Dhcp Vlan Auto Discovery - Nortel 1120E Administration Manual

Rebinding interval
Provisioning server

DHCP VLAN Auto Discovery

Configuring a server for Voice VLAN Discovery is optional. This
configuration is done in addition to any configuration done for Full DHCP
or Partial DHCP and it is required only when you are configuring the VLAN
Auto Discovery in the Device Settings menu on the IP Phone 1120E.
Auto Voice VLAN Discovery is only possible in Full and Partial DHCP mode.
VLAN Auto Discovery configuration is useful in a network with separate
Data VLAN for traffic (commonly used for PC-to-PC communication) and
Voice VLAN for VoIP traffic with different priorities.
The VLAN Auto Discovery is a two-step process:
1. DISCOVER is sent to the DHCP server for available Voice VLAN IDs.
2. DISCOVER is sent to the DHCP server for all of the DHCP required
DHCP VLAN Auto Discovery requires a Nortel-SIP-Phone-aware
DHCP server. All DHCP requests carry the Vendor Class Identifier,
Nortel-SIP-Phone-A, to allow the DHCP server to identify that the requests
are coming from an IP Phone 1120E with SIP Firmware.
DHCP Auto Discovery returns Voice VLAN IDs. The DHCP protocol
provides no standard option for VLAN ID requests. Separate DHCP
vendor-specific entry is needed for DHCP VLAN Auto Discovery to convey
the VLAN information to the IP Phone. DHCP VLAN Auto Discovery
uses one of the reserved for site-specific use DHCP options for VLAN list
retrieval. At least one of the following Nortel site-specific options must be
returned by the DHCP server as part of each DHCPOFFER and DHCPACK
message for the IP Phone to accept these messages as valid; 43, 128, 131,
144, 157, 188, 191, 205, 219, 223, 232, 247, 251.
Copyright © 2008, Nortel Networks
.
Implementation varies
according to DHCP server.
Used for delivering the
provisioning server IP address.
This parameter can contain
either IP address or a URL to
the provisioning server or folder.
The DHCP server sends an OFFER with the available Voice VLAN IDs.
(If the Data VLAN ID has been manually provisioned in the Device
Settings of the IP Phone 1120E, DHCP DISCOVER is tagged with the
Data VLAN ID; otherwise, it is untagged.)
parameters. However, this DISCOVER is tagged with the Voice VLAN
obtained in step 1.
SIP Firmware Release 1.1 for IP Phone 1120E Administration
NN43112-300 02.03 Standard
27 May 2008
Full DHCP mode 61
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