Network Tap - ProfiTap PROFISHARK 1G User Manual

Network TAP

The ProfiShark 1G integrated network TAP provides safe
access to the network for monitoring purposes. It is a passive
monitoring device, in the sense that it is undetectable, the
original traffic staying unaltered and no extra packets being
inserted. As most of the TAP's functions are performed by
dedicated hardware circuits, it is much more reliable and error
proof than SPAN ports.
In a gigabit network, the TAP has to negotiate with both
attached devices for the highest common speed. If no common
speed can be found, or if one of the devices is disconnected,
the TAP propagates the error to the other attached device,
allowing a redundant path to be activated.
In case of power failure, it activates its bypass circuits,
connecting the two attached devices directly. The ProfiShark
1G integrates a high performance fast failover circuit and
a proprietary algorithm, reducing the unavailability of the
network path down to 30ms.
NOTE The fast failover relies on the network setup. In case
the fast failover cannot perform, the two end devices have to
renegotiate the link. This operation takes about 2 seconds.
NOTE The user should verify that the two end devices connect
together with either a single cable, an RJ45 coupler, or the
unpowered TAP. The straight or crossover cables must be
employed in case of end devices that do not support Auto MDI/
MDIX operation (i.e. Auto Crossover). Experienced users can
bypass this procedure.
NOTE Although some vendors recommend the use of the
non-IEEE compliant "Forced Gigabit" mode, we strongly
recommend activating auto-negotiation when Gigabit speed is
required. More generally, auto-negotiation should always be
enabled on both end devices in order to avoid duplex mismatch
issues.
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