User's Manual

as part of each DHCPOFFER and DHCPACK message for the IP Deskphone to accept these
messages as valid; 43, 128, 131, 144, 157, 188, 191, 205, 219, 223, 232, 247, 251.
After multiple VLAN IDs are returned from the DHCP server, the IP Deskphone tries to connect
to each of the VLANs, following the order in which VLAN IDs are specified in the DHCP
option.
The format of the field for DHCP VLAN Auto Discovery is: Type, length, and data, described
in the following sections.
Type (1 octet)
To avoid the possibility of option types already being used by different vendors, there are
fourteen options types supported by the IP Deskphone. They are: 128, 131, 144, 157, 188,
191, 205, 219, 223, 232, 247, 251, 247, and 251. Select one value from the type byte list for
the DHCPOFFER response. Avaya recommends using 232, 247, or 251. DHCP option
numbers less than 224 are reclaimed by the IETF (RFC3942). Future changes in the DHCP
protocol can force the IP Deskphone to stop sending these option requests. Currently, IP
Deskphone with SIP Software does support the remaining listed options to maintain backward
compatibility.
Length (1 octet)
The Length value is variable. Count only the number of octets in the data field.
Data (variable number of octets)
ASCII based format: VLAN-A:XXX+YYY+ZZZ. where, VLAN– A: uniquely identifies this as the
Avaya DHCP VLAN discovery request. Each VLAN ID is followed by a plus (+) sign if there
are more VLAN IDs or a period (.) to terminate the string.
There are a maximum of 10 VLAN IDs that can be configured in the current version.
Once IP Deskphone with SIP Software receives the DHCP offer containing the site-specific
Voice VLAN option, the next DHCPDISCOVERY message is tagged with the Voice VLAN
ID.
Configure the DHCP Server
112 SIP Software for Avaya 1100 Series IP Deskphones-Administration November 2012
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