Cabletron Systems SmartSTACK ELS100-S24TX2M User Manual

Also see for SmartSTACK ELS100-S24TX2M: Quick installation guide Quick installation guide Management guide

Contents

9033260-01 Product Overview 11Flow ControlFlow control allows you to manage network traffic during congestionperiods and to prevent the loss of packets when port buffer thresholds areexceeded. Flow control also serves to deny access to additional trafficthat could add to a congestion condition. The ELS100-S24TX2M switchsupports flow control per the IEEE 802.3x standard. Note that flow controlis disabled on all ports by default but can be enabled on a per-port basisby using the console interface menus, the on-board Web agent, or viaSNMP. See Appendix B, “Flow Control,” for more information on thisfeature.Virtual LANs (VLANs)VLANs allow you to connect users to a specific LAN segment regardlessof their physical location. The ELS100-S24TX2M switch supports taggedVLANs per the IEEE 802.1Q draft standard. With frame tagging, a shorttag is appended to every frame that crosses the network backbone. Thetag identifies which VLAN the frame belongs to. See Appendix B, “VirtualLANs,” in the Management Guide for more information.Class of ServiceClass of Service support allows you to assign a higher priority to selectedtraffic passing through the switch. The ELS100-S24TX2M switchsupports Class of Service attributes per the IEEE 802.1p standard usinga priority queuing mechanism. This feature ensures that traffic duringcongestion periods will not interfere with traffic assigned a higher priority.Traffic assigned a lower priority is subject to discard when memory is inshort supply. See Appendix C, “Class of Service,” in the ManagementGuide for more information.Port TrunkingPort trunking allows you to combine ports into an aggregate connectionbetween ELS100-S24TX2M switches. Besides balancing the load acrosseach port in the trunk, the additional ports provide redundancy by takingover the load if a port in the trunk should fail. The ELS100-S24TX2Mallows up to four RJ-45 ports from a pre-determined selection of ports tobe joined together as a trunk. Up to three port trunks on a singleELS100-S24TX2M switch, or 12 for an entire stack, can be configured.Note that ports cannot be configured into a trunk across switches in astack.If flow control is desired for one port, it is r ecomm ended thatit be enabled on all ports. However, note that flow contr olshould not be used if a port is connected to a hub. Also, beaware that when interconnecting high-speed LANs (such asGigabit Ethernet) and low-speed LANs, flow control can causetraffic from the high-speed LAN to be blocked for all otherports on the switch.