10/100/1000 Crossover Supported; Autonegotiation Guidelines - Alcatel-Lucent OmniSwitch 6850-48 Network Configuration Manual

Ethernet Ports Overview
NI Module
OS9-GNI-C20L
(ports 21–22)
OS9-GNI-C48T
OS9-XNI-U2 / U2E 2 fiber XFP
OS9-XNI-U6
Fast Ethernet, Gigabit Ethernet, and 10 Gigabit Ethernet switching modules can be used as backbone links,
with Gigabit Ethernet and 10 Gigabit Ethernet modules offering additional support for high-speed servers.
All modules support 802.1Q hardware tagging for enhanced compatibility. And all Gigabit and 10 Gigabit
modules support jumbo frame configuration.
See the OmniSwitch 9000 Hardware Users Guide for more information about the OmniSwitch 9000 hard-
ware that is available in the current release.

10/100/1000 Crossover Supported

By default, automatic crossover between MDI/MDIX (Media Dependent Interface/Media Dependent Inter-
face with Crossover) media is supported on all the OmniSwitch ports. Therefore, either straight-through or
crossover cable can be used between two ports as long as autonegotiation is configured on both sides of
the link. See "Configuring Autonegotiation and Crossover Settings" on page 1-18

Autonegotiation Guidelines

Please note a link will not be established on any copper Ethernet port if any one of the following is true:
•
The local port advertises 100 Mbps full duplex and the remote link partner is forced to 100 Mbps full
duplex.
•
The local port advertises 100 Mbps full duplex and the remote link partner is forced to 100 Mbps half
duplex.
•
The local port advertises 10 Mbps full duplex and the remote link partner is forced to 10 Mbps full
duplex.
•
The local port advertises 10 Mbps full duplex and the remote link partner is forced to 10 half duplex.
This is due to the fact that when the local device is set to auto negotiating 10/100 full duplex it senses the
remote device is not auto negotiating. Therefore it resolves to Parallel Detect with Highest Common
Denominator (HCD), which is "10/100 Half" according to IEEE 802.3 Clause 28.2.3.1.
However, since the local device is set to auto negotiating at 10/100 full duplex it cannot form a 10/100
Mbps half duplex link in any of the above mentioned cases. One solution is to configure the local device to
autonegotiation, 10/100 Mbps, with auto or half duplex.
page 1-8
Port Number/Type
Non-combo SFP connectors
48 Mini RJ-21 ports
6 fiber XFP
OmniSwitch AOS Release 6 Network Configuration Guide
User-Specified User-Specified
Port Speed Duplex
(Mbps) Supported
Supported
Dependent Dependent
auto/10/100/ auto/full/half
1000
10000 full
10000 full
Configuring Ethernet Ports
Auto
Negotiation
Supported?
Dependent
Yes
No
No
for more information.
September 2009