Uidelines For Remote Audio Device; Maximum Transfer Unit (Mtu); Communication Latency Requirements - 3Com NBX 100 Installation Manual

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Maximum Transfer
Unit (MTU)
Communication
Latency
Requirements
G
UIDELINES FOR
D C
EVICE
This appendix provides guidelines for connecting a remote audio device
®
to the NBX 100 system. The remote audio device can be an Business
Telephone, Analog Line card, Single-Port Analog Terminal Adapter (ATA),
Digital Line card, or other product.
The guidelines provided are for a single device, but the issues discussed
can be scaled to cover multiple devices. The guidelines include the
following topics.

Maximum Transfer Unit (MTU)

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Communication Latency Requirements

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Bandwidth Requirements
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Installing Fax Devices with ATAs
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The system requires that the interconnection mechanism provide an
apparent MTU of a full size IEEE 802.1 packet (1514 bytes of information
plus 4 byte CRC). The interconnection can fragment packets into smaller
frames but must reassemble the packets prior to delivery to any NBX 100
device. The NBX 100 devices do not presently support IP (or other) packet
fragmentation and reassembly.
The interconnect latency requirements can be broken into two main
categories: large packet latency and small packet latency. Depending on
the configuration of the interconnection mechanism, these latencies can
be quite different, often due to the interconnection device applying
compression to the packets. The compression function can increase
exponentially with packet size, resulting in very long delays for large
packets.
R
EMOTE
ONNECTIONS
A
UDIO