Dell PowerConnect 6248 User's Guide - Page 549

The OSPF Route Redistribution Summary page contains the following fields: • Source - The Source Route to be redistributed by OSPF. • Redistribute - Specify whether to allow the routes learned through this protocol to be redistributed. • Metric - The Metric of redistributed routes for the given Source Route. Displays 0 when not configured. • Metric Type - The OSPF metric type of redistributed routes. • Tag - The tag field in routes redistributed. This field displays the tag value if the source was preconfigured, otherwise 0 is displayed. • Subnets - Specify whether the subnetted routes should be redistributed (Enable) or not (Disable). • Distribute List - The access list that filters the routes to be redistributed by the destination protocol. Displays 0 when not configured. • Redistribute - Redistribute among other VLANs in the domain. Displaying the Route Redistribution Summary Using CLI Commands For information about the CLI command that performs this function, see the following chapter in the CLI Reference Guide: • OSPF Commands The following table summarizes the equivalent CLI commands for this feature. Table 9-18. OSPF Route Redistribution Summary Command CLI Command show ip ospf Description Displays OSPF route redistribution summary data. Nonstop Forwarding OSPF Graceful Restart The OSPF protocol can be configured to perform a "graceful restart" in conjunction with the nonstop forwarding feature (see "Nonstop Forwarding" on page 258) for stacked switches. When OSPF graceful restart is enabled and the management unit in a stack fails, the hardware can continue to forward packets using OSPF routes while a backup switch takes over management unit responsibility. Graceful restart uses the concept of "helpful neighbors". A fully adjacent router enters helper mode when it receives a link state announcement (LSA) from the restarting management unit indicating its intention of performing a graceful restart. In helper mode, a switch continues to advertise to the rest of the network that they have full adjacencies with the restarting router, thereby avoiding announcement of a topology change and and the potential for flooding of LSAs and shortest-path-first (SPF) runs (which determine OSPF routes). Helpful neighbors continue to forward packets through the restarting router. The restarting router relearns the network topology from its helpful neighbors. Graceful restart can be enabled for either planned or unplanned restarts, or both. A planned restart is initiated by the operator (see "Enabling and Disabling NSF" on page 258). The operator may initiate a failover in order to take the management unit out of service (for example, to address a partial hardware Configuring Routing 549