Re: Decoding UDP SNMP packets

[Juergen Schoenwaelder <schoenw () ibr cs tu-bs de>]

> > > > > Allison, Jason (JALLISON) writes:

Jason> Thanks for the response.  If you are versed with snmp_print and
Jason> asn1_parse I would be very interested in discussing online or
Jason> offline how and why things are done the way they are.  ASN.1
Jason> encoding, IMO, seems a bit convoluted and over-done.  The
Jason> history behind SNMP, SMI, and the OSI CMIP effort is very
Jason> interesting.

I think I understand the code - not sure I am versed. To be precise,
you are looking at a BER decoder since ASN.1 allows to have many
encodings. Infact, today you can encode ASN.1 data types into XML. But
back in the 80s, ASN.1/BER was the approach that everybody found cool
and this is what SNMP uses.

Jason> Maybe you could link me to a good SNMP book outside of
Jason> Orielly's, Stevens TCP/IP series and Rose's "The Open Book".

I think Marshall's book is still pretty good. BTW, there are other
open source BER encoder/decoder that may be more modular than the
print-snmp.c decoder used by tcpdump. The print-snmp code is very
compact (and probably also more efficient - but I never measured
this).

Anyway, if you are interested in discussing general SNMP stuff, I
suggest to start a thread on comp.protocols.snmp since I doubt this is
the right place to have such a discussion.

/js

-- 
Juergen Schoenwaelder    <http://www.informatik.uni-osnabrueck.de/schoenw/>


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