Lenovo Flex System Fabric CN4093, Application Manual

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© Copyright Lenovo 2017 Chapter 30: OSPF
485
Example 2: Virtual Links
In the example shown in Figure 52 , area 2 is not physically connected to the
backbone as is usually required. Instead, area 2 will be connected to the backbone
via a virtual link through area 1. The virtual link must be configured at each
endpoint.
Figure 52.
Configuring a Virtual Link
Note:
OSPFv2 supports IPv4 only. IPv6 is supported in OSPFv3 (see “OSPFv3
Implementation in Enterprise NOS” on page 491 ).
Configuring OSPF for a Virtual Link on Switch #1
1.
Configure IP interfaces on each network that will be attached to the switch.
In this example, two IP interfaces are needed:
 Interface 1 for the backbone network on 10.10.7.0/24
 Interface 2 for the transit area network on 10.10.12.0/24
2.
Configure the router ID.
A router ID is required when configuring virtual links. Later, when configuring the
other end of the virtual link on Switch 2, the router ID specified here will be used as
the target virtual neighbor (
nbr
) address.
3.
Enable OSPF.
4.
Define the backbone.
BladeCenter
IF 1
10.10.7.1
IF 2
10.10.12.1
IF 1
10.10.12.2
IF 1
10.10.24.1
Backbone Transit Area Stub Area
Application
Switch 1 Switch 2
Area 0
(0.0.0.0)
Area 1
(0.0.0.1)
Area 2
(0.0.0.2)
Virtual Link 1
10.10.12.0/24
Network
10.10.7.0/24
Network
10.10.24.0/24
Network
Router ID:
10.10.10.1
Router ID:
10.10.14.1
CN 4093(config)# interface ip 1
CN 4093(config-ip-if)# ip address 10.10.7.1 255.255.255.0 enable
CN 4093(config-ip-if)# exit
CN 4093(config)# interface ip 2
CN 4093(config-ip-if)# ip address 10.10.12.1 255.255.255.0 enable
CN 4093(config-ip-if)# exit
CN 4093(config)# ip router-id 10.10.10.1
CN 4093(config)# router ospf
CN 4093(config-router-ospf)# enable
CN 4093(config-router-ospf)# area 0 area-id 0.0.0.0
CN 4093(config-router-ospf)# area 0 type transit
CN 4093(config-router-ospf)# area 0 enable