Chapter 9: Managing Ethernet Ports Using Acli; Autosensing And Autonegotiation; Custom Autonegotiation Advertisements - Avaya 3500 Series Getting Started

Chapter 9: Managing Ethernet ports using

Autosensing and autonegotiation

The switch is an autosensing and autonegotiating device.
• The term autosense refers to the ability of a port to sense the speed of an attached device.
• The term autonegotiation refers to a standardized protocol (IEEE 802.3u) that exists between
two IEEE 802.3u-capable devices. Autonegotiation lets the switch select the best of speed and
duplex modes.
Autosensing is used when the attached device is not capable of autonegotiation or is using a form of
autonegotiation that is not compatible with the IEEE 802.3u standard. In this case, because it is not
possible to sense the duplex mode of the attached device, the Ethernet Routing Switch 3500 Series
reverts to half-duplex mode.
When autonegotiation-capable devices are attached to the switch, the ports negotiate down from
1000 Mb/s speed and full-duplex mode (ERS 3510GT and ERS 3524GT) and from 100 Mb/s speed
and full-duplex mode (ERS 3526T) until the attached device acknowledges a supported speed and
duplex mode.

Custom Autonegotiation Advertisements

Custom Autonegotiation Advertisements (CANA) lets you customize the capabilities that you
advertise. For example, if a port is not capable of 10/100/1000 full duplex operation, the port can be
configured to only advertise 10 half-duplex capabilities.
CANA lets you control the capabilities that are advertised by the Ethernet switches as part of the
autonegotiation process. In the current software releases, autonegotiation can either be enabled or
disabled.
When autonegotiation is disabled, the hardware is configured for a single (fixed) speed and duplex
value. When autonegotiation is enabled, the advertisement made by the product is a constant value
based upon all speed and duplex modes supported by the hardware.
When autonegotiating, the switch selects the highest common operating mode supported between
the switch and its link partner.
Getting Started with Avaya ERS 3500 Series
94
ACLI
Comments on this document? infodev@avaya.com
July 2015