Viavi 10/100 Copper nTAP, Руководство пользователя

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Choosing between a SPAN, Aggregator, or full-duplex TAP
Chapter 2: Why choose a TAP or SPAN port 13
protection against packet loss, but if usage spikes exceed its buffer capacity
before the link to the analyzer can catch up, the Aggregator TAP drops packets.
To monitor a critical, heavily utilized full-duplex link, a full-duplex TAP is the only
alternative. Monitoring a full-duplex connection using a full-duplex TAP and an
analyzer with a dual-receive capture interface guarantees complete, full-duplex
capture for monitoring, analysis, and intrusion detection regardless of bandwidth
saturation.
When to use a full-duplex TAP
A full-duplex TAP is the only option guaranteeing all of the network traffic makes
it to the analysis device (including Layer 1 and 2 error information). Although
this can be the most expensive option, it is also the only option that guarantees
complete accuracy when the network is highly saturated.
A full-duplex TAP is more complex and potentially expensive to implement, but
where there is high network utilization and an importance to guarantee the
capture of “everything on the wire” along with errors from all network layers,
a full-duplex TAP is the only choice. If the analysis requires a high level of data
stream fidelity (for instance, looking for jitter in video or VoIP), only a full duplex
TAP forwards the original data timing to the analyzer.
Note: A full-duplex TAP must be coupled with a probe or monitoring device
capable of receiving both channels of a full-duplex signal and recombining
the two channels into a single data stream for analysis.
A full-duplex TAP is a passive mechanism that is installed between two network
devices. An Optical TAP is non-electronic (no power) and optically splits the
signal into two full-duplex signals. One signal maintains the network link, while
the other is passed to an analyzer equipped with a dual-receive capture card. A
Copper TAP performs the same function, but uses electronic circuitry to duplicate
the signals.
Because a full-duplex TAP copies both the send and receive channels from a
full-duplex link to the analyzer (where the data is integrated), the analyzer can
monitor a full-duplex network at line rate—assuming the capture card in the
analyzer is capable.
All TAPs from VIAVI, except the Aggregator TAP family, are full-duplex TAPs.