In message <1681359.zi93O8g9E0@tums.local>, Paul Vixie writes:
> On Tuesday, July 4, 2017 8:29:53 PM GMT Ray Bellis wrote:
> > My argument against using an NSEC style bitmap was that in the vast
> > majority of cases it would result in a longer record (and one that's
> > more complicated to decode) than a simple list of QTYPEs.
> 
> not only that, but the nsec bitmap is currently uncompressed, which makes 
> large rrtypes pretty dangerous to dnssec's deployment. until that's fixed, 
> noone should be using that bitmap as an example of how to do other things.
> 
> vixie

While it isn't compressed it is windowed.  It's where the type fits
in the window and how many windows that are active that control the
size of the map not whether the type code is large or not.  Yes, using
a generic compression algorithm would probably result in less bits.

11:36:33.535473 IP 127.0.0.1.53 > 127.0.0.1.59788: 64667$ 1/0/0 NSEC (85)
        0x0000:  4500 0071 3553 0000 4011 0000 7f00 0001  E..q5S..@.......
        0x0010:  7f00 0001 0035 e98c 005d fe70 fc9b 81a0  .....5...].p....
        0x0020:  0001 0001 0000 0000 0369 7363 036f 7267  .........isc.org
        0x0030:  0364 6c76 0369 7363 036f 7267 0000 2f00  .dlv.isc.org../.
        0x0040:  01c0 0c00 2f00 0100 000d a500 2407 6973  ..../.......$.is
        0x0050:  632d 736e 7303 6f72 6703 646c 7603 6973  c-sns.org.dlv.is
        0x0060:  6303 6f72 6700 0006 0000 0000 0003 8001  c.org...........
        0x0070:  40                              

isc.org.dlv.isc.org.    3493    IN      NSEC    isc-sns.org.dlv.isc.org. RRSIG 
NSEC DLV

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-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: ma...@isc.org

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