NEC SV8500, Manual

Page: 46 / 3438

INTRODUCTION
INT-20
ToS (Type of Service)
Type of Service (ToS) is 1-byte data field used in IP packet. ToS value is used to assign priorities to IP packets
that are exchanged in a network for QoS Control. DiffServ and IP Precedence are typical QoS Control Technics.
QoS (Quality of Service)
Quality of Service guarantees network bandwidth and availability for applications. QoS is defined as the collec-
tive effect of service performance parameters, determining the degree of satisfaction of a user of the service and
is defined from the point of view of the service user.
Jitter Buffer
Jitter is a variation in delay of receiving IP packets. This is caused by various factors such as network congestion,
variable packet size, insufficient bandwidth. Jitter Buffer can reduce this problem by storing the received pack-
ets temporarily in buffer memory. By using this buffer the received packets can be conveyed to the higher ap-
plication. However, too much buffer size may cause delay.
CODEC (Coder/Decoder)
A codec is a module that is used for Analog/Digital conversion of video or audio data. The system uses the fol-
lowing codecs.
Static Routing
Routing table of router is manually created by the network administrator. When the network configuration is
changed, the administrator must change the routing table of each network device. However, Static Routing does
not have to exchange routing information between routers. Therefore, this routing does not reduce the band-
width of WAN. Static routing is used for a comparatively small-sized network.
CODEC BIT RATE REMARKS
G.711 64 kbps PCM
G.711

law (FEC) 64 kbps PCM
G.711 A law (FEC) 64 kbps PCM
G.722 48/56/64 kbps SB-ADPCM
G.722 (FEC) 48/56/64 kbps SB-ADPCM
G.723.1 6.3 kbps MP-MLQ
5.3 kbps ACELP
G.729 a 8 kbps CS-ACELP
G.729a (FEC) 8 kbps CS-ACELP
AMR-NB 4.75 ~ 12.2 kbps
(8 patterns)
ACELP
AMR-WB 6.60 ~ 23.85 kbps
(9 patterns)
ACELP
AMR-NB (FEC) 4.75 ~ 12.2 kbps
(8 patterns)
ACELP
AMR-WB (FEC) 6.60 ~ 23.85 kbps
(9 patterns)
ACELP