Specifications

Network Configuration Specifics
231
Sources that can be used to obtain network policy information
Table 68 indicates which LAN Policy parameters can be obtained from each of the different
sources of information.
Network configuration information and priorities
To obtain network configuration information such as IP addresses, L2 priority settings, L3 priority
settings and VLAN information the phones can be programmed manually or they can obtain
information via auto-discovery using LLDP-MED, CDP or DHCP mechanisms.
It is possible to program some network configuration information manually and obtain other
information via LLDP-MED, DHCP or CDP and also use default values.
The IP phone looks for VLAN setting information and network configuration information in a
specific priority order until all of the appropriate fields have been filled in. This priority order for
obtaining information is described in the following sections.
Table 68: Sources of Network Policy Information
Source of
Infor-
mation
Phone IP
Address
Default
Gateway
IP
Address
Subnet
Mask
VLAN
(802.1Q)
Information
L2 QOS
Priority
(802.1d/p)
L3 QOS
(DSCP)
RTC IP
Address
TFTP
Server IP
Address
DNS IP
Address
Manual
entry
Yes Yes Yes Yes Yes (0-6) Yes
(0-63)
Yes Yes Yes
LLDP-MED N/A N/A N/A Yes Yes (0-6) Yes
(0-63)
N/A N/A N/A
CDP
N/A N/A N/A Yes See Note 2 N/A N/A N/A N/A
DHCP Yes Yes Yes Yes, uses
double fetch
Yes (0-6) Yes
(0-63)
Yes Yes Yes
Default
Values
N/A N/A N/A No VLAN,
untagged
6 (If VLAN
via CDP
then default
is 5),
46
(Note)
N/A N/A N/A
Note 1: A DSCP value of 46 is recommended for newer installations using DSCP-aware routers. Value 46 will place the voice
into the Expedited Forwarding Queue (EF).
Note 2: Depending on certain network conditions the phone will use different DSCP default values. The default values under
specific conditions are:
• If the VLAN information was learnt via CDP, signalling will use a default DSCP value of ‘46’ and voice will use
a default DSCP value of ’46’. These values can be changed with additional programming.
• In situations where VLAN information cannot be learnt from either CDP or DHCP, the phone will use a DSCP
value of ‘0’ for both signalling and voice.