Cabletron Systems TRFMIM 28 TRFMIM-28 User Manual

Also see for SmartSwitch 9000: Reference guide Appendix Appendix Appendix User guide

3-3OperationSmartSwitch ASICThe SmartSwitch ASIC is a hardware-based switch design that is the key buildingblock of the SmartSwitch 9000 hub. The SmartSwitch ASIC makes all filtering/forwarding decisions in custom hardware as opposed to software, as intraditional bridges. This custom hardware enables the SmartSwitch ASIC toprocess over 750K frames per second. The SmartSwitch ASIC is designed tosupport up to 64 ports shared between the host processor, the INB backplane, andLAN/WAN interfaces on the front panel of SmartSwitch 9000 modules. TheSmartSwitch ASIC can operate in two modes: as a traditional switch or as aSecureFast Switch (SFS).Traditional SwitchWhen operating as a traditional switch, the SmartSwitch ASIC makes filtering/forwarding decisions based on Destination Address (DA), with standard IEEE802.1d learning.VLANModules within a MMAC chassis utilize connection-oriented SecureFast Switches(SFS) to create Virtual LANs, or VLANs.A VLAN is a local area network of endpoints having full connectivity (sharingbroadcast, multicast, and unicast packets) independent of any particular physicalor geographical location. In other words, endpoints that share a virtual LANappear to be on a single LAN segment regardless of their actual location. Changesto VLANs, (e.g., moving nodes) are accomplished via software, reducing networkmanagement time and expense.VLANs extend direct communication between users beyond the constraints of aphysical LAN segment by allowing the establishment of VLANs that encompassusers on multiple physical LAN segments. This permits endpoints to beadministratively grouped. For example, in Figure 3-2, the users on LANs A and Bbelong to the Finance group, however, they are physically removed from eachother and as such cannot communicate directly. The VLAN solution places bothLAN segments on the same VLAN; all endpoints appear and act as if they are onthe same physical LAN.Most VLAN implementations require a router for Inter-VLAN communication;Cabletron’s SecureFast VLAN operational model does not. Inter-VLANcommunication is accomplished via multi-layer switches or optional traditionalrouter.