User’s Manual of GS-4210-16T2S_24T2S_16P2S_24P2S_48T4S
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4.12.6 MED Network Policy
Network Policy Discovery enables the efficient discovery and diagnosis of mismatch issues with the VLAN configuration, along
with the associated Layer 2 and Layer 3 attributes, which apply for a set of specific protocol applications on that port. Improper
network policy configurations are a very significant issue in VoIP environments that frequently result in voice quality degradation
or loss of service.
Policies are only intended for use with applications that have specific 'real-time’ network policy requirements, such as interactive
voice and/or video services.
The network policy attributes advertised are:
1. Layer 2 VLAN ID (IEEE 802.1Q-2003)
2. Layer 2 priority value (IEEE 802.1D-2004)
3. Layer 3 Diffserv code point (DSCP) value (IETF RFC 2474)
This network policy is potentially advertised and associated with multiple sets of application types supported on a given port.
The application types specifically addressed are:
1. Voice
2. Guest Voice
3. Softphone Voice
4. Video Conferencing
5. Streaming Video
6. Control/Signaling (conditionally support a separate network policy for the media types above)
A large network may support multiple VoIP policies across the entire organization, and different policies per application type.
LLDP-MED allows multiple policies to be advertised per port, each corresponding to a different application type. Different ports
on the same Network Connectivity Device may advertise different sets of policies, based on the authenticated user identity or
port configuration.
It should be noted that LLDP-MED is not intended to run on links other than between Network Connectivity Devices and
Endpoints, and therefore does not need to advertise the multitude of network policies that frequently run on an aggregated link
interior to the LAN.
The Voice Auto Mode Configuration, Network Policy Configuration and LLDP MED Network Policy Table screen in
Figure
4-12-18
and
Figure 4-12-19
appear.
