Trunk mystery

From: Hunt Lee (ciscoforme3@yahoo.com.au)
Date: Thu Mar 20 2003 - 10:16:32 GMT-3


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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This archive was generated by hypermail 2.1.4 : Sat Apr 05 2003 - 08:51:42 GMT-3