Avaya P3343T-ML 사용자 설명서

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Chapter 11        Avaya P330 Layer 2 Features
Avaya P334T-ML User’s Guide
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Speed
The IEEE defines three standard speeds for Ethernet: 10, 100 and 1000 Mbps (also 
known as Ethernet, Fast Ethernet and Gigabit Ethernet respectively).
Flow Control
The process of adjusting the flow of data from one device to another to ensure that 
the receiving device can handle all of the incoming data. This is particularly 
important where the sending device is capable of sending data much faster than the 
receiving device can receive it. 
There are many flow control mechanisms. One of the most common flow control 
protocols, used in Ethernet full-duplex, is called xon-xoff. In this case, the receiving 
device sends a an xoff message to the sending device when its buffer is full. The 
sending device then stops sending data. When the receiving device is ready to 
receive more data, it sends an xon signal. 
Priority
By its nature, network traffic varies greatly over time, so short-term peak loads may 
exceed the switch capacity. When this occurs, the switch must buffer frames until 
there is enough capacity to forward them to the appropriate ports. 
This, however, can interrupt time-sensitive traffic streams, such as Voice and other 
converged applications. These packets need to be forwarded with the minimum of 
delay or buffering. In other words, they need to be given high priority over other 
types of network traffic.
Priority determines in which order packets are sent on the network and is a key part 
of QoS (Quality of Service). The IEEE standard for priority on Ethernet networks is 
802.1p. 
The Avaya P334T-ML supports two internal priority queues – the High Priority 
queue and the Normal Priority queue – on its Gigabit Ethernet ports (51,52) and 
four internal priority queues on its 10/100Mbps ports. The classification of packets 
within the queues is as follows:
Gigabit  Ethernet  ports:
— packets tagged with priorities 4-7 are assigned to the High Priority queue
— packets tagged with priorities 0-3 are assigned to the Normal Priority 
queue.
10/100Mbps ports:
— packets tagged with priorities 0-1 are assigned to the Low Priority queue
— packets tagged with priorities 2-3 are assigned to the Normal Priority 
queue;
— packets tagged with priorities 4-5 are assigned to the High Priority queue
— packets tagged with priorities 6-7 are assigned to the Highest Priority 
queue.