TCH group BC840-MC series, User Manual

Page: 106 / 155

Item Description
DSCP field Range: [0...63]. DSCP (Differentiated Services Code Point) uses the
first 6 bits of the ToS (Type of Service) field in the header of IP
packets for packet classification purposes. The bit pattern in the field
indicates the type of service and forwarding behavior at the next node.
With 26 bits, up to 64 network service types can be defined. RFC 2724
(see - http://www.ietf.org/rfc/rfc2474.txt) describes the Differentiated
Services (DS) field and the DiffServ Code Point. See also the note on
Differentiated Services later in this chapter.
Default multicast
IP address Destination IP address for multicast sessions.
Default multicast
IP port Port number for multicast sessions.
Note on Differentiated Services: Differentiated Services (DiffServ, or DS) is a method for
adding QoS (Quality of Service) to IP networks. In routed networks, critical network traffic
such as video and audio streams, which require a relatively uninterrupted flow of data, can
get blocked due to other traffic. DiffServ can be used to classify network traffic and give
precedence - i.e. low-latency, guaranteed service - to high-priority traffic, while offering
best-effort service to non-critical traffic such as file transfers or web traffic.
Each stream has a DSCP (Differentiated Services Code Point) field in the IP header. Routers
will identify the network service type in the DSCP field and provide the appropriate level of
service. Low-latency service can be realized, for example, through priority queuing,
bandwidth allocation, or by assigning dedicated routes.
Note on RTP and RTCP: The Real-time Transport Protocol (RTP) is designed for end-to-end
real-time, audio or video data flow transport. It is regarded as the primary standard for
video/audio transport over multicast or unicast network services. RTP does not provide
guaranteed delivery, but sequencing of the data makes it possible to detect missing packets.
It allows the recipient to compensate for breaks in sequence that may occur during the
transfer on an IP network. Error concealment can make the loss of packets unnoticeable.
RTP is usually used in conjunction with the Real-time Transport Control Protocol (RTCP). RTP
carries the media streams. RTCP provides reception quality feedback, participant
identification and synchronization between media streams.
12.3.8 SAP Settings
Audio > Advanced > SAP Settings
Audio
106