Cisco Systems IPMUX-1E operation manual Ethernet Throughput, Intrinsic PDV in Dynamic CAS Mode

Chapter 1 Introduction IPmux-1/1EInstallation and Operation Manual

Intrinsic PDV in Dynamic CAS Mode

I.PDV (ms) = active time slot bytes in frame X 0.125

Active time slot bytes in frame is the number of bytes per active time slot that will be sent on every frame transmitted over the Ethernet.

Intrinsic PDV in CESoIP Mode

The value of the packet delay configuration is user-defined.

Ethernet Throughput

Higher throughput reduces the IP/Ethernet overhead segment of the total packet and thus can significantly reduce the total Ethernet throughput.

On the other hand, packetization delay and intrinsic packet delay variation (PDVT) are increased; this contributes to a higher end-to-end delay. This effect can be small and negligible when a full E1 (or many timeslots) are transferred, but can be very significant when few timeslots are transferred. In this case, the packetization delay and the intrinsic PDV when configuring a large value of TDM bytes/frame can be very large and may exceed the maximum PDVT (jitter) buffer on the receiving end.

Ethernet Throughput in Static Mode

Configuring the TDM bytes per frame (TDM bytes/frame) parameter can reduce Ethernet throughput (bandwidth or traffic traveling through the Ethernet). This parameter controls the number of TDM bytes encapsulated in one frame.

The TDM bytes/frame parameter can be configured to n x 48 bytes where n is an integer between 1 and 30.

To calculate Ethernet throughput and intrinsic PDV as a function of

TDM bytes/frame:

Ethernet load (bps) =

[(frame overhead (bytes) + TDM bytes/frame) x 8] x frames/second Frame overhead = Ethernet overhead + IP overhead = 46 bytes

Note The frame overhead does not include:

•Preamble field: 7 bytes

•SFD field: 1 byte

•Interframe gap: 12 bytes

•VLAN field (when used): 4 bytes.

1-20 Functional Description