Lucent Technologies CAJUN P120, User Manual

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Chapter 1 Overview
Cajun P120 User’s Guide 5
Auto-negotiation
Auto-negotiation is a protocol between two link partners that enables a port to
advertise its transmission rate and duplex mode to its partner. Both ports then
operate at the highest common denominator between them. This saves you from
having to configure the Cajun P120 10/100BASE-TX ports’ speed and duplex mode
to match that of the connected device.
On 1000Base Expansion Sub-module ports, Auto-negotiation controls the Flow
Control Mode (Symmetric/Disabled).
Note: Auto-negotiation works only when both link partners are set to auto-
negotiation mode. If you connect a NIC (or a Cajun P120 Uplink-100 port) that
does not support autoneg (or autoneg disabled) to a Cajun P120 port, then we
recommend that you manually set both the P120 port and the NIC to the same
speed and duplex mode.
Port Mirroring
The Cajun P120 has a built-in ”mirroring” capability, that allows forwarding of all
the traffic to/from specific ”copy source” to a ”copy destination” (also called a
probe-port or sniffer-port), excluding errors and frames with errors.
When you require detailed information about the traffic at a particular port, rather
than attaching an expensive analyzer to each port (or moving such a probe from
port to port), the network administrator may attach an external probe to any
Cajun P120 port defined as a destination port and analyze any switched port by
mirroring its Rx/Tx traffic to that destination port.
Port mirroring should be activated on ports that belong to the same VLAN.
FEFI
The Cajun P120 supports FEFI (Far End Fault Indication) on the 100Base-FX ports.
This enables the Cajun P120 to detect and report a link failure even if it is only a Tx
line failure (while the Rx line is still OK).
When a 100Base-FX port receives a FEFI indication, a switchover to a redundant
link occurs, if there is one assigned to this port. If the port is part of a LAG, then the
traffic from this link will be moved to the other links of the LAG, until the link's
fault status is corrected.
Address Aging
The Cajun P120 supports the aging of addresses in the CAM table.