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Download ECS5510-48S Management Guide - Edge-Core
Transcript
CHAPTER 14 | Configuring DCE Cut-Through CUT-THROUGH In cut-through switching the switch starts forwarding a frame before the whole frame has been received, normally as soon as the destination address is processed. Cut-through reduces latency through the switch. LIMITATIONS AND The disadvantage of Cut-through are: INTERACTIONS WITH OTHER FEATURES ◆ The FCS of the frame is not checked prior to transmitting the packet. ◆ Cut-through switching can only be used where the speed of the outgoing interface is less than or equal to the incoming interface speed. ◆ The packet size is unknown at the time of deciding whether to transmit the packet The following limitations should be considered: ◆ PFC, QCN and Shaping cannot be enabled if there is at least one port that is configured for Cut-through. ◆ Cut-through cannot be enabled for a port if PFC or QCN or Shaping is enabled. ◆ Policing and Rate-Limiting for a port cannot be enabled if the port is configured for Cut-through. ◆ Cut-through for a port cannot be enabled if a policer or rate-limiter is enabled for that port. ◆ In case jumbo frame forwarding is disabled and Cut Through is enabled, Jumbo frames are forwarded, but the device marks the CRC as bad. CONFIGURING CUT- To configure cut-through: THROUGH 1. Click DCE > Cut-through in the tree view to display the Cut-through Page. – 330 –
