DATA LINK LAYER WIRED NETWORKS
WIRED LANS ETHERNET PROTOCOL
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
has a positive impact on bandwidth by dropping most of the invalid frames
|
|
|
makes a fast forwarding decision based on the source MAC address of the frame
|
|
|
has a lower latency appropriate for high-performance computing applications​
|
|
|
provides the flexibility to support any mix of Ethernet speeds
|
Detailed explanation-1: -The primary advantage of cut-through Ethernet switches, compared to store-and-forward Ethernet switches, is lower latency. Cut-through Ethernet switches can support an end-to-end network delay latency of about 10 microseconds.
Detailed explanation-2: -A cut-through device begins forwarding a frame after examining only the first part of its header. In contrast, a store-and-forward switch buffers the entire frame before making a forwarding decision. In general, this buffering before transmission can cause long delays.
Detailed explanation-3: -There are two primary characteristics of cut-through switching: rapid frame forwarding and fragment free. As indicated in the figure, a switch using the cut-through method can make a forwarding decision as soon as it has looked up the destination MAC address of the frame in its MAC address table.
Detailed explanation-4: -In cut-through switching mode, switches receive only a fraction of the frame and immediately start making a forwarding decision. In this approach, switches do not drop invalid frames but forward them to the next node. However, the network latency is lower than with the store-and-forward approach.