06-25-2003 02:09 AM
I've been told by one sneaky CCIE that instead of configuring each network of the router to run OSPF there is one command "network x.x.x.x 255.255.255.255 area 0" to activate it on all interfaces. What should I enter instead of x.x.x.x?
Thanks.
06-25-2003 04:19 AM
If you set x.x.x.x to 0.0.0.0 ("all zeros") then the inverse mask 255.255.255.255 will match any IP address you assign to an interface. This will activate OSPF for that interface, and put it in area 0.
06-28-2003 03:26 AM
I've always use network 0.0.0.0 0.0.0.0 area x, and it works.... This also works with eigrp, just in case you're interested.
:-)
Russ.W
06-28-2003 05:14 AM
Thanks, Russ.
If you have time please take a look on OSPF config below. Any ideas why is it so?? I marked my questions with *************(somewhere toward the middle of the config file)
------------------------------------
Upper#sh run
Building configuration...
Current configuration : 911 bytes
!
version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
service udp-small-servers
service tcp-small-servers
!
hostname Upper
!
logging queue-limit 100
enable password cisco
!
ip subnet-zero
!
interface Ethernet0
ip address 10.10.2.2 255.255.255.0
no ip route-cache
no ip mroute-cache
!
interface Serial0
bandwidth 64000
ip address 10.10.10.2 255.255.255.0
no ip route-cache
no ip mroute-cache
!
interface Serial1
no ip address
no ip route-cache
no ip mroute-cache
shutdown
!
router ospf 1
log-adjacency-changes
network 10.10.1.0 0.0.0.255 area 0
network 10.10.10.0 0.0.0.255 area 0
!
router rip
network 10.0.0.0
!
ip classless
no ip http server
!
line con 0
line aux 0
transport input all
line vty 0 4
password cisco
login
!
end
Upper#sh ip ospf int
Serial0 is up, line protocol is up
Internet Address 10.10.10.2/24, Area 0
Process ID 1, Router ID 10.10.10.2, Network Type POINT_TO_POINT, Cost: 1
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:02
Index 1/1, 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 10.10.10.1
Suppress hello for 0 neighbor(s)
!
Upper#sh ip ospf database
OSPF Router with ID (10.10.10.2) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
10.10.10.1 10.10.10.1 133 0x80000002 0x00A7AF 3
10.10.10.2 10.10.10.2 135 0x80000007 0x00BEC0 2
!
Upper#sh ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
10.10.10.1 1 FULL/ - 00:00:35 10.10.10.1 Serial0
Upper#sh ip route ospf
10.0.0.0/24 is subnetted, 2 subnets
O 10.10.1.0 [110/11] via 10.10.10.1, 00:02:40, Serial0
!
Upper#sh ip ospf
Routing Process "ospf 1" with ID 10.10.10.2
Supports only single TOS(TOS0) routes
Supports opaque LSA
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
Number of external LSA 0. Checksum Sum 0x000000
Number of opaque AS LSA 0. Checksum Sum 0x000000
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
External flood list length 0
Area BACKBONE(0)
Number of interfaces in this area is 1
Area has no authentication
SPF algorithm executed 7 times
Area ranges are
Number of LSA 2. Checksum Sum 0x01666F
Number of opaque link LSA 0. Checksum Sum 0x000000
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 0
Flood list length 0
Upper#sh 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
10.0.0.0/24 is subnetted, 2 subnets
O 10.10.1.0 [110/11] via 10.10.10.1, 00:03:08, Serial0
C 10.10.10.0 is directly connected, Serial0
!
Upper#10.10.10.1
Trying 10.10.10.1 ... Open
In vino veritas
User Access Verification
Password:
Lower>sh 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
---------------------------------
10.0.0.0/24 is subnetted, 2 subnets
C 10.10.1.0 is directly connected, Ethernet0
C 10.10.10.0 is directly connected, Serial0
************ why I dont see OSPF route here????
----------------------------
Lower>sh ip ospf database
OSPF Router with ID (10.10.10.1) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
10.10.10.1 10.10.10.1 318 0x80000002 0x00A7AF 3
10.10.10.2 10.10.10.2 321 0x80000007 0x00BEC0 2
Lower>enable
Password:
Lower#sh run
Building configuration...
Current configuration : 1006 bytes
!
version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
service udp-small-servers
service tcp-small-servers
!
hostname Lower
!
logging queue-limit 100
enable password cisco
!
ip subnet-zero
!
interface Ethernet0
ip address 10.10.1.1 255.255.255.0
no ip route-cache
no ip mroute-cache
no keepalive
!
interface Serial0
bandwidth 64000
ip address 10.10.10.1 255.255.255.0
no ip route-cache
no ip mroute-cache
no fair-queue
clockrate 64000
!
interface Serial1
no ip address
no ip route-cache
no ip mroute-cache
shutdown
!
interface BRI0
no ip address
encapsulation hdlc
no ip route-cache
no ip mroute-cache
shutdown
!
router eigrp 1
network 10.0.0.0
auto-summary
!
router ospf 1
log-adjacency-changes
network 0.0.0.0 255.255.255.255 area 0
!
router rip
network 10.0.0.0
!
ip classless
no ip http server
!
!
banner motd ^C In vino veritas ^C
!
line con 0
line aux 0
transport input all
line vty 0 4
password cisco
login
!
end
Lower#sh ip ospf int
Serial0 is up, line protocol is up
Internet Address 10.10.10.1/24, Area 0
Process ID 1, Router ID 10.10.10.1, Network Type POINT_TO_POINT, Cost: 1
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:01
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 10.10.10.2
Suppress hello for 0 neighbor(s)
Ethernet0 is up, line protocol is up
Internet Address 10.10.1.1/24, Area 0
Process ID 1, Router ID 10.10.10.1, Network Type BROADCAST, Cost: 10
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 10.10.10.1, Interface address 10.10.1.1
No backup designated router on this network
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:01
Index 1/1, 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)
Lower#sh ip ospf
Routing Process "ospf 1" with ID 10.10.10.1
Supports only single TOS(TOS0) routes
Supports opaque LSA
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
Number of external LSA 0. Checksum Sum 0x000000
Number of opaque AS LSA 0. Checksum Sum 0x000000
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
External flood list length 0
Area BACKBONE(0)
Number of interfaces in this area is 2 why is it 2 interfaces here???
Area has no authentication
SPF algorithm executed 2 times
Area ranges are
Number of LSA 2. Checksum Sum 0x01666F
Number of opaque link LSA 0. Checksum Sum 0x000000
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 0
Flood list length 0
Lower#
06-28-2003 10:22 AM
Joseph,
Your Ethernet and serial interfaces are directly connected to those IP subnets, so they are listed as "C" for connected. They are the most direct paths for your router to those networks.
When you run "router ospf x" and specify networks under that, you are enabling your router interfaces on those networks to send and receive OSPF route information and updates over those interfaces. If your router were to hear of a network that it's not directly connected to from another router (for example, your 10.10.10.2 router), then the route would show up as an "O" in the route table.
If your router hears via OSPF about a route to one of the networks it is directly connected to, the directly-connected one is what will show in the route table since it's the lowest-cost path. You would see the OSPF route only if it was equal in cost (in which case you would see each equal-cost path in the routing table) or lower in cost (in which case you would see just the OSPF route). But an OSPF-learned route will never be equal to or lower in cost than a direct connection.
Hope this helps.
06-28-2003 01:16 PM
Larry,
I understand your logic. But you perhapse overlooked the fact, that in one of the routers ('Upper') "sh ip route" command shows OSPF route. Do you know why? Routers config are the same (except of course IP addresses)
Joseph
06-29-2003 12:57 AM
Sorry, I just did a search down the listing to where the *****'s were.
Your "Upper" router sits on an Ethernet with 10.10.2.0 subnet, and serial with 10.10.10.0 subnet. OSPF is enabled for "Upper"'s interfaces on the 10.10.10.0 subnet, so it learns about the indirectly connected network 10.10.1.0 from the "Lower" router.
But OSPF is NOT enabled for "Upper"'s interface on the 10.10.2.0 subnet, so it doesn't advertise that subnet to "Lower" over the serial link. Also, it appears that "Upper"'s Ethernet connection on the 10.10.2.0 subnet may be down, since the route didn't show up as a direct-connected network when you executed "show ip route".
Change the "network 10.10.1.0 0.0.0.255 area 0" on "Upper" to "network 10.10.2.0 0.0.0.255 area 0" and make sure the Ethernet port is connected and up, and "Upper" will start advertising the route over the serial connection. "Lower" should learn it pretty quickly when you make the change.
OSPF must be enabled for the subnet that an interface is on, in order for that interface to send and receive OSPF updates. In addition to learning and advertising routes on that port, information about that direct-connected route (and all indirect routes learned through it) will also be advertised out all other OSPF-enabled ports on the router. But only when that link is up. If it starts out down, then the routes don't get advertised; and if it was up but subsequently went down, then link state change advertisements go out all other OSPF-enabled ports, notifying other routers of the change.
I think this is the information you're looking for.
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