Cisco Systems IPMUX-1, IPMUX-1E Ethernet Throughput in Dynamic CAS Mode

IPmux-1/1E Installation and Operation Manual Chapter 1 Introduction
Functional Description 1-21
Frame/second =
Unframed: 5447/n for a full E1
4107/n for a full T1
Framed: 8000 x k/(46.875 x n)
Where k = number of assigned timeslots
Where n = 48
ebytes/framTDM
The maximum Ethernet throughput in static mode is calculated by:
Unstructured
bits 8*
n*47
data
TS*8000
*)
size frame
(














++
48476
44444443444444421payloadoverhead frameVLAN
Structured
bits 8*
n*47
2
*500
pointer
1- 8)*(47
*8000
data
TS*8000
* )
size frame
(
























++
++
48476
48476
48476
44444443444444421
CAS
TSTS
payload overhead frameVLAN
• where VLAN is an optional field: if enabled it adds 4 bytes to the frame
overhead
• where payload = number of TDM bytes in frame, (48, 96, 144, 192, … 384)
• where frame overhead = size of 46 bytes, include MAC, LLC, IP and UDP
layer
• where CAS is signaling (note: for structured mode only)
• where TS is number of configured time slots.
The result in both the equations is in bits per second [bps].
Ethernet Throughput in Dynamic CAS Mode
Configuring the active time slot bytes parameter can reduce Ethernet throughput.
This parameter controls the number of TCM bytes encapsulated per time slot in a
frame. The range is 24 to 64 bytes.
A large number of time slots and a large active time slot bytes size can surpass the
maximum Ethernet frame size.
In dynamic CAS mode the throughput is variable, depending on the active time
slots as defined by the ABCD CAS bits.