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TCP/IP Internet Standard Management Framework and SNMP Versions (SNMPv1, SNMPv2 Variants, SNMPv3)
(Page 3 of 4)
While SNMPsec went away, the idea
of party-based security it introduced never did. It was used as the
basis of the definition of the first full revision of SNMP, when SNMP
Version 2 (SNMPv2) was published in RFCs 1441 through 1452 in April
1993. This new version incorporated the new security model, as well
as making changes to the actual SNMP
protocol operations, changes to the Structure
of Management Information (SMI) standard
(defining version 2 of SMI, SMIv2), and formalizing the concept of the
Internet Standard Management Framework.
Unfortunately, this new standard
too was never universally accepted. Some people thought the whole new
version was a great advance, but others took issue with the party-based
security, claiming it was too complex. I am not familiar with all the
details, but from what I understand, a great deal of debate and discussion
took place over the next couple of years, as an attempt was made to
get everyone on board with the new version.
Acceptance of SNMPv2 never happened.
Instead, different splinter groups broke off and began work
on variants of SNMPv2. To prevent confusion, the original SNMPv2
became known as either SNMPv2 classic (reminiscent of the name
a particular soft drink) or SNMPv2p, with the p
referring to party-based security. Things got very interesting
(and confusing) when the following were proposed and/or developed:
- SNMPv1.5: I can tell immediately that
an idea is probably going to be a problem when it proposes a version
number lower than a number already standardized. SNMPv1.5 was an attempt
to retain the uncontroversial elements in SNMPv2pthe
enhancements to the SNMP protocol and SMIwhile going back to community-based
security as in SNMPv1. It never became a standard itself, but became
the basis of
- Community-Based SNMPv2 (SNMPv2c): This
is SNMPv2p modified to use community strings instead of party-based
security; in essence, the same idea as SNMPv1.5 but with a more official-sounding
name and a few changes. Interestingly, the standard that defines this,
RFC 1901, still has an experimental status, despite the
fact that SNMPv2c actually achieved some degree of commercial success
where the standard SNMPv2p did not.
SNMPv2c was defined by standards RFC 1902 through 1908, which incorporate
other changes including a new version of SMI (SMIv2).
- User-Based SNMPv2 (SNMPv2u): This is an
alternative security method for SNMPv2c, which is based on users rather
than community strings. It is considered simpler than party-based but
more secure than community-string security. It is defined by RFC 1909
and RFC 1910. It too is formally considered experimental.
- SNMPv2*: As if all of the above was not
enough, a well-known vendor decided to define another variant called
SNMPv2* that combined elements of SNMPv2p and SNMPv2u. This was
never formally standardized. (Yes, that's an asterisk in the name. No,
there's no footnote at the bottom of this topic, so dont bother
looking for one. Yes, putting an asterisk in a name is extremely confusing.
No, I don't know how it is that marketing people get paid good money
to come up with names like that. J)
Now, imagine that you were a network
administrator in the mid-1990s and were faced with SNMPv2p, SNMPv2c,
SNMPv2u and SNMPv2*. Which one would you choose? Well, if you are like
most people, you'd choose none of the above, saying I
think I'll stick with SNMPv1 until these version 2 folks get their act
together. And that's basically what happened. Some proponents
of these variations promoted them, but there was never any agreement
and the result was that the success of all of the various and sundry
SNMPv2's was limited. As I said, a classic illustration of how important
universal standardization is.
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Version 3.0 - Version Date: September 20, 2005
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