292
A
PPENDIX
C: G
UIDELINES
FOR
R
EMOTE
A
UDIO
D
EVICE
C
ONNECTIONS
Large Packet Latency
The round-trip latency on large packets, 300 bytes to full MTU, must be
less than 450ms. The system will support an occasional packet delay of
450 to 900ms, but each such delay will cause retries and thus affect
bandwidth and performance. If delays in excess of 450ms occur at a
“high rate” (more than 1 every ~3 seconds) then system degradation can
occur, resulting in problems initializing (downloading devices) as well as
sluggish performance of system features.
Small Packet Latency
The round-trip latency on small packets, from 64 bytes up to the large
packet size, should be less than 100—150ms, to maintain a high quality
level of performance (this is especially significant in the quality of the
users’ conversations). Longer latency will not cause system failure but can
result in a large occurrence of “talk-over” situations within a
conversation. Additionally, the longer latency can cause the system to
appear sluggish during user interaction (dialing, answering, etc.).
Bandwidth
Requirements
The interconnect bandwidth requirements depend on the selected audio
compression and system configuration [Layer 2 or Layer 3 (IP)] topology.
Layer 2 Mulaw
(G.711) Audio
(Normal Setting)
The interconnection bandwidth requirements for a device configured as a
Layer 2 device running G.711 audio for each party in a conversation
requires a maximum of 73 Kbps. Thus, a point-to-point call requires this
peak bandwidth in each direction, while a 3-party conference requires a
peak of 219 Kbps in one direction. See Notes A and B.
Layer 3 Mulaw
(G.711) Audio
The overhead for running a device as a Layer 3 device results in a
maximum bandwidth requirement of 86 Kbps per party in the
conversation. Thus, a point-to-point call requires this peak bandwidth in
each direction, while a 3-party conference requires a peak of 258 Kbps in
one direction. See Notes A and B.
Layer 2 ADPCM Audio
(Reduced Bandwidth
Setting)
The interconnection bandwidth requirements for a device configured as a
Layer 2 device running ADPCM audio for each party in a conversation
requires a maximum of 42 Kbps. Thus, a point-to-point call requires this
peak bandwidth in each direction, while a 3-party conference requires a
peak of 126 Kbps in one direction. See Notes A and B.
Summary of Contents for NBX 100
Page 1: ...http www 3com com NBX 100 Installation Guide Release 2 8 Part No 900 0026 01 November 2000 ...
Page 12: ......
Page 18: ...18 ABOUT THIS GUIDE ...
Page 128: ...128 CHAPTER 2 CONFIGURING THE DIAL PLAN ...
Page 196: ...196 CHAPTER 4 CONFIGURING NBX 100 SYSTEM LEVEL SETTINGS ...
Page 238: ...238 CHAPTER 6 SETTING UP USERS AND FEATURES 6 Click Apply to effect the changes 7 Click OK ...
Page 268: ...268 CHAPTER 7 CONFIGURING DIGITAL LINE CARDS T1 E1 AND BRI CARDS ...
Page 286: ...286 APPENDIX A NBX 100 SYSTEM SPECIFICATIONS ...
Page 290: ...290 APPENDIX B T1 AND ISDN PRI SERVICES CIRCUIT PROVISIONING ...
Page 294: ...294 APPENDIX C GUIDELINES FOR REMOTE AUDIO DEVICE CONNECTIONS ...
Page 306: ...306 INDEX ...