Hi,
FF FF 00 00 0D 22 70 02 0A 00 00 00 00 00 00 02 43 00 01 43
02 0A is the linkest_header_t . The second byte, 0A, is a counter and
you can ignore it. The flags byte is 02.
The higher nibble (4 bits) of this byte are reserved, the lower nibble
is the number of link quality estimates in the footer. Thus, there are
2 link quality entries. "2" is the number of entries in the footer, it
is not its size in bytes. . The link estimator footer is:
typedef nx_struct linkest_footer {
neighbor_stat_entry_t neighborList[1];
} linkest_footer_t;
Here the author of the link estimator uses [1] as size of the array as
placeholder, but the array can be longer - and indeed it is in this
case. The footer is composed of 2 neighbor_stat_entry_t:
// for outgoing link estimator message
// so that we can compute bi-directional quality
typedef nx_struct neighbor_stat_entry {
nx_am_addr_t ll_addr;
nx_uint8_t inquality;
} neighbor_stat_entry_t;
In this example, the neighbor_stat_entry_t are 00 02 43 and 00 01 43.
The former represents the link quality for the node whose address is
00 02, the latter for the node whose address is 00 01.
Regards.
--
Giuseppe Cardone
On Thu, May 6, 2010 at 12:33 PM, Yusnaidi Md Yusof <[email protected]> wrote:
> Hi All,
>
> I not really understand what does the 'uint8_t flags' field means in the
> /tos/lib/net/4bitle/LinkEstimator.h file?
>
> In the file, the 'flags' is quoted as: "flags to describe the state of this
> entry".
>
> Based on my understanding, the 'flags' indicates the 'number of elements in
> the link estimator footer' which is the linkest_footer_t.
>
> If I have a CTP routing data sample such as like this (the sample data taken
> from the MViz program):
>
> FF FF 00 00 0D 22 70 02 0A 00 00 00 00 00 00 02 43 00 01 43
>
> therefore, the field '02' (which I highlighted),refers to the 'flags' field
> of the linkest_header_t. Thus, the last 6 bytes of the stream (00 02 43 00
> 01 43) would reflect this 'flags'.
> If I converted the hexa '02', that would be 2 decimal, which I conclude
> there will be two number of elements in the link estimator footer, but what
> I see here there are 6 bytes of them altogether??
>
> I am sure I missed a correct understanding here about the flags
> field...Please someone correct me...
>
> thanks in advance...
>
> Yusnaidi
>
>
>
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