Nortel Networks NN43001-314 - Manual (Page 378)

378 Appendix B Branch Office engineering example
1 Calculate the data rate:
Total traffic in Erlangs (from Page 439 ) x 95 kbps
22 x 95 kbps = 2090 kbps = 2.09 Mbps
One Erlang of TDM 64 kbps channel becomes 95 kbps packets
after G.711 codec transcoding, which adds overhead. See
Table 44
"LAN/WAN bandwidth for one channel (one Erlang)" (page 377) if
another type of codec is used.
Requirement: TLAN subnet bandwidth 2.02 Mbps
—End—
Procedure 50
Calculating MG 1000B with Virtual Trunk
LAN/WAN
Step Action
Assuming G.711/30 ms for the LAN/WAN, the traffic distribution is as follows:
1 Calculate the MC traffic:
MC traffic = 180 CCS
One MC is needed (794 CCS capacity).
2 Calculate the Virtual Trunk traffic:
IPPT traffic = 72 CCS
An equivalent of a 24-port channel (capacity 550 CCS from Table
43 "Traffic capacity at P.01, P.005, and P.001 GOS" (page 377) ) is
sufficient to handle the Virtual Trunk traffic.
3 Calculate the incremental LAN/WAN bandwidth:
a. LAN/WAN traffic = IT traffic to MOR + Analog traffic to IPPT
= 252 + 72
= 324 CCS
b. LAN/WAN bandwidth = 324/36 x 37 kbps (from Table 44
"LAN/WAN bandwidth for one channel (one Erlang)" (page 377)
for G.711 codec with 30 ms payload)
Nortel Communication Server 1000
Branch Office Installation and Commissioning
NN43001-314 01.02 Standard
Release 5.0 20 June 2007
Copyright © 2007, Nortel Networks
.