Ethereal-dev: Re: [ethereal-dev] Re: [ethereal-users] CDP

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From: Guy Harris <guy@xxxxxxxxxx>
Date: Wed, 12 Jan 2000 11:42:26 -0800 (PST)
> Here is a file with a CDP packet, it now shows as LLC SNAP..Cisco..0x2000
> which is correct, but I guess it should show as CDP. The packet is recorded
> with Ethereal, not tcpdump (though there should be no difference now).

We used to treat all LLC SNAP packets, regardless of the OUI, as
encapsulated Ethernet packets, and we treat an Ethertype of 0x2000 as CDP.

We now treat only SNAP packets with an OUI of 0x000000 or Apple's OUI as
encapsulated Ethernet packets; other OUIs are handled separately.

I checked in a change to treat an OUI of 0x00000c and a protocol ID of
0x2000 as CDP.

If, in fact, all CDP packets are LLC SNAP packets with a Cisco OUI -
i.e., 0x2000 is *not* an Ethertype, it's a Cisco-proprietary protocol ID
- then we should probably make 0x2000 *not* be an Ethernet type.