Cisco試題:交換機考題分析

原題:

what is the basic characteristic of switches and hubs?

a. hubs cannot filter frames.
b. using hubs is costly with regard to bandwidth availability.
c. switches do and can not forward broadcasts.
d. switches are more efficient than hubs in processing frames.
e. switches increase the number of collision domains in the network.

漢意:

交換機與集線器的基本特徵是什麼?

正確答案:e

解釋:

交換機增加網路中衝突域的數量。

注意:

交換機在內部處理中有一些不同類型的變數,儘管現在的交換機基本上都使用store-and-forward,但是大部分思科交換機,至少支持以下三種不同類型中的一種。

• store-and-forward -the switch fully receives all bits in the frame (store) before forwarding the frame (forward).

• cut-through - the switch performs the address table lookup as soon as the destination address field in the header is received.

• fragment-free - this performs like cut-through switching, but the switch waits for 64 bytes to be received before forwarding the first bytes of the outgoing frame.

參考資料:

sybex ccna 4.0 640-801

ccna self-study ccna icnd exam certification guide(ciscopress,isbn 1-58720-083-x)