Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 1907)

LLDP, LLDP-MED and Voice VLAN Introduction and Configuration
Software Reference for x310 Series Switches
C613-50046-01 REV A AlliedWare Plus TM Operating System - Version 5.4.4C 70.3
LLDP defines:
■ a set of common advertisements ( “LLDP Advertisements” on page 70.4 )
■ a protocol for transmitting and receiving advertisements ( “Transmission and
Reception” on page 70.8 )
■ a method for storing the information that is contained within received
advertisements (
“Storing LLDP Information” on page 70.10 )
Interactions LLDP has the following interactions with other switch features:
■ Spanning tree
Ports blocked by a spanning tree protocol can still transmit and receive LLDP
advertisements.
■ 802.1x
Ports blocked by 802.1x port authorization cannot transmit or receive LLDP
advertisements. If LLDP has stored information for a neighbor on the port before it
was blocked, this information will eventually time out and be discarded.
■ VLAN tagging
LLDP packets are untagged; they do not contain 802.1Q header information with
VLAN identifier and priority tagging.
■ Virtual Chassis Stacking (VCStack) resiliency link
When a port is configured as a VCStack resiliency link port, LLDP does not operate on
the port; LLDP neither transmits nor receives advertisements, and any LLDP
configuration and data stored for the port, including counters, is discarded.
■ Mirror ports
LLDP does not operate on mirror analyzer ports.
LLDP-MED
LLDP for Media Endpoint Devices (LLDP-MED), is an extension of LLDP used between LAN
network connectivity devices, such as this switch, and the media endpoint devices
connected to them, such as IP phones. LLDP-MED is specified in ANSI/TIA-1057-2006. Of
the application types specified in ANSI/TIA-1057-2006, the switch supports Application
Type 1: Voice.
LLDP-MED uses the LLDP advertisement, transmission and storage mechanisms, but
transmits, receives, and stores data specifically related to managing the voice endpoint
devices. This includes information about network policy, location, hardware configuration,
and, for Power over Ethernet-capable devices, power management.
Voice VLAN
Many IP phones (or other IP voice devices) have two interfaces: one to connect to the
network and another that allows a computer or similar device to connect to the network
via the IP phone. It is often desirable to treat the voice and data traffic separately so that
appropriate Quality of Service (QoS) policies can be applied to each. The Voice VLAN
feature uses LLDP-MED to convey configuration information (such as VLAN ID and User
Priority tagging, and DiffServ Code Point (DSCP)—
“Differentiated Services
Architecture” on page 38.4 ) for the voice traffic to the IP phone. In response, the IP
phone sends voice traffic according to this configuration. The data traffic coming through
the IP phone from the PC is sent with the default configuration, typically untagged with
normal priority.