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G/D/C/B/A-Series f/w 6.03 Use of the LLDP-MED Network-Policy TLV feature


Userlevel 3
Article ID: 12931

Products
G-Series, firmware 6.03.00.0022 and higher
D-Series, firmware 6.03.01.0008 and higher
C5-Series, all firmware
C3-Series, firmware 6.03.00.0022 and higher
B5-Series, all firmware
B3-Series, firmware 6.03.00.0022 and higher
A4-Series, firmware 6.61.02.0007 and higher

Goals
One of the new features cited in version 6.03 release notes, in the '
code:
What's New in 6.03
' section, is a new TLV (Type/Length/Value) option enhancement to LLDP-MED (7573):
[code]LLDP-MED Network-Policy TLV[/code]
code:
reduces deployment costs of VoIP deployments by enabling standards-based provisioning of VoIP phones. The switches can be configured to assign VLAN, QoS, rate-limiting, and others operational parameters for LLDP-MED enabled VoIP phones. When combined with Enterasys Policy at the edge, this is a powerful, low cost solution for deploying convergent networks.


This document discusses the concept of configuring to use the new feature, including a sample configuration.

Solution
The LLDP-MED Network-Policy TLV feature may be used to communicate some combination of VLAN, Priority, and/or DSCP value to an LLDP-MED-compliant IP Phone:
code:
set lldp port network-policy voice state enable tag tagged vid
<[code]vlan[/code]>
code:
cos
<[code]priority[/code]>
code:
dscp
<[code]dscp[/code]> <[code]ports[/code]>
code:
set lldp port tx-tlv med-pol sys-name port-desc
<[code]ports[/code]>

Note: If just activating the above-stated tx-tlv advertisements does not have the desired effect, then consider activating
code:
all
advertisement ('
code:
set lldp port tx-tlv all
<[code]ports[/code]>').

Recognizing that an IP Phone typically transmits its traffic VLAN-tagged while its attached PC's traffic is transmitted untagged, the phone would accept and utilize those same values in its VLAN Tag (VLAN, Priority) and IP Header (DSCP)(5811).

On the switch one might then configure Policy or DiffServ (5848) to interpret any incoming (probably DSCP) value to yield a Policy Role or DiffServ action. Since VLAN and Priority are directly assignable using Policy, it would make sense to advertise the VLAN and Priority via LLDP-MED only in the absence of Policy. However, this is totally up to the user, based on the network design.

Here, LLDP-MED would replace the possible use of CiscoDP to communicate a "VVID" (Voice VLAN ID) to the phone (5831). With CiscoDP, if the design calls for the phone to use a Priority or DSCP value, this requires phone configuration.

For more background regarding the LLDP command set, please refer to the Configuration Guide for your product and firmware line.

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