Interface and Hardware Component Command Reference, Cisco IOS XE Release 3SE (Catalyst 3850 Switches)
clock rate through cut-through
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clock rate through cut-through

clock rate through cut-through

cut-through

To configure the interfaces on the PA-12E/2FE port adapter to use cut-through switching technology between interfaces within the same bridge group, use the cut-throughcommand in interface configuration mode. To return each interface to store-and-forward switching, use the noform of this command.

cut-through [ receive | transmit ]

no cut-through

Syntax Description

receive

(Optional) Selects cut-through switching technology on received data.

transmit

(Optional) Selects cut-through switching technology on transmitted data.

Command Default

Store-and-forward switching technology (that is, no cut-through)

Command Modes

Interface configuration

Command History

Release

Modification

11.2P

This command was introduced.’

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

Usage Guidelines

Cut-through mode allows switched packets to be transmitted after 64 bytes are received. The transmission of the packets can start before the end of the packet arrives. This reduces the time spent in the switch, but allows packets to be transmitted with bad cyclical redundancy checks (CRCs), because the transmission is initiated before the CRC is received or checked. Store-and-forward mode waits for the entire packet to be received before that packet is forwarded, but will check the CRC before starting transmission.

The PA-12E/2FE port adapter offloads Layer 2 switching from the host CPU by using store-and-forward or cut-through switching technology between interfaces within the same VLAN on the PA-12E/2FE port adapter. The PA-12E/2FE port adapter supports up to four VLANs (bridge groups).

Examples

The following example configures interface 3/0 for cut-through switching:

Router(config)#
 interface fastethernet 3/0
Router(config-if)#
 bridge-group 10
Router(config-if)#
 cut-through
Router(config-if)#
 no shutdown
Router(config-if)# exit