Users Guide

78 Switch Feature Overview
Switching Features
Flow Control Support (IEEE 802.3x)
Flow control enables lower speed switches to communicate with higher speed
switches by requesting that the higher speed switch refrain from sending
packets for a limited period of time. Transmissions are temporarily halted to
prevent buffer overflows.
For information about configuring flow control, see "Port-Based Traffic
Control" on page 899.
Head of Line Blocking Prevention
Head of Line (HOL) blocking prevention prevents traffic delays and frame
loss caused by traffic competing for the same egress port resources. HOL
blocking queues packets, and the packets at the head of the queue are
forwarded before packets at the end of the queue.
Jumbo Frames Support
Jumbo frames enable transporting data in fewer frames to ensure less
overhead, lower processing time, and fewer interrupts.
For information about configuring the switch MTU, see "Port Characteristics"
on page 623.
Auto-MDI/MDIX Support
The switch supports auto-detection between crossed and straight-through
cables. Media-Dependent Interface (MDI) is the standard wiring for end
stations, and the standard wiring for hubs and switches is known as Media-
Dependent Interface with Crossover (MDIX). Auto-negotiation must be
enabled for the switch to detect the wiring configuration. NBASE-T ports
(2.5G and 5G) do not support auto-detection. Use the correct crossover or
straight-through cable on 2.5/5G NBASE-T interfaces.
VLAN-Aware MAC-based Switching
Packets arriving from an unknown source address are sent to the CPU and
added to the Hardware Table. Future packets addressed to or from this
address are more efficiently forwarded.