Technical Description of TANDBERG 8000 with software version E3/B8
D12008 Rev. 11
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ISDN Downspeeding
will be started when one of the following actions occurs:
1.
Fallback to 2xH221 call when no BONDING framing is found
2.
Non-matching number of channels (N) during BONDING setup (e.g. N=4 on site A,
N=6 on site B)
3.
Downspeeding during call setup caused by a channel that won't connect
4.
Disconnect and downspeed if a channel won't sync
5.
Downspeeding when detecting B-channels that are looped
6.
Downspeeding if a channel drops during the call
The TANDBERG system will also start the BONDING synchronization procedure if there is a
long fatal failure situation:
7.
Extended loss of H221 framing
8.
Continuous BCH framing error in the video stream. If then a channel fails to sync, it will
be disconnected (as mentioned in 4.)
‘Downspeeding’ on IP:
The TANDBERG system has a similar way of ‘downspeeding’ on IP, described as follows:
a)
If system gets more than 10% packet loss during the last 2 seconds, it will go down 64
kbps. (Ex. Call set up on 768 kbps and the above packet loss occurs, the new callrate
will be 768 kbps – 64 kbps = 704 kbps).
b)
If after the next 2 seconds, there is still more than 10% packet loss, system will
‘downspeed’ 64 kbps again.
c)
The above will happen until call rate of 192 kbps is reached.
d)
If still same packet loss at 192 kbps the system will ‘upspeed’ back to original call rate
(since when in this situation, one may assume that the packet loss is due to other reasons
and not the H.323 call itself).
Different from the ISDN downspeeding, the system will not change Audio and Video
algorithms during the ‘downspeeding’ of an IP call. (See also chapter on IPLR).
4.1.7
Network Profiles
The TANDBERG 8000 has 3 fixed and 3 programmable Name, Prefix and Protocol settings that
may be used when dialling.
The system will automatically make an H.320 call if the dialled number is an ISDN number or
an H.323 call if an IP address is dialled. H.323 will also be selected if number prefix is
matching the H.323 prefix and the system is registered to a gatekeeper.