3Com 4210, 5500G, 4200G Virtual Link, This case, configuring Ospf virtual links is a solution

126CHAPTER 15: ROUTING CONFIGURATION GUIDE

Configuring OSPF	Among OSPF areas in an AS, one area is different from any other area. Its area ID is
Virtual Link	0 and it is usually called the backbone area. The backbone area is responsible for
	distributing routing information between none-backbone areas. Therefore, OSPF
	requires that:
	■ All non-backbone areas must maintain connectivity to the backbone area.
	■ The backbone area must maintain connectivity within itself.
	In practice, the requirements may not be satisfied due to physical limitations. In
	this case, configuring OSPF virtual links is a solution.
	A virtual link is established between two ABRs through a non-backbone area and
	is configured on both ABRs to take effect. The non-backbone area is a transit area.
Network Diagram	Figure 34	Networking diagram for OSPF virtual link
	Switch A	Area 1		Switch B
		Vlan-int2
		Virtual link
	Vlan-int1		Vlan-int1
	Area 0			Area 2
	Device	Interface		IP address	Router ID
	Switch A	Vlan-int1	196.1.1.2/24		1.1.1.1
		Vlan-int2	197.1.1.2/24		-
	Switch B	Vlan-int1	152.1.1.1/24		2.2.2.2
		Vlan-int2	197.1.1.1/24		-

Networking and Configure OSPF in the network, which is divided into three areas: the backbone Configuration area and two non-backbone areas (Area 1 and Area 2). Area 2 has no direct Requirements connection to the backbone area; the connection from Area 2 to the backbone

area must go through Area 1. The user hopes to enable Area 2 to communicate with the other two areas.

Based on the user requirements and network environment, configure a virtual link to connect Area 2 to the backbone area.

Applicable Products

Product series	Software version	Hardware version
Switch 5500	Release V03.02.04	All versions
Switch 5500G	Release V03.02.04	All versions
Switch 4500	Release V03.03.00	All versions