Administration of the Avaya G350 Media Gateway - Avaya Support

Configuring OSPFIn OSPF, routers use link-state updates to send routing information to all nodes in a network bycalculating the shortest path to each node. This calculation is based on a topography of thenetwork constructed by each node. Each router sends that portion of the routing table thatdescribes the state of its own links, and it also sends the complete routing structure(topography).You can configure route redistribution between OSPF, RIP, and static routes. With routeredistribution, you can configure the G350 to redistribute routes learned from one protocol intothe domain of the other routing protocol. For more information, see Route redistribution onpage 197.OSPF dynamic costAn OSPF interface on the G350 can dynamically set a Cost. The Cost represents the priceassigned to each interface for purposes of determining the shortest path.By default the OSPF interface Cost is calculated based on the interface bandwidth, according tothe following formula:Cost = 100,000/bandwidth (in kbps)The result is that the higher the bandwidth, the lower the Cost.To manually configure the Cost of an OSPF interface, use the ip ospf cost command fromthe interface context. By using this option, dynamic bandwidth updates do not change the Cost.Use the no ip ospf cost command to return to dynamic cost calculation on an interface.Use the bandwidth command from the Interface context to manually adjust the interface’sbandwidth If Cost is being determined dynamically, this configured bandwidth and not the actualinterface bandwidth, is used to calculate Cost.OSPF limitationsYou can configure the G350 as an OSPF Autonomous System Boundary Router (ASBR) usingroute redistribution. The G350 can be installed in the OSPF backbone area (area 0.0.0.0) or inany OSPF area that is part of a multiple areas network. However, the G350 cannot beconfigured to be an OSPF area border router itself.The G350 supports the ECMP equal-cost multipath (ECMP) feature which allows loadbalancing by splitting traffic between several equivalent paths.While you can activate OSPF with default values for each interface using a single command,you can configure many of the OSPF parameters.Issue 3 January 2005 195