From: Jonathan V Hays (jhays@jtan.com)
Date: Thu Mar 20 2003 - 14:15:02 GMT-3
In fact, if you use the OSPF router-id command, you not only do not need
a route, the router-id does not have to be an IP address configured on
the router. You can just invent an address for the router-id command.
It's just a label.
Now, making up an address may have other consequences...
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
> Behalf Of OhioHondo
> Sent: Thursday, March 20, 2003 9:43 AM
> To: Hunt Lee; ccielab@groupstudy.com
> Subject: RE: Trunk mystery
>
>
> Hunt
>
> The Virtual Link statement uses OSPF Router-ID's, not IP
> addresses. Router's R1 and R2 have to make an OSPF neighbor
> adjacency for area 2 over VLAN 30 before the Virtual Link
> will work. If this adjacency is made, Router 1 will see it
> has an OSPF adjacency with OSPF router-id 200.200.200.1.
> Router 2 will see it has an OSPF neighbor adjacency with OSPF
> router-id 11.1.1.1. That's all they need to know to establish
> the virtual link. Router 1 has OSPF Area 11. Router 2 needs
> to have a presence of OSPF area 0. (Which they both do.)
>
> You do not need the default route to establish this virtual link.
>
> If you're troubleshooting, make sure that you have the Area 2
> OSPF neighbor adjacency and that the routers are reporting
> the router-id's that you expect.
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On
> Behalf Of Hunt Lee
> Sent: Thursday, March 20, 2003 8:17 AM
> To: ccielab@groupstudy.com
> Subject: Trunk mystery
>
>
> Hi group,
>
> I'm confused on the following eg.
>
> <--- Area 2 ----->
>
> Trunk VLAN30
> 11.1.1.1---R1 --- Cat 3550 ---- R2---200.200.200.1
> (Area 11) |
> |
> |
> other OSPF routers (OSPF Area 0)
>
> R2 is advertising a default route out to OSPF
> by: ip route 0.0.0.0 0.0.0.0 137.20.20.2
>
> Both 11.1.1.1 & 200.200.200.1 are Loopback interface by R1
> and R2 respectively
>
> I scratched my head as to how can R2 establish a virtual-link
> to R1 with IP 11.1.1.1, where 11.1.1.1 is in Area 11, since I
> was expecting that R2 won't be able to know about 11.1.1.1
> until the Virtual-Link is formed...
>
> At R2:-
>
> interface Loopback0
> ip address 200.200.200.1 255.255.255.0
>
> interface Ethernet0
> ip address 137.20.20.1 255.255.255.0
> ip ospf priority 200
>
> router ospf 1
> router-id 200.200.200.1
> log-adjacency-changes
> area 2 virtual-link 11.1.1.1 <---- How can R2 see 11.1.1.1
> network 137.20.20.1 0.0.0.0 area 2
> network 150.100.32.2 0.0.0.0 area 0
> default-information originate metric 100 metric-type 1
>
> At R1:-
>
> interface Loopback0
> ip address 11.1.1.1 255.255.255.0
>
> interface FastEthernet0/0.1
> encapsulation dot1Q 10
> ip address 192.168.1.11 255.255.255.224
> !
> interface FastEthernet0/0.2
> encapsulation dot1Q 20
> ip address 10.90.1.11 255.255.255.0
> !
> interface FastEthernet0/0.3
> encapsulation dot1Q 30
> ip address 137.20.20.11 255.255.255.0
> !
> router ospf 1
> router-id 11.1.1.1
> log-adjacency-changes
> area 2 virtual-link 200.200.200.1
> summary-address 192.168.1.0 255.255.255.0
> network 11.1.1.1 0.0.0.0 area 11
> network 137.20.20.11 0.0.0.0 area 2
>
>
> And at 3550:-
>
> interface FastEthernet0/2
> description R2
> switchport access vlan 30
> switchport mode access
> no ip address
>
> interface FastEthernet0/14
> description R1's Trunk port
> switchport trunk encapsulation dot1q
> switchport trunk allowed vlan 1-39,184-4094
> switchport mode trunk
> no ip address
> duplex full
> speed 100
>
> Regards,
> Lee
>
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