42 Chapter 1 BayStack 380 Switch212859-APort mirroring (conversation steering)The port mirroring feature (sometimes referred to as conversation steering) allowsyou to designate a single switch port as a traffic monitor for a specified port. Youcan specify port-based monitoring for ingress and egress at a specific port. Youcan also attach a probe device (such as a Nortel Networks StackProbe, orequivalent) to the designated monitor port.For more information about the port mirroring feature, see “Port MirroringConfiguration screen” on page 142.Autosensing, autonegotiation, auto-MDI/X, and autopolarityThe BayStack 380 switches are autosensing and autonegotiating devices:• The term autosense refers to a port’s ability to sense the speed of an attacheddevice.• The term autonegotiation refers to a standardized protocol (IEEE 802.3u or802.3z or 802.3ab) that exists between two IEEE -capable devices.Autonegotiation allows the switch to select the best of both speed and duplexmodes.• The term autopolarity refers to automatic detection of transmit and receivetwisted pairs.Autosensing is used when the attached device is not capable of autonegotiation oris using a form of autonegotiation that is not compatible with the IEEE 802.3zautonegotiation standard. In this case, because it is not possible to sense theduplex mode of the attached device, the BayStack 380 Switch reverts tohalf-duplex mode.When autonegotiation-capable devices are attached to the BayStack 380 Switch,the ports negotiate down from 1000 Mb/s speed and full-duplex mode until theattached device acknowledges a supported speed and duplex mode.Auto-MDI-X detects receive and transmit twisted pairs automatically. Whenauto-MDI-X is active, any straight or crossover category 5 cable can be used toprovide connection to a port. If autonegotiation is disabled, then auto-polarity isnot active.
