Chapter 1 Introduction IPmux-1/1E Installation and Operation Manual
1-22 Functional Description
The maximum Ethernet throughput in dynamic CAS mode is calculated by:
[(payload
8000 ) x ((payload+ 4) x TS) + 4 + frame overhead] x 8 bits
• where frame overhead is 46 bytes, including MAC, LLC, IP, and UFP layers
• where TS = number of configured time slots
• where payload = number of active time slot bytes per frame (24 to 64)
The frame overhead does not include:
• Preamble field: 7 bytes
• SFD field: 1 byte
• Interframe gap: 12 bytes
• VLAN field (when used): 4 bytes.
Ethernet Throughput in CESoIP Mode
Configuring the packet delay and the number of time slots controls the Ethernet
throughput. The range of the packet delay is 3 to 127 msec.
A large number of time slots and a long packet delay can surpass the maximum
Ethernet frame size.
The maximum Ethernet throughput in CESoIP mode is calculated by:
[( delay packet
1000 ) x (( 8
delay packet ) x TS) + 12 + frame overhead] x 8 bits
• where frame overhead is 46 bytes, including MAC, LLC, IP, and UFP layers
• where TS = number of configured time slots:
for an unframed E1 interface = 32
for an unframed E1 interface = 24
• where packet delay = 3 to 127.
Round Trip Delay The voice path round-trip delay is a function of all connections and network
parameters. The calculation for E1/T1 in each connection mode is described in the
following sections.
Note