2.2.2. DHCPv4 GeoLoc Option
The format of the DHCPv4 GeoLoc Option is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Code 144 | Length | LatUnc | Latitude +
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Latitude (cont'd) | LongUnc | +
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Longitude |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AType | AltUnc | Altitude +
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Alt.(cont'd) |Ver| Res |Datum|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Code: 8 bits. The code for the DHCPv4 GeoLoc Option (144).
Length: 8 bits. The length of the option, in octets.
For version 1, the option length is 16.
LatUnc: 6 bits. When the Ver field = 1, this field represents
latitude uncertainty. The contents of this field are
undefined for other values of the Ver field.
Latitude: A 34-bit fixed-point value consisting of 9 bits of
integer and 25 bits of fraction, interpreted as described
in Section 2.3.
LongUnc: 6 bits. When the Ver field = 1, this field represents
longitude uncertainty. The contents of this field are
undefined for other values of the Ver field.
Longitude: A 34-bit fixed-point value consisting of 9 bits of
integer and 25 bits of fraction, interpreted as described
in Section 2.3.
AType: 4 bits. Altitude Type, defined in Section 2.4.
AltUnc: 6 bits. When the Ver field = 1, this field represents
altitude uncertainty. The contents of this field are
undefined for other values of the Ver field.
Altitude: A 30-bit value defined by the AType field, described in
Section 2.4.
Ver: The Ver field is 2 bits, providing for four potential
versions. This specification defines the behavior of
version 1. The Ver field is always located at the same
offset from the beginning of the option, regardless of
the version in use.
Res: 3 bits. The Res field is reserved. These bits have been
used by [IEEE-802.11y], but are not defined within this
specification.
Datum: 3 bits. The Map Datum used for the coordinates given in
this option.
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