As I mentioned at the mic during yesterday's meeting, UDP checksum=0 is used/seen quite a bit in RTP traffic. Clearly VoIP was rather in its infancy in 1999 when that study was done. And to be frank, I rather doubt SIP will successfully work through inline v4-v6 translators anyway, so I'm not sure it actually matters much to y'all if RTP uses checksum=0.
However, I just checked some wireshark traces, and apparently even emule/edonkey p2p sends UDP checksum=0 from some hosts. I can provide the trace if anyone wishes to see it. And considering that was only the second wireshark trace I went to look for when trying to find an example of checksum=0, this may be more common than one may think. (or I'm lucky) -hadriel > -----Original Message----- > From: behave-boun...@ietf.org [mailto:behave-boun...@ietf.org] On Behalf > Of Hesham Soliman > Sent: Tuesday, July 28, 2009 8:45 AM > > > > 'in the sample taken by one researcher' > > > > (where's the actual email/research/numbers? > > [MILLER] G. Miller, Email to the ngtrans mailing list on 26 March > > 1999. > > doesn't say actually) > > > > I have some dns packets at least that aren't checksumed and do > > traverse a wide-area-network. The work referenced is from at least 10 > > years ago, certainly things have changed, we can hope they changed in > > the positive direction, but it's not clear to me that that is the > > case. > > => Can you point to another study? If not, then I'd rather take that one > researcher's study than nothing, or worse, change IPv6 implementations > > Hesham > > > > > Google searching provides the email which says (among other things) > > (ftp://ftp.ietf.org/ietf-mail-archive/ngtrans/1999-03.mail) > > > > From Greg Miller (mci.net) > > "I just did a little analysis on the UDP checksum issue. This is by no > means a > > comprehensive study, but I hope it's better than nothing. (To give > credit > > where it's due, Bill Kroah, a colleague here did lots of the number > > crunching.)" > > > > and: (erik nordmark) > > "I'm unsure of the operational implications. > > It would be great if we could determine the amount of UDP Internet > traffic > > (outside a single or a few LANs) that don't use UDP checksums today. > > > > At a minimum we need to list this issue in the draft - I don't know > > if we need to support it." > > > > original poster lost in time: > > "The memo says that no cheksum update is necessary for UDP. But we > > think this is not ture. There is one exception. > > > > If a UDP/IPv4 packet whose checksum is 0(ie. not calculated), SIIT > > have to calculate checksum for a new UDP/IPv6 packet." > > > > It seems that the case hasn't been refreshed/touched in ~10 years, so > > saying now that 'eh, just toss away the packets...' is a little > > cavalier. > > > > -chris > > -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
