Quality Of Service (Qos); Type Of Service (Tos); Diffserv; Dscp And Per-Hop Behavior - ZyXEL Communications P-2608HWL-Dx Series User Manual

P-2608HWL-Dx Series User's Guide
1 Pick up the phone and press "****" on your phone's keypad and wait for the message
that says you are in the configuration menu.
2 Press a number from 1301~1308 followed by the "#" key to delete the tone of your
choice. Press 14 followed by the "#" key if you wish to clear all your custom tones.
You can continue to add, listen to, or delete tones, or you can hang up the receiver when you
are done.

11.1.12 Quality of Service (QoS)

Quality of Service (QoS) refers to both a network's ability to deliver data with minimum delay
and the networking methods used to provide bandwidth for real-time multimedia applications.

11.1.12.1 Type Of Service (ToS)

Network traffic can be classified by setting the ToS (Type Of Service) values at the data
source (for example, at the ZyXEL Device) so a server can decide the best method of delivery,
that is the least cost, fastest route and so on.

11.1.12.2 DiffServ

DiffServ is a class of service (CoS) model that marks packets so that they receive specific per-
hop treatment at DiffServ-compliant network devices along the route based on the application
types and traffic flow. Packets are marked with DiffServ Code Points (DSCPs) indicating the
level of service desired. This allows the intermediary DiffServ-compliant network devices to
handle the packets differently depending on the code points without the need to negotiate
paths or remember state information for every flow. In addition, applications do not have to
request a particular service or give advanced notice of where the traffic is going.

11.1.12.3 DSCP and Per-Hop Behavior

DiffServ defines a new DS (Differentiated Services) field to replace the Type of Service
(TOS) field in the IP header. The DS field contains a 2-bit unused field and a 6-bit DSCP field
which can define up to 64 service levels. The following figure illustrates the DS field.

Figure 88 DiffServ: Differentiated Service Field

DSCP
(6-bit)
DSCP is backward compatible with the three precedence bits in the ToS octet so that non-
DiffServ compliant, ToS-enabled network device will not conflict with the DSCP mapping.
1. The ZyXEL Device does not support DiffServ at the time of writing.
158
Unused
(2-bit)
1
Chapter 11 SIP