Traffic Parameters; Peak Cell Rate (Pcr); Sustained Cell Rate (Scr); Maximum Burst Size (Mbs) - ZyXEL Communications P-861H-G2 User Manual

5.3.2 Traffic Parameters

These are the parameters that control the flow of ATM traffic.

5.3.2.1 Peak Cell Rate (PCR)

Peak Cell Rate (PCR) is the maximum rate at which the sender can send cells. This parameter
may be lower (but not higher) than the maximum line speed. 1 ATM cell is 53 bytes (424 bits),
so a maximum speed of 832Kbps gives a maximum PCR of 1962 cells/sec. This rate is not
guaranteed because it is dependent on the line speed.

5.3.2.2 Sustained Cell Rate (SCR)

Sustained Cell Rate (SCR) is the mean cell rate of each bursty traffic source. It specifies the
maximum average rate at which cells can be sent over the virtual connection. SCR may not be
greater than the PCR.

5.3.2.3 Maximum Burst Size (MBS)

Maximum Burst Size (MBS) is the maximum number of cells that can be sent at the PCR.
After MBS is reached, cell rates fall below SCR until cell rate averages to the SCR again. At
this time, more cells (up to the MBS) can be sent at the PCR again.

5.3.2.4 Minimum Cell Rate (MCR)

Minimum Cell Rate (MCR) is the minimum rate at which the sender can send cells.
The following figure illustrates the relationship between PCR, SCR, MCR and MBS.
Chapter 5 WAN Setup
Prestige 861H Series User's Guide
74