Multi-Tech Systems MVPGSM-2 Field Name Values AutoCall/Offhook Alert Parameters, Dynamic Jitter

Chapter 4: Configuring your MVPGSM

Voice/Fax Parameter Definitions (continued)

Field Name Values

AutoCall/Offhook Alert Parameters

Auto Call / Offhook	AutoCall,
Alert

Generate Local Dial	Y/N
Tone
Offhook Alert Timer
Phone Number	--

Dynamic Jitter

Dynamic Jitter Buffer

Minimum Jitter Value	60 - 400ms
Maximum Jitter Value	60 - 400ms
Optimization Factor	0 - 12

Auto Disconnect

Automatic	--
Disconnection
Jitter Value	1-65535

Call Duration	1-65535
Consecutive Packets	1-65535
Lost
Network	1 to 65535
Disconnection

Description

The AutoCall option enables the local MultiVOIP GSM to call a remote SIP endpoint without the user having to dial a Phone Directory Database number. As soon as you access the local MultiVOIP GSM voice/fax channel, the MultiVOIP GSM immediately connects to the SIP end point identified in the Phone Number box of this option. This function requires an entry in the Outgoing phonebook of the local MultiVOIP GSM.

If selected, dial tone will be generated locally while the call is connecting between gateways. This would be useful if there is a long network delay.

This section is grayed-out as Offhook Alert is not used.

Phone number used for Auto Call function. This phone number must correspond to an entry in the Outbound Phonebook of the local MVPGSM.

Dynamic Jitter defines a minimum and a maximum jitter value for voice communications. When receiving voice packets from an SIP end point, varying delays between packets may occur due to network traffic problems. This is called Jitter. To compensate, the MVPGSM uses a Dynamic Jitter Buffer. The Jitter Buffer enables the MVPGSM to wait for delayed voice packets by automatically adjusting the length of the Jitter Buffer between configurable minimum and maximum values. An Optimization Factor adjustment controls how quickly the length of the Jitter Buffer is increased when jitter increases on the network. The length of the jitter buffer directly affects the voice delay between MultiVOIP GSM gateways.

The minimum dynamic jitter buffer of 60 milliseconds is the minimum delay that would be acceptable over a low jitter network. Default = 150 ms

The maximum dynamic jitter buffer of 400 milliseconds is the maximum delay tolerable over a high jitter network. Default = 300 ms

The Optimization Factor determines how quickly the length of the Dynamic Jitter Buffer is changed based on actual jitter encountered on the network. Selecting the minimum value of 0 means low voice delay is desired, but increases the possibility of jitter-induced voice quality problems. Selecting the maximum value of 12 means highest voice quality under jitter conditions is desired at the cost of increased voice delay. Default = 7.

The Automatic Disconnection group provides four options which can be used singly or in any combination.

The Jitter Value defines the average inter-arrival packet deviation before the call is automatically disconnected. The default is 300 milliseconds. A higher value means voice transmission will be more accepting of jitter. A lower value is less tolerant of jitter. Inactive by default. When active, default = 300 ms. However, value must equal or exceed Dynamic Minimum Jitter Value.

Call Duration defines the maximum length of time (in seconds) that a call remains connected before the call is automatically disconnected. Inactive by default. When active, default = 180 sec.

Consecutive Packets Lost defines the number of consecutive packets that are lost after which the call is automatically disconnected.

Inactive by default. When active, default = 30

Specifies how long to wait before disconnecting the call when IP network connectivity with the remote site has been lost. Default = 30 sec

Multi-Tech Systems, Inc. MVPGSM 32