Cabletron Systems CyberSWITCH CSX101 User's Information Manual

About the CyberSWITCH 100 Router14 CyberSWITCH 100 Advanced User InformationOperation of the CyberSWITCH 100 is influenced by routing and bridging controls and filters setduring router configuration as well as automatic spoofing and filtering performed by theCyberSWITCH 100. General IP routing, and routing or bridging from specific remote routers arecontrols set during the configuration process. Spoofing and filtering, which minimize the numberof packets across the WAN, are performed automatically by the CyberSWITCH 100. For example,RIP routing packets and certain NetBEUI packets are spoofed even if only bridging is enabled.IEEE 802.1d Bridging — The CyberSWITCH 100 supports the IEEE 802.1d standard for LANto LAN bridging. Bridging is provided over PPP as well as adjacent LAN ports. The bridgingsoftware uses transparent bridging. Configured as a bridge, the unit bridges data packets to thedestination, regardless of the network protocols used.Also included is the Spanning Tree Protocol allowing the CyberSWITCH 100 to provide bridgingredundancy while preventing data loops and duplicate data. This is a learning bridge; i.e., thebridge builds and updates an address table with each MAC source address and associatedinformation when the packets are received.IP and IPX RoutingIP Routing — IP rrouting support provides the ability to process TCP/IP frames at the networklayer for routing. IP routing support includes the Routing Information Protocol (RIP) that allowsthe exchange of routing information on a TCP/IP network. The router receives and broadcasts RIPmessages to adjacent routers and workstations. Since IP sends out periodic RIP frames that couldkeep dial-up links permanently connected, filtering and spoofing are performed to minimize thesebroadcasts on the WAN links. The router filters service packets on one end and emulates them atthe other end with spoofing. The router uses the “piggyback method” to send RIP update packetsto the WAN port. The piggyback method means that RIP update packets are sent only when thedial-up link is established because of data traffic.Network Information DiagramsIt is helpful to draw a diagram (see Figure 2 on the following page) including all locations,addresses, router names, etc. This section includes sample diagrams needed to configure theCyberSWITCH 100. You may need different addressing information depending on whether youare configuring IP routing and/or NetWare IPX routing.TCP/IP Route Addresses — If the CyberSWITCH 100 is to direct IP traffic over the ISDNconnection, the routing table in the CyberSWITCH 100 must be “seeded” with static IP routes sothat it dials out to the appropriate remote router when IP traffic is targeted to networks and stations