Cabletron Systems HSIM-W6 Installation Manual

Also see for CyberSWITCH HSIM-W6: Setup guide Configuration guide User guide User guide

Contents

HSIM-W6 Firmware SupportHSIM-W6 Installation Guide2-13OSPF, based upon link-state technology, was developed by the Internet Engineering Task Force(IETF). The IETF developed OSPF based upon the shortest path first algorithm to serve large,heterogeneous networks.A key feature of OSPF is the speed in which it responds to topological changes, commonlyreferred to as “convergence time.” OSPF generates a minimal amount of routing protocol trafficcompared to most distance vector protocols.Cabletron’s implementation of OSPF is based on RFC 1247 — OSPF Version 2 and RFC 1253 —OSPF Version 2 Management Information Base.IP-OSPF HierarchyIP-OSPF operates within a hierarchy of entities:Autonomous SystemAn Autonomous System (AS) is a set of routers and networks under a common administration.Routers inside an AS are called “interior gateways” and the protocol is called Interior GatewayProtocol (IGP). OSPF is an IGP.Every OSPF routing domain must have a backbone. An OSPF backbone distributes routinginformation between areas in an OSPF routing domain. The backbone of an OSPF routing domainsystem is an OSPF area possessing an area id of 0.0.0.0.AreasAreas are groups of networks and attached hosts. A router’s topology database includes area links,and summarized and external links depicting the autonomous system topology. From thisdatabase, routers calculate a route using the shortest-path tree algorithm.The Hello ProtocolThe Hello Protocol establishes and maintains neighbor relationships, and ensures bidirectionalcommunications among neighboring routers. Hello packets are sent out all router portsperiodically. A designated router is chosen by the Hello Protocol on multi-access networks andcontrols adjacencies formed over the network.Neighbors and AdjacencyThe OSPF routing protocol establishes adjacencies among neighboring routers which facilitate theexchange of routing information. Neighboring routers have interfaces to a common network andare discovered by OSPF’s Hello Protocol.