PLANET IGS-10020HPT User Manual

Page 310

User’s Manual of IGS-10020HPT

The page includes the following fields:

Fast start repeat count

Object

Description



Fast start repeat count

Rapid startup and Emergency Call Service Location Identification Discovery of

endpoints is a critically important aspect of VoIP systems in general.In addition, it

is best to advertise only those pieces of information which are specifically

relevant to particular endpoint types (for example only advertise the voice

network policy to permitted voice-capable devices), both in order to conserve the

limited LLDPU space and to reduce security and system integrity issues that can

come with inappropriate knowledge of the network policy.

With this in mind LLDP-MED defines an LLDP-MED Fast Start interaction

between the protocol and the application layers on top of the protocol, in order to

achieve these related properties. Initially, a Network Connectivity Device will only

transmit LLDP TLVs in an LLDPDU. Only after an LLDP-MED Endpoint Device is

detected, will an LLDP-MED capable Network Connectivity Device start to

advertise LLDP-MED TLVs in outgoing LLDPDUs on the associated port. The

LLDP-MED application will temporarily speed up the transmission of the

LLDPDU to start within a second, when a new LLDP-MED neighbor has been

detected in order share LLDP-MED information as fast as possible to new

neighbors.

Because there is a risk that a LLDP frame being lost during transmission

between neighbors, it is recommended to repeat the fast start transmission

multiple times to increase the possibility for that the neighbors has received the

LLDP frame. With Fast start repeat count it is possible to specify the number of

times the fast start transmission is repeated. The recommended value is 4 times,

giving that 4 LLDP frames with a 1 second interval will be transmitted, when a

LLDP frame with new information is received.

It should be noted that LLDP-MED and the LLDP-MED Fast Start mechanism is

only intended to run on links between LLDP-MED Network Connectivity Devices

and Endpoint Devices, and as such does not apply to links between LAN

infrastructure elements, including between Network Connectivity Devices, or to