User manual

4200 User Manual Edgewater Networks, Inc.

Version 2.2 34

if necessary) when sent to the LAN interface by the 4200 appliance. Similarly data

traffic sent back to the 4200 for transmission to the WAN are also delayed. This

results in the end stations slowing down their transmit rate. This technique is quite

effective in practice as end stations usually reduce their transmit rate before VoIP

signaling has completed for new call setup.

For example consider the scenario where there are no voice calls over a SDSL WAN

link and multiple FTP sessions are consuming all available bandwidth:

1) A new call request is received by the 4200 from the WAN.

2) All signaling messages for the call are classified as voice traffic and

prioritized for transmission over the LAN before servicing FTP data.

3) RTP traffic is similarly classified as voice traffic and treated with priority.

4) FTP data is buffered (or dropped) on the egress LAN port and ACKs are also

delayed on the egress WAN port. This throttles the transmit rate of the FTP

hosts to reduce overall WAN bandwidth consumption.

Excessive UDP traffic must be shaped in the service provider network, as UDP does

not provide congestion avoidance mechanisms. The exception to this is in the case

of RTP messages for voice traffic. Although RTP is based on UDP, the 4200 appliance

provides its own congestion avoidance mechanism for voice traffic using Call

Admission Control (CAC).

Chapter 4: System Diagnostics

The 4200 provides a powerful set of diagnostic information, troubleshooting tools

and utilities for system maintenance to network operators.

Viewing Software Version, Hardware Platform and the LAN MAC

Address

The software version, hardware platform, and

LAN MAC address are common pieces of

information requested by technical support and

are accessed directly through the System page

of the 4200 web GUI.

To ensure that you are running the latest

software version please visit our website for a

complete listing of software releases at:

http://www.edgewaternetworks.com/Support/SupportDocLanding.html#ReleaseNote

Viewing the ALG registration code

You will also find a link to the ALG registration code on the System page. The