Dell PowerConnect 6248 User's Guide - Page 25

Port-Based Features Jumbo Frames Support Jumbo frames enable transporting data in fewer frames to ensure less overhead, lower processing time, and fewer interrupts. 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 Auto negotiation allows the switch to advertise modes of operation. The auto negotiation function provides the means to exchange information between two switches that share a point-to-point link segment, and to automatically configure both switches to take maximum advantage of their transmission capabilities. The PowerConnect 6200 Series enhances auto negotiation by providing port advertisement. Port advertisement allows the system administrator to configure the port speeds advertised. For information about auto negotiation, see "Port Configuration" or "LAG Configuration." 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 refrains from sending packets. Transmissions are temporarily halted to prevent buffer overflows. For information about configuring flow control for ports or LAGs, see "Port Configuration" or "LAG Configuration." 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. Back Pressure Support On half-duplex links, a receiver may prevent buffer overflows by occupying the link so that it is unavailable for additional traffic. Introduction 25