P-660R-Tx v2 Series Support Notes
13. What is Traffic Shaping?
Traffic Shaping is a feature in the P-660R-Tx v2. It allocates the bandwidth to
WAN dynamically and aims at boosting the efficiency of the bandwidth. If there
are serveral VCs in the P-660R-Tx v2 but only one VC activated at one time,
the P-660R-Tx v2 allocates all the Bandwidth to the VC and the VC gets full
bandwidth. If another VCs are avtivated later, the bandwidth is yield to other
VCs after ward.
14. What do the parameters (PCR, SCR, MBS) mean?
Traffic shaping parameters (PCR, SCR, MBS) can be set in Menu 4 and Menu
11.6 and is valid for both incoming and outgoing direction since G.shdsl is
symmetric.
Peak Cell Rate(PCR):
The maximum bandwidth allocated to this connection.
The VC connection throughput is limited by PCR.
Sustainable Cell Rate(SCR):
The least guaranteed bandwidth of a VC.
When there are multi-VCs on the same line, the VC throughput is guaranteed
by SCR.
Maximum Burst Size(MBS):
The amount of cells transmitted through this
VC at the Peak Cell Rate before yielding to other VCs. Total bandwidth of the
line is dedicated to single VC if there is only one VC on the line. However, as
the other VC asking the bandwidth, the MBS defines the maximum number of
cells transmitted via this VC with Peak Cell rate before yielding to other VCs.
The P-660R-Tx v2 holds the parameters for shaping the traffic among its
virtual channels. If you do not need traffic shaping, please set SCR = 0, MBS =
0 and PCR as the maximum value according to the line rate (for example, 2.3
Mbps line rate will result PCR as 5424 cell/sec.)
15.Why do we perform traffic shaping in the P-660R-Tx v2 ?
The P-660R-Tx v2 must manage traffic fairly and provide bandwidth allocation
for different sorts of applications, such as voice, video, and data. All
applications have their own natural bit rate. Large data transactions have a
fluctuating natural bit rate. The P-660R-Tx v2 is able to support variable traffic
among different virtual connections. Certain traffic may be discarded if the
virtual connection experiences congestion. Traffic shaping defines a set of
actions taken by the P-660R-Tx v2 to avoid congestion; traffic shaping takes
measures to adapt to unpredictable fluctuations in traffic flows and other
problems among virtual connections.
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