tcpdump mailing list archives
Re: proposal: rename DLT_PRISM_HEADER
From: David Young <dyoung () ojctech com>
Date: Wed, 18 Dec 2002 16:52:11 -0600
On Wed, Dec 18, 2002 at 03:56:36PM -0500, Solomon Peachy wrote:
With LTVs, your tcpdump may skip records whose type it does not know.No, the old DLT_IEEE80211_PRISM type did that; whet you end up with is a header twice as long that can't be parsed or constructed as easily and quickly.
What can we afford in terms of header length and CPU cycles spent parsing? I don't know what the outer acceptable figures are. How do you think those considerations weigh against the conveniences of LTVs I mention? In any case, I will reluctantly adopt the present format with unspecified mactime units. I will *gladly* adopt the format if the units for mactime are fixed at nanosecond resolution or higher, or given by a new header field. It is counter to the purpose of a unified radio header format to let the units change from one adapter to another. BTW, since you've got that 64-bit field for mactime, it does not make sense to use less than nanosecond resolution. Consider that a 64-bit field with nanosecond resolution provides for measuring the arrival time of a packet sent at 54Mbps to higher resolution than you will likely ever need (less than one "bit time"), for longer (584 years) than you will ever monitor a channel. Dave -- David Young OJC Technologies dyoung () ojctech com Engineering from the Right Brain Urbana, IL * (217) 278-3933 - This is the TCPDUMP workers list. It is archived at http://www.tcpdump.org/lists/workers/index.html To unsubscribe use mailto:tcpdump-workers-request () tcpdump org?body=unsubscribe
Current thread:
- Re: proposal: rename DLT_PRISM_HEADER, (continued)
- Re: proposal: rename DLT_PRISM_HEADER Guy Harris (Dec 11)
- Re: proposal: rename DLT_PRISM_HEADER Guy Harris (Dec 11)
- Re: proposal: rename DLT_PRISM_HEADER Guy Harris (Dec 11)
- Re: proposal: rename DLT_PRISM_HEADER Guy Harris (Dec 16)
- Re: proposal: rename DLT_PRISM_HEADER Solomon Peachy (Dec 16)
- Re: proposal: rename DLT_PRISM_HEADER Guy Harris (Dec 16)
- Re: proposal: rename DLT_PRISM_HEADER David Young (Dec 16)
- Re: proposal: rename DLT_PRISM_HEADER Guy Harris (Dec 16)
- Re: proposal: rename DLT_PRISM_HEADER David Young (Dec 18)
- Re: proposal: rename DLT_PRISM_HEADER Solomon Peachy (Dec 18)
- Re: proposal: rename DLT_PRISM_HEADER David Young (Dec 18)
- Re: proposal: rename DLT_PRISM_HEADER Solomon Peachy (Dec 18)
- Re: proposal: rename DLT_PRISM_HEADER David Young (Dec 19)
- Re: proposal: rename DLT_PRISM_HEADER Guy Harris (Dec 17)