Mdi/Mdi-X Detection; Flow Control; Priority - Avaya c360 Installation And Configuration Manual

Avaya C360 Layer 2 Features

MDI/MDI-X Detection

Auto MDI/MDI-X (cross-over cable) detection allows use of both straight and crossover cables
without the need to configure ports individually.

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 C360 supports four internal priority queues and the classification of packets within the
queues is as follows:
This classification is based either on the packet's original priority tag, or, if the packet arrives at
the port untagged, based on the priority configured for the ingress port (using the set port
level CLI command).
In cases where the packet was received tagged, this priority tag is retained when the packet is
transmitted through a tagging port.
116 Installation and Configuration Guide Avaya C360 Multilayer Stackable Switches, version 4.5
Table 29: Packet Tagging to C360 Queue Mapping
Tagging
0, 1
2, 3
4, 5
6, 7
C360 Queue
Low
Normal
High
Highest