on FastEthernet0/0, 00:00:12 ago
  Routing Descriptor Blocks:
  * 10.1.1.3, from 10.2.2.3, 00:00:12 ago, via FastEthernet0/0
      Route metric is 3, traffic share count is 1
]]> OSPF Filtering https://www.expertcisco.fr/ospf/ospf-filtering Fri, 13 Apr 2012 08:45:59 +0000 http://www.expertcisco.fr/?p=412 Continue reading →]]> Plusieurs type de filtre en OSPF
  • distribute-list x in
  • area x filter-list prefix x in
  • area x filter-list prefix x out
  • distribute-list x out
  • area x.x.x.x x.x.x.x not-advertise
  • summary-address x.x.x.x x.x.x.x not-advertise

distribute-list x in

Permet de filtrer les routes OSPF (tout type) qui seront injectés (ou pas) dans la table routage locale du routeur
« distribute-list x in » n’a aucun impact sur la réception et l’annonce OSPF

Exemple:

R3#show ip route 1.1.1.0
Routing entry for 1.1.1.0/24
  Known via "ospf 1", distance 110, metric 782, type intra area
  Last update from 10.1.13.1 on Serial1/2, 00:00:04 ago
  Routing Descriptor Blocks:
  * 10.1.13.1, from 1.1.1.1, 00:00:04 ago, via Serial1/2
      Route metric is 782, traffic share count is 1

Filtre le sous réseau 1.1.1.0 /24

R3#conf t
R3(config)#access-list 1 deny 1.1.1.0 0.0.0.255
R3(config)#access-list 1 permit any

R3(config)#router ospf 1
R3(config-router)#distribute-list 1 in

Vérification:

R3#show ip route 1.1.1.0
% Network not in table

« distribute-list » peut être utilisé avec route-map et ainsi filtrer les types de routes (E1, E2), les tag … ou autres

route-map DROP-E2 deny 10
 match route-type external type-2
!
route-map DROP-E2 permit 20
!
route-map DROP-TAG-111 deny 10
 match tag 111
!
route-map DROP-TAG-111 permit 20
!
router ospf 1
 log-adjacency-changes
 network 10.1.1.4 0.0.0.0 area 0
 network 10.11.11.1 0.0.0.0 area 0
 distribute-list route-map DROP-E2 in
!

area x filter-list prefix x in

« area x filter-list prefix x in » permet de filtrer les LSA de type 3 sur un ABR
le sous réseau 11.1.1.0/24 est présent dans l’area 0 et est diffusé dans l’area 2 par l’ABR R4 (schéma plus haut)

le sous réseau 11.1.1.0/24 est donc présent dans R5 :

R5#show ip route 11.1.1.1
Routing entry for 11.1.1.0/24
  Known via "ospf 1", distance 110, metric 896, type inter area
  Last update from 10.1.45.4 on Serial0/0.54, 00:05:36 ago
  Routing Descriptor Blocks:
  * 10.1.45.4, from 4.4.4.4, 00:05:36 ago, via Serial0/0.54
      Route metric is 896, traffic share count is 1

11.1.1.0/24 est présent dans la database OSPF de l’ABR R4

R4#show ip ospf database summary 11.1.1.0

            OSPF Router with ID (4.4.4.4) (Process ID 1)

                Summary Net Link States (Area 0)

  Routing Bit Set on this LSA
  LS age: 758
  Options: (No TOS-capability, DC, Upward)
  LS Type: Summary Links(Network)
  Link State ID: 11.1.1.0 (summary Network Number)
  Advertising Router: 3.3.3.3
  LS Seq Number: 80000001
  Checksum: 0x30E2
  Length: 28
  Network Mask: /24
        TOS: 0  Metric: 782

                Summary Net Link States (Area 2)

  LS age: 14
  Options: (No TOS-capability, DC, Upward)
  LS Type: Summary Links(Network)
  Link State ID: 11.1.1.0 (summary Network Number)
  Advertising Router: 4.4.4.4
  LS Seq Number: 80000001
  Checksum: 0x8D4
  Length: 28
  Network Mask: /24
        TOS: 0  Metric: 832

Filtre du sous réseau 11.1.1.0/24

R4(config)#ip prefix-list TEST deny 11.1.1.0/24
R4(config)#ip prefix-list TEST permit 0.0.0.0/0 le 32

R4(config)#router ospf 1
R4(config-router)#area 2 filter-list prefix TEST in

Vérification:

R5#show ip route 11.1.1.1
% Network not in table

R4#show ip ospf database summary 11.1.1.0

            OSPF Router with ID (4.4.4.4) (Process ID 1)

                Summary Net Link States (Area 0)

  Routing Bit Set on this LSA
  LS age: 807
  Options: (No TOS-capability, DC, Upward)
  LS Type: Summary Links(Network)
  Link State ID: 11.1.1.0 (summary Network Number)
  Advertising Router: 3.3.3.3
  LS Seq Number: 80000001
  Checksum: 0x30E2
  Length: 28
  Network Mask: /24
        TOS: 0  Metric: 782

area x filter-list prefix x out

« area x filter-list prefix x out » permet de filtrer les annonces LSA de type 3 sur un ABR
le sous réseau 55.5.5.0/24 est présent dans l’area 2 et est diffusé dans l’area 0 par l’ABR R4 (schéma plus haut)

Table de routage de R1

R1#show ip route | inc IA
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
O IA    50.5.5.0 [110/203] via 10.1.12.2, 00:16:36, Serial0/0.12
O IA    55.5.5.0 [110/203] via 10.1.12.2, 00:16:36, Serial0/0.12
O IA    5.5.0.0 [110/203] via 10.1.12.2, 00:16:36, Serial0/0.12
O IA    10.1.45.0 [110/202] via 10.1.12.2, 00:16:36, Serial0/0.12
O IA    10.1.34.0 [110/138] via 10.1.12.2, 00:18:47, Serial0/0.12

Filtre du sous réseau 50.5.5.5.0/24

R4(config)#ip prefix-list TEST-50 deny 50.5.5.0/24
R4(config)#ip prefix-list TEST-50 permit 0.0.0.0/0 le 32

R4(config)#router ospf 1
R4(config)#area 2 filter-list prefix TEST-50 out

Vérification

R1#show ip route | inc IA
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
O IA    55.5.5.0 [110/203] via 10.1.12.2, 00:27:21, Serial0/0.12
O IA    5.5.5.0 [110/203] via 10.1.12.2, 00:07:52, Serial0/0.12
O IA    10.1.45.0 [110/202] via 10.1.12.2, 00:27:21, Serial0/0.12
O IA    10.1.34.0 [110/138] via 10.1.12.2, 00:29:32, Serial0/0.12

Autre solution, plus simple, pour ne pas annoncer un réseau :

R4(config)#router ospf 1
R4(config-router)#area 2 range 55.5.5.0 255.255.255.0 not-advertise

distribute-list x out

« distribute-list x out » est utilisé pour filtrer les LAS de type 5 ou 7 (external) sur un ABR
La commande « area x filter-list prefix » n’a aucun effet sur les routes ospf de type external

Les routeurs de de l’area 0, R3 et R4, des routes externes provenant des annonces OSPF de R5

R4#show ip route | inc E2
O E2    50.5.5.0 [110/20] via 10.1.45.5, 00:01:55, Serial0/0.45
O E2    55.5.5.0 [110/20] via 10.1.45.5, 00:01:55, Serial0/0.45
O E2    5.5.5.0 [110/20] via 10.1.45.5, 00:01:55, Serial0/0.45

R3#show ip route ospf | inc E2
O E2    50.5.5.0 [110/20] via 10.1.34.4, 00:02:16, Serial1/0.34
O E2    55.5.5.0 [110/20] via 10.1.34.4, 00:02:16, Serial1/0.34
O E2    5.5.5.0 [110/20] via 10.1.34.4, 00:02:16, Serial1/0.34

Dans le cas des routes externes, le fitre doit être placé sur le routeur en charge de la redistribution avec la commande « distribute-list x out »

Filtre du réseau externe 50.5.5.0 /24

R5(config)#access-list 1 deny 50.5.5.0 0.0.0.255
R5(config)#router ospf 1
R5(config-router)#distribute-list 1 out

Vérification

R3#show ip route ospf | inc E2
O E2    55.5.5.0 [110/20] via 10.1.34.4, 00:08:26, Serial1/0.34
O E2    5.5.5.0 [110/20] via 10.1.34.4, 00:08:26, Serial1/0.34

Autre solution, plus simple, « summary-address »

R5(config-router)#summary-address 50.5.5.5 255.255.255.0 not-advertise
]]> OSPF Area Type https://www.expertcisco.fr/ospf/ospf-area-type Fri, 13 Apr 2012 08:33:29 +0000 http://www.expertcisco.fr/?p=407 Continue reading →]]> OSPF Area Type

 

  • Stub
  • Totally Stubby
  • NSSA

 

 

Dans notre exemple :

 

Le routeur R5 annonce en OSPF 10 sous réseaux 5.5.0.0 /24 à 5.5.9.0 /24
Le routeur R1 annonce en OSPF 10 sous réseaux 1.1.0.0 /24 à 1.1.9.0 /24
Le routeur R1 redistribue dans OSPF 5 sous réseaux 10.1.0.0 à 10.1.4.0/24

Table routage de R5 (Area 2) :

R5#show ip route
Codes: C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, 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

     1.0.0.0/24 is subnetted, 10 subnets
O IA    1.1.0.0 [110/117] via 10.1.45.4, 00:00:04, FastEthernet0/0
O IA    1.1.1.0 [110/117] via 10.1.45.4, 00:00:04, FastEthernet0/0
O IA    1.1.2.0 [110/117] via 10.1.45.4, 00:00:04, FastEthernet0/0
O IA    1.1.3.0 [110/117] via 10.1.45.4, 00:00:04, FastEthernet0/0
O IA    1.1.4.0 [110/117] via 10.1.45.4, 00:00:04, FastEthernet0/0
O IA    1.1.5.0 [110/117] via 10.1.45.4, 00:00:04, FastEthernet0/0
O IA    1.1.6.0 [110/117] via 10.1.45.4, 00:00:04, FastEthernet0/0
O IA    1.1.7.0 [110/117] via 10.1.45.4, 00:00:05, FastEthernet0/0
O IA    1.1.8.0 [110/117] via 10.1.45.4, 00:00:05, FastEthernet0/0
O IA    1.1.9.0 [110/117] via 10.1.45.4, 00:00:05, FastEthernet0/0
     2.0.0.0/24 is subnetted, 1 subnets
O IA    2.2.2.0 [110/53] via 10.1.45.4, 00:00:05, FastEthernet0/0
     3.0.0.0/24 is subnetted, 1 subnets
O IA    3.3.3.0 [110/52] via 10.1.45.4, 00:00:05, FastEthernet0/0
     4.0.0.0/24 is subnetted, 1 subnets
O IA    4.4.4.0 [110/2] via 10.1.45.4, 00:00:05, FastEthernet0/0
     5.0.0.0/24 is subnetted, 10 subnets
C       5.5.0.0 is directly connected, Loopback0
C       5.5.1.0 is directly connected, Loopback1
C       5.5.2.0 is directly connected, Loopback2
C       5.5.3.0 is directly connected, Loopback3
C       5.5.4.0 is directly connected, Loopback4
C       5.5.5.0 is directly connected, Loopback5
C       5.5.6.0 is directly connected, Loopback6
C       5.5.7.0 is directly connected, Loopback7
C       5.5.8.0 is directly connected, Loopback8
C       5.5.9.0 is directly connected, Loopback9
     22.0.0.0/24 is subnetted, 1 subnets
O IA    22.2.2.0 [110/53] via 10.1.45.4, 00:00:06, FastEthernet0/0
     10.0.0.0/24 is subnetted, 9 subnets
O IA    10.1.12.0 [110/116] via 10.1.45.4, 00:00:06, FastEthernet0/0
O E2    10.1.3.0 [110/20] via 10.1.45.4, 00:00:06, FastEthernet0/0
O E2    10.1.2.0 [110/20] via 10.1.45.4, 00:00:06, FastEthernet0/0
O E2    10.1.1.0 [110/20] via 10.1.45.4, 00:00:06, FastEthernet0/0
O E2    10.1.0.0 [110/20] via 10.1.45.4, 00:00:06, FastEthernet0/0
O E2    10.1.4.0 [110/20] via 10.1.45.4, 00:00:06, FastEthernet0/0
O IA    10.1.23.0 [110/52] via 10.1.45.4, 00:00:06, FastEthernet0/0
C       10.1.45.0 is directly connected, FastEthernet0/0
O IA    10.1.34.0 [110/51] via 10.1.45.4, 00:00:06, FastEthernet0/0
     44.0.0.0/24 is subnetted, 1 subnets
O       44.4.4.0 [110/2] via 10.1.45.4, 00:00:06, FastEthernet0/0

Configuration de l’AREA 2 en STUB

  • Tous les routers de l’Area doivent être configurés avec la commande « area x stub »
  • Les LSA de type 4 et 5 (E1 et E2) ne sont plus reçus
  • Une route par défaut est injecté par l’ABR
R4#conf t
R4(config)#router ospf 1
R4(config-router)#area 2 stub

R5#conf t
R5(config)#router ospf 1
R5(config-router)#area 2 stub

Vérification :

R5#show ip route ospf
     1.0.0.0/24 is subnetted, 10 subnets
O IA    1.1.0.0 [110/117] via 10.1.45.4, 00:00:13, FastEthernet0/0
O IA    1.1.1.0 [110/117] via 10.1.45.4, 00:00:13, FastEthernet0/0
O IA    1.1.2.0 [110/117] via 10.1.45.4, 00:00:13, FastEthernet0/0
O IA    1.1.3.0 [110/117] via 10.1.45.4, 00:00:13, FastEthernet0/0
O IA    1.1.4.0 [110/117] via 10.1.45.4, 00:00:13, FastEthernet0/0
O IA    1.1.5.0 [110/117] via 10.1.45.4, 00:00:13, FastEthernet0/0
O IA    1.1.6.0 [110/117] via 10.1.45.4, 00:00:13, FastEthernet0/0
O IA    1.1.7.0 [110/117] via 10.1.45.4, 00:00:13, FastEthernet0/0
O IA    1.1.8.0 [110/117] via 10.1.45.4, 00:00:13, FastEthernet0/0
O IA    1.1.9.0 [110/117] via 10.1.45.4, 00:00:13, FastEthernet0/0
     2.0.0.0/24 is subnetted, 1 subnets
O IA    2.2.2.0 [110/53] via 10.1.45.4, 00:00:13, FastEthernet0/0
     3.0.0.0/24 is subnetted, 1 subnets
O IA    3.3.3.0 [110/52] via 10.1.45.4, 00:00:13, FastEthernet0/0
     4.0.0.0/24 is subnetted, 1 subnets
O IA    4.4.4.0 [110/2] via 10.1.45.4, 00:00:13, FastEthernet0/0
     22.0.0.0/24 is subnetted, 1 subnets
O IA    22.2.2.0 [110/53] via 10.1.45.4, 00:00:14, FastEthernet0/0
     10.0.0.0/24 is subnetted, 4 subnets
O IA    10.1.12.0 [110/116] via 10.1.45.4, 00:00:14, FastEthernet0/0
O IA    10.1.23.0 [110/52] via 10.1.45.4, 00:00:14, FastEthernet0/0
O IA    10.1.34.0 [110/51] via 10.1.45.4, 00:00:14, FastEthernet0/0
     44.0.0.0/24 is subnetted, 1 subnets
O       44.4.4.0 [110/2] via 10.1.45.4, 00:00:14, FastEthernet0/0
O*IA 0.0.0.0/0 [110/2] via 10.1.45.4, 00:00:14, FastEthernet0/0

Configuration de l’AREA 2 en « Totally Stubby »

  • L’ABR doit être configuré avec la commande « area x stub no-summary »
  • Les autres routeurs de l’Area doivent être configurés avec la commande « area x stub »
  • Les LSA de type 3, 4 et 5 ne sont plus reçus
  • Une route par défaut est injecté par l’ABR
R4#conf t
R4(config)#router ospf 1
R4(config-router)#area 2 stub no-summary

Vérification

R5#show ip route ospf
     44.0.0.0/24 is subnetted, 1 subnets
O       44.4.4.0 [110/2] via 10.1.45.4, 00:00:49, FastEthernet0/0
O*IA 0.0.0.0/0 [110/2] via 10.1.45.4, 00:00:04, FastEthernet0/0

Configuration de l’AREA 2 en « NSSA »

  • Tous les routers de l’Area doivent être configurés avec la commande « area x nssa »
  • Seuls les LSA de type 1,2,3 et 7 sont traités
  • Par défaut, en mode NSSA, aucunne route par défaut n’est injectée
R4#conf t
R4(config)#router ospf 1
R4(config-router)#area 2 nssa

R5#conf t
R5(config)#router ospf 1
R5(config-router)#area 2 nssa

Vérification

R5#show ip route ospf
     1.0.0.0/24 is subnetted, 10 subnets
O IA    1.1.0.0 [110/117] via 10.1.45.4, 00:01:12, FastEthernet0/0
O IA    1.1.1.0 [110/117] via 10.1.45.4, 00:01:12, FastEthernet0/0
O IA    1.1.2.0 [110/117] via 10.1.45.4, 00:01:12, FastEthernet0/0
O IA    1.1.3.0 [110/117] via 10.1.45.4, 00:01:12, FastEthernet0/0
O IA    1.1.4.0 [110/117] via 10.1.45.4, 00:01:12, FastEthernet0/0
O IA    1.1.5.0 [110/117] via 10.1.45.4, 00:01:12, FastEthernet0/0
O IA    1.1.6.0 [110/117] via 10.1.45.4, 00:01:12, FastEthernet0/0
O IA    1.1.7.0 [110/117] via 10.1.45.4, 00:01:12, FastEthernet0/0
O IA    1.1.8.0 [110/117] via 10.1.45.4, 00:01:12, FastEthernet0/0
O IA    1.1.9.0 [110/117] via 10.1.45.4, 00:01:12, FastEthernet0/0
     2.0.0.0/24 is subnetted, 1 subnets
O IA    2.2.2.0 [110/53] via 10.1.45.4, 00:01:12, FastEthernet0/0
     3.0.0.0/24 is subnetted, 1 subnets
O IA    3.3.3.0 [110/52] via 10.1.45.4, 00:01:12, FastEthernet0/0
     4.0.0.0/24 is subnetted, 1 subnets
O IA    4.4.4.0 [110/2] via 10.1.45.4, 00:01:12, FastEthernet0/0
     22.0.0.0/24 is subnetted, 1 subnets
O IA    22.2.2.0 [110/53] via 10.1.45.4, 00:01:13, FastEthernet0/0
     10.0.0.0/24 is subnetted, 4 subnets
O IA    10.1.12.0 [110/116] via 10.1.45.4, 00:01:13, FastEthernet0/0
O IA    10.1.23.0 [110/52] via 10.1.45.4, 00:01:13, FastEthernet0/0
O IA    10.1.34.0 [110/51] via 10.1.45.4, 00:01:13, FastEthernet0/0
     44.0.0.0/24 is subnetted, 1 subnets
O       44.4.4.0 [110/2] via 10.1.45.4, 00:01:13, FastEthernet0/0

NSSA: Injection d’une route par défaut

R4(config)#router ospf 1
R4(config-router)#area 1 nssa default-information-originate

R5#show ip route ospf | inc 0.0.0.0/0
O*N2 0.0.0.0/0 [110/1] via 10.1.45.4, 00:01:25, FastEthernet0/0

NSSA: Filtrer les LSA de type 3

R4(config)#router ospf 1
R4(config-router)#area 2 nssa no-summary

R5#show ip route ospf
     44.0.0.0/24 is subnetted, 1 subnets
O       44.4.4.0 [110/2] via 10.1.45.4, 00:13:18, FastEthernet0/0
O*IA 0.0.0.0/0 [110/2] via 10.1.45.4, 00:00:02, FastEthernet0/0

Modification du cout OSPF de la route par défaut

R4(config)#router ospf 1
R4(config-router)#area 2 default-cost 50

R5#show ip route ospf
     44.0.0.0/24 is subnetted, 1 subnets
O       44.4.4.0 [110/2] via 10.1.45.4, 00:17:21, FastEthernet0/0
O*IA 0.0.0.0/0 [110/51] via 10.1.45.4, 00:00:05, FastEthernet0/0
]]>