Installation manual

Fast SwitcHub-2se User’s Guide
Introduction 1-3
speed 100BASE-TX or conventional 10BASE-T networks to the newer
generation of 100BASE-FX devices; or can be used to significantly extend a
100BASE-TX or 10BASE-T network with an intermediate fiber optic link (i.e.,
by chaining two or more switches). Moreover, by breaking your network into
smaller and more manageable segments, each linked to the larger network with
a switch, the maximum distance for communications between end-nodes is
unlimited.
Switching Methods
Traditional bridges and routers use a switching method called store-and-
forward in which the entire frame must be received before the bridge can
perform a table look-up for the destination node and forward the packet to the
corresponding port. As a result, each packet experiences a hefty delay. It may
be necessary to use store-and-forward when a lot of data errors are occurring
over the network, or when connecting to very slow devices. Compared to this
“safe” mode of operation, cut-through switching significantly reduces packet
transmission delay by picking the destination address out of the header as soon
as its received, and directing the frame to the appropriate port long before the
full packet has been received.
Another technique, employed to improve data reliability, is called fragment-
free cut-through. It uses a more conservative approach to cut-through that
waits until the collision window has elapsed (i.e., the first full 64 bytes has
been received) before processing the packet. This prevents runts from being
passed along, effectively cleaning up the data stream.
Although cut-though switching is recommended as the fastest method for most
applications, the other methods mentioned above are also supported by the Fast
SwitcHub-2se to guarantee flawless performance. To ensure that you can
manage any kind of network load, the Smart Extender uses adaptive cut-
through switching based on Accton’s smart algorithm. This method