Avaya 4524GT, Руководство по настройке

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When you use the TDR to test a cable with a 10/100 MB/s link, the link is interrupted for the
duration of the test and restored when the test is complete. Because ports that operate at
slower speeds do not use all of the connected pins, test results for a port with a 10/100 MB/s
link can be less detailed than test results for a port with a 1Gb/s link.
You can use the TDR to test cables from 5 to 120 meters in length with a margin of accuracy
between 3 and 5 meters.
The TDR cannot test fibre optic cables.
Autosensing and autonegotiation
The Avaya Ethernet Routing Switch 4500 Series are autosensing and autonegotiating devices:
• The term autosense refers to the ability of a port to sense the speed of an attached
device.
• The term autonegotiation refers to a standard protocol (IEEE 802.3u or 802.3z or 802.3ab)
that exists between two IEEE-capable devices. Autonegotiation enables the switch to
select the best speed and duplex modes.
Autosensing occurs when the attached device cannot autonegotiate or uses a form of
autonegotiation that is not compatible with the IEEE 802.3z autonegotiation standard. If it is
not possible to sense the duplex mode of the attached device, the Avaya Ethernet Routing
Switch 4500 Series reverts to half-duplex mode.
When autonegotiation-capable devices are attached to the Avaya Ethernet Routing Switch
4500 Series, the ports negotiate down from 1000 Mb/s and full-duplex mode until the attached
device acknowledges a supported speed and duplex mode.
Custom Autonegotiation Advertisements
In the Avaya Ethernet Routing Switch 4500 Series, you can use the Custom Autonegotiation
Advertisements (CANA) feature to control the speed and duplex settings that each Ethernet
port of the device advertises as part of the autonegotiation process.
Without CANA, a port with autonegotiation enabled advertises all speed and duplex modes
supported by the switch and attempts to establish a link at the highest common speed and
duplex setting. By using CANA, you can configure the port to advertise only certain speed and
duplex settings, thereby establishing links only at these settings, regardless of the highest
commonly supported operating mode.
CANA provides control over the IEEE802.3x flow control settings advertised by the port, as
part of the autonegotiation process. You can set flow control advertisements to Symmetric,
Asymmetric, or Disabled.
System configuration fundamentals
42 Configuration — System April 2011