Allied Telesis AT-S20 - Manual (Page 46)

Enabling Store-and-forward or Cut-through (Fragment-Free)
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Cut-through (fragment-free). This option is available for non-XL
versions only. In this method, the switch starts to forward the
incoming packet to its destination while the packet is still being
received.
Cut-through (fragment-free) provides low latency for forwarding
frames and also filtering fragment frames by not transmitting a
frame until 64 bytes have been received by the switch. In cut-
through (fragment-free) mode, fragment frames or runts (frames
less than 64 bytes) are filtered, thus providing some network error
protection.
Select the cut-through (fragment-free) method if you are running
time-sensitive applications.