The goal of this guide is to provide guidance for implementing OSPF on the 128T Networking Platform. The OSPF feature enables a dynamic and flexible integration of SVR in customer networks. Open Shortest Path First (OSPF) is an interior gateway protocol (IGP) that is most often used to dynamically manage network routes in large enterprise network. It determines routes dynamically by obtaining information from other routers and advertising routes to other routers by way of Link State Advertisements (LSAs). The information gathered from the LSAs is used to construct a topology map of the network. This topology map is shared across routers in the network and used to populate the IP routing table with available routes.
Learning routes from OSPF simplifies enterprise configuration and integration with Secure Vector Routing.
This document presumes that the reader has a running 128T system and wants to add configuration to support OSPF. The running 128T system includes configuration for basic platform functionality (e.g., router, node, device-interface, network-interface) and basic routing configuration (e.g., tenants, services, etc.).
As with BGP and static routes, the OSPF configuration exists within the routing configuration container in the 128T data model. First, we’ll configure the OSPF “instance” and give it the instance-id of 1.
Next we’ll configure a router-id. Typically, the highest router-id on the network becomes the designated router for the network.
Next we’ll configure an OSPF area and put interfaces into that area. The area is in the format x.x.x.x; for example, area 0 is configured as 0.0.0.0. Interfaces, as they are in other areas of the system, require the node name that contains the interface and the interface’s name.
If adding an interface that is part of a highly available set (e.g., they share the same MAC address and global ID), it is important that you only add one of the interfaces into the area. This will be sufficient to achieve high availability, as the 128T software will map the “shared” interface into the area.
Next, we can optionally elect to have the 128T redistribute connected routes, static routes, BGP routes, or service routes into OSPF. This is done with one or more “redistribute” elements within the OSPF instance. (Within each of these redistribute elements you can specify metrics, metric-type, and policies to apply to the redistributed routes.)
To enable service routing (service-route elements) to leverage the learned routes that a 128T has exchanged via OSPF (or any routing protocol), the “use-learned-routes” selector should be enabled in the appropriate service-route configuration.
Several “show” commands are available in the PCLI to display information about the state of the OSP protocol. In addition to the “show ospf” branch of output, you will now see contributions to the RIB from OSPF in the output of “show rib”.
OSPF Troubleshooting Steps
- Verify OSPF router information (show ospf detail or show ospf summary)
- Check the area
- Check for adjacency
- Verify OSPF interface ( show ospf interface)
- Verify OSPF neighbors (show ospf neighbors)
- Check state FULL for each neighbor
- Verify which router is the designated router
- Verify RIB (show rib or show ospf routes)
- Routes beginning with O are OSPF routes
- Verify FIB ( show fib)
- FIB entry has the appropriate next hop