How to Configure OSPF Extreme Network Switch

HoIf you attended the Extreme Configuration Fundamentals course, or have experience configuring Extreme Networks products, you should be familiar with the nine steps needed to configure OSPF.
Keep in mind, with the exception of step number 2 and step number 7, most of the steps can be followed in any order. For example, you can attach physical connections last, if you wish. The main thing to remember, is that you always want to enable OSPF last. If you enable OSPF first, on a switch that is connected to an active OSPF network, there is the potential to generate LSA’s which may cause the network to reconverge unnecessarily. The nine basic steps to configure OSPF are:
1Attach the physical connections.
2Create the VLANS.
3Configure the VLAN IP address
4Add ports, tagged or untagged.
5Enable IP Forwarding.
6Configure the RouterID for each router. (Recommended)
7Create OSPF Areas as required.
Area 0.0.0.0 is already pre-configured on the switch.
8Configure the VLANs for OSPF and associate them with the correct area.
9Enable OSPF globally on the switch.
For example:
To configure the OSPF router ID, enter the following command:
configure ospf routerid [automatic | <routerid>]
If automatic is specified, the switch uses the largest IP interface address as the OSPF router ID.
To create a new OSPF area, enter the following command:
create ospf area <area identifier>
To enable OSPF for the VLANs and assign them to an area, enter the following command:
configure ospf add vlan [<vlan name> | all] area <area identifier>
To enable OSPF globally on the switch, enter the following command:
enable ospf
Here is an example OSPF configuration:
create vlan v0ospf
configure vlan v0ospf ipaddress 10.0.0.2/24
configure vlan v0ospf add ports 2,3
enable ipforwarding
configure ospf routerid 2.2.2.2
create ospf area 0.0.0.2
configure ospf add v2ospf area 0.0.0.2
enable ospf





Notes on Configuring OSPF
Each switch that is configured to run OSPF must have a unique router ID.
It is recommended that the router ID be set manually on the switc

hes participating in OSPF, instead of having the switch automatically set the router ID based on the highest interface IP address. Not performing this configuration in a larger, dynamic environments could result in an older link state database remaining in use. If a RouterID changes for a router, its LSA could stay in the LSDB for 30 minutes, corrupting the LSDB of the whole routing domain.
Virtual links are defined to connect to a specific router’s RouterID. If this changes for the target router, the virtual-link goes down, resulting in isolation of the complete area.




Verifying the OSPF Configuration
To verify which destination networks are in the routing table and the source of the routing entry, enter the following command:
show iproute
The displays shows:
●The origin of the route. (how was the route learned).
●The destination network.
●The next hop gateway.
●The type of route entry.
●The preferred route for unicast and multicast traffic.
●The duration of time this route has been in the routing table.
To verify that IP forwarding is enabled and the interface is up, enter the following command:
show ipconfig
The display shows:
●The name of each VLAN.
●The IP address of each router interface.
●If IP forwarding is enabled for each VLAN.
●If the interface is enabled and active.