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 Ethernet Routing Switch 3500 Series 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 Ethernet Routing Switch 3500
Series, 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 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
ACLI
March 2013 67