Nortel Networks NN47200-503 manual Ospf Enhancements, Host route in LSA

30An Introduction to IP Routing Protocols

Host routes are managed with Nortel Networks Command Line Interface (NNCLI) commands and SNMP MIBs and are identified by the host IP address and the configured route type of service (TOS). For each host directly connected to the router, configure the cost of the link to the host during host creation. You cannot modify this cost.

Note: Always set TOS to 0 because TOS-based routing is not supported.

When a host is added to, or deleted from, a host route, the router updates the router LSAs and floods them to neighbors in each area where that router has an interface.

Following is an example of parameters for a host route advertised in the LSA.

Host route in LSA

•Type: 3 (stub network)

•LinkID: IP address of host directly connected to router

•Link Data: 0xFFFFFFFF

•Metric: configured cost of host

OSPF Enhancements

•Host route - Allows a router to advertise to its neighbors all hosts that are directly attached to that router’s interfaces. Up to 32 host routes can be configured.

•Virtual links - The OSPF network can be partitioned into multiple areas. However, a backbone area must exist and be contiguous, and every non-backbone area must be connected to the backbone area using either a physical or a logical link. In a network where a physical connection between the non-backbone area and backbone area is impossible, use of a virtual link provides the logical connection through another non-backbone area, called the transit area. Virtual links can be created manually or automatically. The 5500 Series switch supports up to 16 virtual links.

When 5500 Series switches are stacked, and a unit leaves the stack and becomes standalone, the router ID is automatically changed to its default value if IP blocking is turned off and OSPF is globally enabled. This prevents duplication of a router ID in the OSPF routing domain. The new router ID value is temporary, that is, it is not saved to NVRAM. Therefore, upon reset, the old router ID is restored. Configurable using NNCLI, ACG, and Device Manager.

Example configurations The following is an example for creating a host route:

Nortel Ethernet Routing Switch 5500 Series

Configuration-IP Routing Protocols

NN47200-503 03.01 Standard

5.127 August 2007

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