TANDBERG D13192 Dynamic playout buffering, Asymmetrical media capabilities, Latency & Jitter

Technical Description of TANDBERG Gateway with software version G2

An example of this is automatic adjustment of total bandwidth used when DuoVideo is opened.

4.1.5.3 Dynamic playout buffering

Shapes the incoming data for better playout and re-sequencing of packet delivered out of order. This ensures better lip sync.

4.1.5.4 Asymmetrical media capabilities

Audio and video protocols can be fully asymmetrical.

E.g., the TANDBERG Gateway can send H.263 and receive H.261 at the same time.

4.1.5.5 Diagnostic tools for IP

Q.931	To show Q.931 trace during a conference you need to issue the command syslog
	on. One can get traces for RAS, Q.931 and H.245 with this command. It is a
	complex trace and requires an extensive knowledge in H.323 signalling to be
	understood.
Ping	Ping is used to see if the TANDBERG Gateway is able to reach a specific IP-
	address, using a mechanism in IP called ICMP. If the TANDBERG Gateway is
	unable to register to its gatekeeper, or if it is unable to dial a specific endpoint,
	one can use ping to see if there is at least an IP-route to the gatekeeper or to the
	endpoint.
Traceroute	Traceroute does exactly that; it traces the route an IP-packet takes to reach its
	destination and displays all router hops. Traceroute is very useful for seeing
	exactly where there is a routing-problem in the IP-network, and for checking
	where transport-delay is introduced.

4.1.5.6 Latency & Jitter

Latency is defined as the time between a node sending a message and receipt of the message by another node. The TANDBERG Gateway can handle any value of latency- however, the higher the latency, the longer the delay in video and audio. This may lead to conferences with undesirable delays causing participants to interrupt and speak over each other.

Jitter is defined as the variation in latency for packets sent between two nodes in the network. Where constant latency simply produces delays in audio and video, jitter can have a more adverse effect. Jitter causes packets to arrive out of order or at the wrong times, which again leads to packet loss. The TANDBERG Gateway can manage packets with jitter up to 100ms. If excessive packet loss is detected, the TANDBERG Gateway will downspeed the connection until acceptable packet loss is achieved.

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