Nortel Networks 2500 Series Ethernet port management features, Configuring Lldp using the CLI

Ethernet port management features 77

LLDPDU and TLV error handling LLDPDUs and TLVs that contain detectable errors are discarded. TLVs that are not recognized, but that also contain no basic format errors, are assumed to be validated and are stored for possible later retrieval by network management.

Configuring LLDP using the CLI

For information about configuring LLDP using the CLI, see "Configuring LLDP using the CLI" (page 77).

Ethernet port management features

Autosensing and autonegotiation

The Ethernet Routing Switch 2500 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 2500 Series reverts to half-duplex mode.

When autonegotiation-capable devices are attached to the Ethernet Routing Switch 2500 Series, the ports negotiate down from 100 Mb/s speed and full-duplex mode 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.

Nortel Ethernet Routing Switch 2500 Series

Overview — System Configuration

NN47215-500 (323162-B) 02.02 Standard

4.1 19 November 2007

Copyright © 2007, Nortel Networks