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CHAPTER 2: SYSTEM
Parameter 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 that 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 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 to share LLDP-MED
information as fast as possible to new neighbors.
Because there is a risk of an LLDP frame being lost during transmission between neighbors, we recommend that you repeat the
fast start transmission multiple times to increase the possibility of the neighbors receiving the LLDP frame. With Fast start repeat
count, you can specify the number of times the fast start transmission would be repeated. The recommended value is 4 times,
given that 4 LLDP frames with a 1 second interval will be transmitted when an LLDP frame with new information is received.
NOTE: The 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 does not apply to links between LAN infrastructure elements, including Network
Connectivity Devices, or other types of links.
Transmit TLVs
Port: The interface name to which the configuration applies.
Capabilities: When checked, the switch’s capabilities are included in LLDP-MED information transmitted.
Policies: When checked the configured policies for the interface are included in LLDP-MED information transmitted.
Location: When checked the configured location information for the switch is included in LLDP-MED information transmitted.
Device Type: Any LLDP-MED Device is operating as a specific type of LLDP-MED Device, which may be either a Network
Connectivity Device or a specific Class of Endpoint Device, as defined below.
– A Network Connectivity Device is an LLDP-MED Device that provides access to the IEEE 802 based LAN infrastructure for LLDP-
MED Endpoint Devices.
– An LLDP-MED Network Connectivity Device is a LAN access device based on any of the following technologies:
1. LAN Switch/Router
2. IEEE 802.1 Bridge
3. IEEE 802.3 Repeater (included for historical reasons)
4. IEEE 802.11 Wireless Access Point
5. Any device that supports the IEEE 802.1AB and MED extensions that can relay IEEE 802 frames via any method.
– An Endpoint Device is an LLDP-MED Device that sits at the network edge and provides some aspect of IP communications
service, based on IEEE 802 LAN technology.
– The main difference between a Network Connectivity Device and an Endpoint Device is that only an Endpoint Device can start
the LLDP-MED information exchange.
– Even though a switch always should be a Network Connectivity Device, you can configure it to act as an Endpoint Device,
and thereby start the LLDP-MED information exchange (In the case where two Network Connectivity Devices are connected
together).
