Vidipac VSW7242, Руководство пользователя

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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
neighbour has been detected in order share LLDP-MED information as fast as possible to new
neighbours.
Because there is a risk of an LLDP frame being lost during transmission between neighbours, it is
recommended to repeat the fast start transmission multiple times to increase the possibility of the
neighbours receiving the LLDP frame. With Fast start repeat countit is possible to 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.
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 Network Connectivity Devices, or
other types of links.
Coordinates Location
Latitude
Latitude Should be normalized to within 0-90 degrees with a maximum of 4 digits.
It is possible to specify the direction to either North of the equator or south of the equator.
Longitude
Longitude Should be normalized to within 0-180 degrees with a maximum of 4 digits.
It is possible to specify the direction the either East of the prime meridian or West of the prime meridian.
Altitude
Altitude SHOULD be normalized to within -32767 to 32767 with a maximum of 4 digits.
It is possible to select between two altitude types (floors or meters).
Meters: Representing meters of Altitude defined by the vertical datum specified.
Floors: Representing altitude in a form more relevant in buildings which have different floor-to-floor
dimensions. An altitude = 0.0 is meaningful even outside a building, and represents ground level at the
given latitude and longitude. Inside a building, 0.0 represents the floor level associated with ground
level at the main entrance.
Map Datum
The Map Datum is used for the coordinates given in these options:
WGS84: (Geographical 3D) - World Geodesic System 1984, CRS Code 4327, Prime Meridian Name:
Greenwich.