Mitel 5560 IPT none Specifications download pdf (Page 70)

Engineering Guidelines

Provisioning for Traffic

All 3300 ICP controllers contain an internal TDM switching fabric. Calls between TDM sets, or

from TDM sets to trunks, will stay within this TDM switch. Calls between IP phones stream their

voice packets directly over the data network without going into the TDM domain in the 3300

ICP controller, but calls between IP sets and TDM devices (including both lines and trunks)

must go from the IP domain to the TDM switch fabric through the TDM gateway (E2T processor).

All of these calls require bandwidth or channels within the various domains and may require

specific resources (DSP tone generators and detectors, echo cancellation, etc.) within the

controller. The provisioning of these resources is done using the standard type of traffic analysis.

The TDM switching fabric in all of the 3300 ICP controllers is non-blocking, but the limitations

in the number of channels available in the number of channels available in the TDM gateway,

the fiber interfaces, and other resources mean that the system itself is not.

Under most ordinary conditions, the “rules of thumb” provisioning suggested in previous

sections gives a good estimate of the resources required for the number of lines (users) and

trunks in a system. For systems that are approaching the limits of the system, more detailed

calculations may be required through Customer Engineering Services.

Traffic analysis considerations:

• 36 CCS = 1 erlang (1 e) = 3600 call seconds during the busy hour.

• Call rates (CPH) and duration may vary from business to business. It may be necessary to

monitor a business to get more accurate values.

• Typical phone calls are 100 seconds in duration.

• Typically, a normal office phone is busy 16% of the time, or 0.16 e, or 6 CCS (this is 6 CPH

@ 100 seconds, i.e. 600 call seconds or 6 centum call seconds or 10 minutes).

• Typically, a hotel phone is busy 6% of the time, or 0.06 e, or 2 CCS.

• Typically, a busy office phone, such as one handling dispatch orders, can be busy 33% of

the time, or 0.33 e, or 12 CCS.

OpenPhone 26/27 14

SpectraLink NetLink 14

Telematrix 3000IP 12

Note: The default number of programmable keys on the 5560IPT is 96 keys. This can

be increased to 192 keys with a license selection. This can only be applied to a system

that is configured with up to 700 users.

Table 22: Programmable Key Capacity by Device Type

Phone Type Programmable Keys

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Mitel 5560 IPT none Specifications Page 70