Cabletron Systems CyberSWITCH CSX150 User Manual

Also see for CyberSWITCH CSX150: User guide Quick start guide

Contents

USER’S GUIDE262 CyberSWITCHStatic services are configured locally on the system. SAP entries are learned from incoming SAPpackets. All services are stored, used internally and advertised to other routers.The same factors that affect the maximum number of routes stored also affect the maximumnumber of services stored. Because of these factors, the maximum number of services for eachrouter must be configurable.Each route or service entry requires memory. So increasing the number of entries may reduce theamount of memory available for other system features (such as compression). Each 1KByte ofmemory provides approximately 6 route entries or 4 service entries. If you configure the maximumnumber of table entries allowable (3072), you will consume 471 KB for the routing table, and 639KB for the service table.We recommend you size both of these tables to be at least 10% larger than their steady-state size toallow for network growth. However, you may choose a larger or smaller percentage, based onmemory availability.S PECIAL C ONSIDERATIONS - R EMOTE LAN I NTERFACEIf using a router-to-router WAN interface, the routers at both ends participate in RIP and SAPprotocols. The routers intelligently process RIP and SAP messages and can be configured to onlysend them when required. However, if using a Remote LAN interface, one end-point of theconnection is a bridge. The bridge does not understand RIP and SAP protocols; therefore, RIP/SAPmessages appear as background broadcast traffic. This traffic may cause dial-up links to remainestablished for long periods of time. For more efficient operation, consider the following whenusing a remote LAN interface:• Link utilization parameters. Most bridges and routers allow you to configure link utilizationthresholds that determine how long a dial-up connection will stay up. If your dial-up link staysup for longer than required, verify that the link utilization parameters are set properly for theconnection.• Trace facilities. Many types of background traffic can keep the dial-up connection active. Usinga trace facility or traffic analyzer, determine what type of traffic is keeping the link up. If youdetermine that RIP or SAP traffic is keeping the link up, consider the following:a. If the remote LAN has only clients, consider setting the RIP and SAP settings on theinterface to Do Not Send, Receive and Respond. These settings will allow the system toprocess the clients’ requests for servers, yet should prevent the system from keeping theconnection up unnecessarily. In addition, consider adding filters to the bridge (to preventany background traffic from devices on the remote LAN from keeping the line up), ordisable the devices’ ability to send such traffic in the first place.b. If the remote LAN has any servers or routers, the situation becomes more difficult. In suchapplications, we recommend a router-to-router WAN interface rather than a remote LANinterface. However, if you still want to use a remote LAN interface, consider adjustingthroughput monitoring parameters on both peers to drop the connection when only RIPand SAP activity is present. Or, disable RIP and SAP activity altogether and configure staticroutes and services.• If phone costs are of no concern, simply enable Send, Receive, and Respond for both RIP andSAP.