Cabletron Systems TSX-1620 User Manual

Also see for SPECTRUM: User guide User guide User guide User guide Guide

Contents

Accessing the Bridge Traffic View Window3-3Using the TSX-1620 Bridge Viewthereby providing route information. The destination station directs replies toeach APE packet to the sending station, which, ideally, considers the routetraveled by the first reply received to be the most efficient route. The sendingstation then stores the route information and uses it to send subsequenttransmissions to the same station.Alternatively, a sending station may send an STE frame. On receipt of an STEpacket, a bridge can use the single bridge path as determined by the SpanningTree Algorithm to forward one Spanning Tree Explorer (STE) frame instead ofAPE frames. In response to an STE packet, the destination station sends out oneAPE packet, which returns to the sending station information on all possiblebridge paths. An STE packet is the only type of Source Route packet whose routeis determined by the Spanning Tree Algorithm. Although the Spanning TreeAlgorithm determines the bridge path an STE takes to the destination station, thebridge still uses Source Routing to forward the packet (i.e., for specifically-routedframes, the bridge will read and add information to the Routing Information Fieldin the packet’s header).Source Route Transparent BridgesA Source Route Transparent (SRT) bridge—otherwise known as a translationalbridge—functions as both a Source Route bridge and a Transparent bridge,providing all the functionality of both bridging types. Only one method, however,is used to forward any single packet.On receipt of a packet, an SRT bridge will read a packet header’s routinginformation indicator (RII) bit to determine how to forward the packet. An RII setto 1 indicates that a Routing Information Field (RIF) is present in the packet; thebridge implements Source Routing accordingly. An RII value of 0 indicates that noRIF is present in the packet; in this case, the bridge will forward the packet usingTransparent bridging. A translational bridge builds its Filtering Database frominformation it obtains from both source routed and transparently bridgedpackets.Accessing the Bridge Traffic View WindowThere are three ways to open the Bridge View: if you are working within anetwork management system, you can select the Bridge View option from theicon menu; specific directions for creating a TSX-1620 icon and accessing the iconmenu can be found in the appropriate Installing and Using SPECTRUM for...guide. If you are working within the TSX-1620 Hub View, you can select theBridge Mgmt option from the Bridge menu. If you are running in a stand-alonemode, type the following at the command line:spmarun bridge