IBM SG24-4817-00 manual This soft copy for use by IBM employees only

This soft copy for use by IBM employees only.

−Support port mirroring (TokenProbe or Etherprobe) whereby one port can monitor any LAN port for the purposes of connecting a LAN analysis tool

−Support three switching modes to optimize performance:

1.Cut-Through Switching

In this mode, the switch reads in the address portion of the frame header, makes a forwarding decision strictly based on destination address, and forwards the header and the remainder of the packet to the destination port while the packet is still arriving. This optimizes forwarding performance, but does not filter out bad frames.

2. Store-and-Forward Switching

In this mode, the switch reads the entire packet into a buffer and performs a full CRC check on it before forwarding good packets to the destination port. This eliminates bad frames, but with a greater latency.

3. Adaptive Switching

This feature allows the switch to run in cut-through mode (for high performance and low latency) until the number of bad packets received surpasses a user-settable threshold within a given period of time. It then automatically switches to store-and-forward mode to avoid propagating bad packets. When the number of bad packets falls to acceptable levels, the switch reverts automatically to

cut-through mode. The net result is to give the highest possible performance with the least number of errors.

−Provides a Virtual Switch capability that allows the switch to operate as though it were actually several (up to 8) switches. That is to say, traffic arriving on a port can only be forwarded to ports within its group. This also means that broadcasts are isolated within each virtual switch.

−Support inbound MAC address filtering which allows:

-Blocking of packet based on source or the destination MAC address.

-Forwarding to specific ports based on source MAC address.

-Forcing traffic to specific ports based on the destination MAC address.

•Token-Ring Features:

−Supports 8 shielded TRN UTP/STP RJ45 lobe ports using either UTP category 3,4, or 5 cabling, or STP cabling.

Note

These ports do not support RI or RO connections. Use the 2-Port Fiber RI/RO UFC to handle RI or RO connections.

−Have either two UFC slots (2-slot modules) or four UFC slots (3-slot modules), which can contain any combination of the following UFCs:

-4-Port UTP/STP

This UFC adds an additional four switched TRN ports to the module.

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Interface: RJ45

Cabling: STP; UTP categories 3, 4, and 5

72ATM Workgroup Solutions: Implementing the 8285 ATM Switch