The 3300 ICP uses G.729a voice compression to reduce the bandwidth required for an IP call.
IP telephones are grouped into zones. The default zone (1) has intra-zone compression turned off. Other zones are created to allow for intra-zone compression at different settings. If a call originates in one zone and terminates in another, compression is used when available at both endpoints. If a call originates and terminates within the same zone, the configuration parameters determine whether or not compression is applied.
Note: For 3300 ICP Release 8.0 software and later, you can manage bandwidth through Call Admission Control. See Bandwidth Management Description for more information.
IP devices can be moved to different locations as long as they stay within the same network segment. If it is moved into a different compression zone, configuration must be modified or the incorrect compression settings may be used.
If an IP device is on the same LAN as the 3300 ICP it is normally placed in the default zone and calls between these IP devices are non-compressed. Occasionally, it is necessary to compress calls between IP phones within the same zone; therefore, zones can be configured to compress calls within it. If the IP device is located on a remote LAN segment and must connect over a WAN link to the system, it should be placed in a compression zone created for IP devices on that specific remote LAN.
Non-IP endpoints include any device on the system capable of originating or terminating a call, but does not support IP streaming (for example, analog telephones, TDM based digital telephones, ISDN trunks, voice mail ports, Music On Hold, Recorded Announcement Device, etc.). These devices are placed in the default compression zone (1). Calls made between IP phones in the default zone and a non-IP telephones/trunks are non-compressed. Calls made between non-IP telephones/trunks and IP devices in other compression zones are compressed when possible.
IP trunk routes can be configured to control whether calls using a specific route should be compressed. IP trunks between co-located systems would normally be configured for no compression while those between systems connected through a WAN would be configured for compression.
When a call is placed, the originating system determines if compression should be used based on the compression zone of the originating device and the compression setting of the IP trunk. When the destination system receives a compression request, it will attempt compression if it is not in the default compression zone. If compression is not possible the call will still be connected; although, without compression.
None. (See IP Networking/XNET Planning for IP Networking/XNET conditions.)
|
Condition |
Result |
|
Link to 3300 ICP system in the route is down |
Caller hears reorder tone, display shown as DPNSS leased line would |
|
No compression resource |
Call is connected without compression |
|
No TDM to IP resource |
Caller hears reorder tone |
|
Packet loss during call |
Low quality audio is experienced |
|
DPNSS timeout |
Call hears reorder tone, "ERROR" is displayed on telephone |
|
A call comes from Node 1, through Node 2, to Node 3, where: Node 1: 3300 ICP Release 5.0 or later with compression OFF. Node 2: 3300 ICP Release 4.1 or before with compression ON. Node 3: 3300 ICP Release 5.0 or later. |
The call is not compressed when going through Node 2. |
To program compression zones and configure IP devices for compression:
Plan the appropriate compression zones required for your networked system.
Station
Attributes form:
Enter the appropriate compression zone number in the Compression Zone
ID field (1 = default, no compression).
Network
Zones form:
Set the Intra-zone Compression field to "Yes"
when compression is preferred for calls within that zone.
Enter a descriptive label in the Label field.
