ZyXEL Communications V300 - Manual (Page 111)

Chapter 10 SIP Account Setup
V300 User’s Guide
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10.1.10.3 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 122 DiffServ: Differentiated Service Field
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.
The DSCP value determines the forwarding behavior, the PHB (Per-Hop Behavior), that each
packet gets across the DiffServ network. Based on the marking rule, different kinds of traffic
can be marked for different priorities of forwarding. Resources can then be allocated
according to the DSCP values and the configured policies.
10.1.10.4 VLAN
Virtual Local Area Network (VLAN) allows a physical network to be partitioned into multiple
logical networks. Only stations within the same group can communicate with each other.
Your V300 can add IEEE 802.1Q VLAN ID tags to voice frames that it sends to the network.
This allows the V300 to communicate with a SIP server that is a member of the same VLAN
group. Some ISPs use the VLAN tag to identify voice traffic and give it priority over other
traffic.
10.2 SIP Screens
10.2.1 SIP Settings Screen
Use this screen to maintain basic information about each SIP account. Your VoIP service
provider (the company that lets you make phone calls over the Internet) should provide this.
You can also enable and disable each SIP account. To access this screen, click VoIP > SIP >
SIP Settings.
DSCP
(6-bit) Unused
(2-bit)