Wireshark · Wireshark-dev: Re: [Wireshark-dev] Patch to packet-eth.c to clarify address ig/lg bits

["ronnie sahlberg" <ronniesahlberg@xxxxxxxxx>]

ok   i removed those conditionals so it always dissects the bit.

to me it looks a bit funny to have the LG bit dissected and flagged
for broadcasts.   maybe we should ignore the LG bit for broadcast
packets?



On 8/25/06, Guy Harris <guy@xxxxxxxxxxxx> wrote:
> ronnie sahlberg wrote:
>
> > Only dissect the LG bit if it is a unicast address (i think this makes
> sense)
>
> I think there are both locally-administered and globally-administered
> group addresses.  IEEE 802-2001 says:
>
>  A 48-bit universal address consists of two parts. The first 24 bits
> correspond to the OUI as assigned by the IEEE, except that the assignee
> may set the LSB of the first octet to 1 for group addresses or set it to
> 0 for individual addresses. The second part, comprising the remaining 24
> bits, is administered by the assignee. In the 48-bit LAN MAC address, an
> example of which is shown in Figure 8, the OUI is contained in octets 0,
> 1, 2, and the value assigned by the assignee is contained in octets 3,
> 4, 5. This address, including its OUI, is used throughout this document
> as the basis for examples of LAN MAC addresses and protocol identifiers.
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