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= What's the difference between SNMPv2 and SNMPv2c? =

= What's the difference between SNMPv2 and SNMPv2c? =

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A full description is probably beyond the scope of this FAQ.

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{{FAQ:General_13}}

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Very briefly, the original protocol and framework was described

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in RFCs 1155-1157, and is now known as SNMPv1.

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Practical experience showed up various problems and deficiencies

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with this, and a number of revised frameworks were developed to try

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and address these problems.  Unfortunately, it proved difficult to

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achieve any sort of agreement - particularly over the administrative

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framework to use.

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There was less disagreement over the proposed changes to the

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protocol operations.  These included:

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* increasing the range of errors that could be reported

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* introducing "exception values"<br>so a single missing value didn't affect the other varbinds in the same request)

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* a new GETBULK operation<br>(a supercharged GETNEXT)

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* new notification PDUs<br>(closer in structure to the other request PDUs)

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Strictly speaking, it's this revised protocol (originally defined

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in RFC 1905, and most recently in RFC 3416) that is "SNMPv2".

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The only framework based on this protocol that saw a significant

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level of use was "Community-based SNMPv2" or "SNMPv2c" (defined in

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RFCs 1901-1908). This retained the same administrative framework

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as SNMPv1 (with all of the accompanying deficiencies), but using

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the new protocol operations.

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More recently, a new administrative framework has been developed,

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building on the various competing SNMPv2 proposals, and using the

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same SNMPv2 protocol operations.  This is SNMPv3, which is defined

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in RFCs 3411-3418.    It addresses some of the deficiencies of the

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community-based versions, including significant improvements to

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the security of SNMP requests (like it finally has some!).

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SNMPv3 is now a full IETF standard protocol.

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Strictly speaking, SNMPv3 just defines a fairly abstract framework,

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based around the idea of "Security Models" and "Access Control Models".

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It's this combination of SNMPv3 plus accompanying models that actually

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provides a working SNMP system.

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However, the only models in common use are the "User-based Security

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Model" (RFC 3414) and the "View-based Access Control Model" (RFC 3415).

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So "SNMPv3" is frequently used to mean the combination of the basic

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SNMPv3 framework with these two particular models.

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This is also sometimes described as "SNMPv3/USM".

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So in brief:

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* SNMPv2c updated the protocol operations but left the administrative framework unchanged.

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* SNMPv3  updated the administrative framework but left the protocol operations unchanged.

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     [[FAQ:General]]

     [[FAQ:General]]

     {{FAQ:General}}

     {{FAQ:General}}

FAQ:General 13 - Revision history

Dts12: Move FAQ text to a template page