Chapter 3 - Administration
Administration Manual (H.323 Version)
AT-VP504E FXO
37
Quality of Service
Settings
QoS (Quality of Service) features enable network managers to decide
on packet priority queuing. QoS is the ability of a network element (e.g.
an application, host or router) to have some level of assurance that its
traffic and service requirements can be satisfied.
There are a number of characteristics that qualify QoS, including:
minimizing delivery delay
minimizing delay variations
providing consistent data throughput capacity
Differentiated
Services
(DiffServ)
Section
Differentiated Services (DiffServ, or DS) is a protocol for specifying and
controlling network traffic by class so that certain types of traffic get
precedence – for example, voice traffic, which requires a relatively
uninterrupted flow of data, might get precedence over other kinds of
traffic.
Unlike the earlier mechanisms of 802.1p tagging and Type of Service
(ToS), Differentiated Services avoids simple priority tagging and
depends on more complex policy or rule statements to determine how
to forward a given network packet. An analogy is made to travel
services, in which a person can choose among different modes of
travel – train, bus, airplane – degree of comfort, the number of stops on
the route, standby status, the time of day or period of year for the trip,
and so forth.
For a given set of packet travel rules, a packet is given one of 64
possible forwarding behaviors – known as per hop behaviors (PHBs).
A six-bit field, known as the Differentiated Services Code Point
(DSCP), in the Internet Protocol (Internet Protocol) header specifies
the per hop behavior for a given flow of packets. The DS field structure
is presented below:
0
1
2
3
4
5
6
7
+---+---+---+---+---+---+---+---+
| DSCP
|
CU
|
+---+---+---+---+---+---+---+---+
DSCP: Differentiated Services CodePoint.
CU: Currently Unused. The CU bits should always be set
to 0.
Summary of Contents for AT-VP504E FXS
Page 1: ...AT VP504E FXO H 323 Administration Manual PN 990 11592 10 Rev C VoIPTalk...
Page 16: ...Chapter 1 Introducing the AT VP504E FXO Administration Manual H 323 Version AT VP504E FXO 8...
Page 76: ...Chapter 5 Software Upgrade Administration Manual H 323 Version AT VP504E FXO 68...
Page 100: ...Appendix C Gatekeeper Registration Logic Administration Manual H 323 Version AT VP504E FXO 92...
Page 112: ...Index Administration Manual H 323 Version AT VP504E FXO 104...
