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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
.