Cabletron Systems CSX200 CyberSWITCH Installation Manual

Also see for CSX200 CyberSWITCH: Setup guide User guide Configuration guide User guide

Contents

Chapter 2: About the CSX2002-10CSX200 Installation GuideIn transparent bridging, the decision to forward the frame is based on this comparison. If theaddress indicates that the sending station and the destination station are on the same side of thebridge, the frame is not forwarded across the bridge. If the addresses do not indicate that, thebridge forwards the broadcast frame across the bridge to the other network(s).Bridging allows frames to be sent to all destinations regardless of the network protocols used. Italso allows protocols that cannot be routed (such as NETBIOS) to be forwarded, and optimizesinternetwork capacity by localizing traffic on LAN segments. A bridge extends the physical reachof networks beyond the limits of each LAN segment. Filters can be used to increase networksecurity in bridged networks, and restrict message forwarding by using user-built addresstables (non-transparent bridging).Routing — Routing provides a way to transfer user data from source to destination over differentLAN and WAN links using one or more network protocol formats. Routing relies on routingaddress tables to determine the best path for each packet. Routing tables can be seeded (i.e.,addresses for remote destinations are placed in the table along with network address masks and ametric for path latency). Routing tables are also built dynamically (i.e., the location of remotestations, hosts and networks are updated through inter-router protocols). Routing helps to increasenetwork capacity by localizing traffic on LAN segments and broadcasts that would result frombridged traffic. It also provides security by isolating traffic on segmented LANs. Routing extendsthe world-wide reach of networks.CSX200 Bridging and Routing — The CSX200 can operate as a bridge, a router, or both. TheCSX200 operates as a router for network protocols that are supported when routing is enabled andoperates as a bridge when bridging is enabled. When both bridging and routing are enabled,routing takes precedence over bridging; i.e., the CSX200 uses the protocol address information ofthe packet to route the packet to the correct destination. However, if the protocol is not supported,the CSX200 operates as a bridge and uses the MAC address information to send the packet.Operation of the CSX200 is influenced by routing and bridging controls and filters set duringCSX200 configuration. General IP routing, and routing or bridging from specific remote routersare controls set during the configuration process.IEEE 802.1d Bridging — The CSX200 supports the IEEE 802.1d standard for LAN to LANbridging. Bridging is provided over PPP and Frame Relay as well as adjacent LAN ports. Bridginguses the MAC (Machine Address and Control layer) address unique to each device. Whenconfigured as a bridge, the CSX200 bridges data packets to the destination, regardless of thenetwork protocols used.