Juniper Networks IDP 800 NIC Bypass and Cable Choices, External Bypass Unit State, NICs Off State

IDP 75, 250, 800, and 8200 Installation Guide

The fiber Ethernet ports are standard interfaces and do not incorporate the integrated bypass feature. Automatic bypass is available for fiber ports through third-party devices.

NIC Bypass and Cable Choices

When NIC bypass becomes active, it physically connects the pair of forwarding interfaces to each other with a crossover cable.

If you are connecting devices that support auto-MDIX (medium dependent interface crossover) to automatically switch to the proper configuration after a cable is connected, and then you can use whatever cables you want, because auto-MDIX negotiates the correct connection. However, if neither of the devices supports auto-MDIX, and then you need to take special care to choose the right cables.

Suppose two devices, one connected to one sensor port and the other connected to the other sensor port, are instead connected directly together.

„If the two devices are connected with a straight-through cable, use one straight-through cable and one crossover cable to connect the sensor to these devices. When NIC bypass starts, the resulting effect is to create one, long straight-through cable connecting the devices.

„If the two devices are connected with a cross-over cable, use two straight-through cables to connect the sensor to these two devices. When NIC bypass starts, the resulting effect is to create one, long straight-through cable connecting the devices.

External Bypass Unit State

This state is only available when the sensor is in transparent mode. It behaves the same as normal state, except that NSRP packets are passed even if Layer 2 bypass is not enabled.

NOTE: The External Bypass Unit setting is global. Selecting it for any interface pair enables it for all interface pairs on the sensor. If enabled for one interface pair, all interface pairs pass NSRP packets regardless of their individual settings.

The external bypass unit state appears only in the after system unavailability list of the ACM. However, selecting it there enables it globally for all states.

NICs Off State

During sensor operation, this state behaves the same as normal state. NSRP heartbeats are not passed unless the sensor is in transparent mode and Layer 2 bypass is enabled. The difference is this: when the sensor software becomes unavailable because of graceful shutdown or unexpected failure, the NICs turn off and no longer appear live to other devices on the network.

This setting is not global. It must be selected for each interface pair and in each mode (after system unavailability and after graceful shutdown).

12„ Traffic Ports (Forwarding Interfaces)