Nortel Networks 1000ASE-XD - Manual (Page 40)

40 Chapter 1 BayStack 420 Switch
209418-A
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
autonegotiation standard. In this case, because it is not possible to sense the
duplex mode of the attached device, the BayStack 420 Switch reverts to
half-duplex mode.
When autonegotiation-capable devices are attached to the BayStack 420 Switch,
the ports negotiate down from 100 Mb/s speed and full-duplex mode until the
attached device acknowledges a supported speed and duplex mode.
Autpolarity detects receive and transmit twisted pairs automatically. When
autopolarity is active, any straight or crossover category 5 cable can be used to
provide connection to a port. If the port is set to a fixed configuration, then
autopolarity is not active.
For more information about autosensing and autonegotiation modes, see
Chapter 4, “Troubleshooting,” on page 173 .
RFCs
For more information about networking concepts, protocols, and topologies,
consult the following RFCs:
• RFC 1213 (MIB-II)
• RFC 1493 (Bridge MIB)
• RFC 1573 (Interface MIB)
• RFC 1643 (Ethernet MIB)
• RFC 1757 (RMON)
• RFC 1271 (RMON)
• RFC 1157 (SNMP)
Standards
The following IEEE Standards also contain information germane to the BayStack
420 Switch:
• IEEE 802.1D (Standard for Spanning Tree Protocol)
• IEEE 802.3 (Ethernet)
• IEEE 802.1Q (VLAN Tagging)