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NexLog Recorder User Manual v2.2.0
Network Requirements
The following requirements apply to recording VoIP calls:
Unlike a PBX phone system, which has a centralized switch from which to
tap the telephone calls, a VoIP system transmits the calls over a distributed
intranet, which also carries other data traffic. To capture and record VoIP
calls from the intranet, you must configure your intranet topology to mirror
or send a copy of the VoIP packets to a single Ethernet port, which is
connected either to the Eventide NexLog Recorder (for Local VoIP) or to the
Eventide VoIP Gateway. For example, this can be accomplished using a
Cisco Systems Ethernet switch that supports Switched Port Analyzer (SPAN)
technology or Remote Switched Port Analyzer (RSPAN) technology. These
components create copies of the audio packets being sent across the
network and send them to another designated port for network analysis. In
the case of RSPAN, it places audio traffic on a SPAN port from different
network switches.
For detailed information on SPAN and RSPAN, go to the following page on
the Cisco Systems web site:
www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12113ea1/3550scg/s
wspan.htm
In addition to SPAN or RSPAN, some systems use direct unicast or multicast
connections to the recorder.
When using the
Local VoIP
feature on an Eventide NexLog Recorder, the
recorder must be equipped with two network interface cards (NICs) if you are
using SPAN/RSPAN. (One port is used for the unidirectional VoIP traffic sent
to the recorder, and one port for bidirectional traffic with clients.)
The
Eventide VoIP Gateway
is equipped with two NICs standard from the
factory, and can be used with SPAN/RSPAN.
Eventide suggests implementing VoIP on a virtual local area network (VLAN).
A VLAN is a logical group on the network that effectively prioritizes network
traffic to ensure enough bandwidth. VLANs also greatly ease the
configuration issues surrounding SPAN and RSPAN ports.
The MAC or IP addresses of all active phone sets must be designated.
This
information is entered in Configuration Files area of the NexLog Recorder
Configuration program. (For more information, see
.) Additionally,
port ranges
for both the signaling ports (the
call’s attributes) and audio ports (the actual audio data packets) must be
designated. Only calls that occur on ports in these designated ranges are
recorded; all others are ignored.