Hi folks, Sunday (15 March 1998)
Extracted below (with line numbers) is summary information from the five
SNMPv3 documents (RFC 2271 to RFC 2275, January 1998).
As Randy Turner has argued, it IS possible to use a small subset (Target
and Notification MIBs in RFC 2273) of the SNMPv3 MIB modules (there are
a total of 7 SNMPv3 MIB modules) to achieve a simple (security-free)
SNMP trap registration mechanism (see the 'snmpNotifyBasicCompliance'
declaration at line 2773 of RFC 2273).
But, the functionality provided is INFERIOR in important ways to that
provided by the JAM (Job Async Monitor) MIB that Joe Filion and I posted
on Wednesday (4 March 1998) or to my informal understanding of the IBM
method presented by Harry Lewis during last week's PWG monthly meeting
in Austin, TX.
1) The JAM MIB and Historic SNMP Party MIB (RFC 1447) support scope
(traps of 'interest') specified as object identifier subtrees.
The SNMPv3 Target/Notification MIBs support scope only by short (32
character) UTF-8 tags, which are NOT standardized by SNMPv3 and (due
to their length) are NOT amenable to standardization.
2) The JAM MIB supports automatic trap deregistration specified as
'DateAndTime'.
The SNMPv3 Target/Notification MIBs do NOT support automatic trap
deregistration at all!
3) The JAM MIB supports simple integer indices for all 'read-create'
object groups (written by a remote client).
The SNMPv3 Target/Notification MIBs support indices ONLY as (32
character) UTF-8 'SnmpAdminString' values, seriously restricting the
number of SNMP objects which can be transferred in a single packet.
Since SNMP runs over UDP (in the Internet suite) and there is no
'chunking' for SNMP requests, this limitation is significant!
4) The JAM MIB supports a 'read-only' lookup table (maintained by the
SNMP agent on the device) which provides direct lookup from SNMP
transport domain and transport address to a client (target) trap
registration entry (to avoid duplicate registrations).
But, the SNMPv3 Target/Notification MIBs support only brute force
(ie, read the entire Target table) for this important functionality!
5) The JAM MIB scales well to a very large number of (end-user) trap
client (target) registrations.
But, the SNMPv3 Target/Notification MIBs do not scale well. They
are intended ONLY for use by network management stations!
6) Randy has suggested that SNMPv2/SNMPv3 'Inform' requests/responses
could be used for (questionably) 'reliable' event notification.
But, 'Inform' is intended by the SNMPv3 developers to be used ONLY
for reporting up a hierarchy of network management stations!
Also, 'Inform' is not defined in SNMPv1, so the huge installed base
of SNMP agents which (almost exclusively) speak SNMPv1 cannot use
'Inform'.
7) Lastly, as SNMP agent toolkits become available from software tool
vendors, any 'local' use of SNMPv3 Target/Notification MIBs by the
printer industry vendors will inevitably conflict with the very
different intent of the SNMPv3 developers. Recall why the Job Mon
MIB is a PWG standard and NOT an IETF standard!
As I hope most of you know, I'm dedicated to the use of standards where
available and applicable. But the SNMPv3 MIBs were never intended to be
used by many clients. They simply aren't appropriate to the problem of
trap registration for PWG Job Mon MIB and IETF/PWG Printer MIB traps.
Cheers,
- Ira McDonald (High North, outside consultant at Xerox)
------------------------------------------------------------------------
**** SNMPv3 Documents ****
rfc2271.txt: Architecture for Describing SNMP Management Frameworks
- 38-44:
This document describes an architecture for describing SNMP
Management Frameworks. The architecture is designed to be modular to
allow the evolution of the SNMP protocol standards over time. The
major portions of the architecture are an SNMP engine containing a
Message Processing Subsystem, a Security Subsystem and an Access
Control Subsystem, and possibly multiple SNMP applications which
provide specific functional processing of management data.
- 1913:
SNMP-FRAMEWORK-MIB DEFINITIONS ::= BEGIN
- 2420:
snmpFrameworkMIBCompliance MODULE-COMPLIANCE
rfc2272.txt: Message Processing and Dispatching for SNMP
- 41-46:
This document describes the Message Processing and Dispatching for
SNMP messages within the SNMP architecture [RFC2271]. It defines the
procedures for dispatching potentially multiple versions of SNMP
messages to the proper SNMP Message Processing Models, and for
dispatching PDUs to SNMP applications. This document also describes
one Message Processing Model - the SNMPv3 Message Processing Model.
- 810:
SNMP-MPD-MIB DEFINITIONS ::= BEGIN
- 936:
snmpMPDCompliance MODULE-COMPLIANCE
- 976:
SNMPv3MessageSyntax DEFINITIONS IMPLICIT TAGS ::= BEGIN
rfc2273.txt: SNMPv3 Applications
- 37-44:
This memo describes five types of SNMP applications which make use of
an SNMP engine as described in [RFC2271]. The types of application
described are Command Generators, Command Responders, Notification
Originators, Notification Receivers, and Proxy Forwarders.
This memo also defines MIB modules for specifying targets of
management operations, for notification filtering, and for proxy
forwarding.
- 1561:
SNMP-TARGET-MIB DEFINITIONS ::= BEGIN
- 2209:
snmpTargetCommandResponderCompliance MODULE-COMPLIANCE
- 2305:
SNMP-NOTIFICATION-MIB DEFINITIONS ::= BEGIN
- 2773:
snmpNotifyBasicCompliance MODULE-COMPLIANCE
- 2881:
snmpNotifyBasicFiltersCompliance MODULE-COMPLIANCE
- 2894:
snmpNotifyFullCompliance MODULE-COMPLIANCE
- 2960:
SNMP-PROXY-MIB DEFINITIONS ::= BEGIN
- 3242:
snmpProxyCompliance MODULE-COMPLIANCE
rfc2274.txt: User-based Security Model (USM) for SNMPv3
- 37-41:
This document describes the User-based Security Model (USM) for SNMP
version 3 for use in the SNMP architecture [RFC2271]. It defines the
Elements of Procedure for providing SNMP message level security.
This document also includes a MIB for remotely monitoring/managing
the configuration parameters for this Security Model.
- 861:
USMSecurityParametersSyntax DEFINITIONS IMPLICIT TAGS ::= BEGIN
- 1701:
SNMP-USER-BASED-SM-MIB DEFINITIONS ::= BEGIN
- 2439:
usmMIBCompliance MODULE-COMPLIANCE
rfc2275.txt: View-based Access Control Model (VACM) for SNMPv3
- 38-42:
This document describes the View-based Access Control Model for use
in the SNMP architecture [RFC2271]. It defines the Elements of
Procedure for controlling access to management information. This
document also includes a MIB for remotely managing the configuration
parameters for the View-based Access Control Model.
- 541:
SNMP-VIEW-BASED-ACM-MIB DEFINITIONS ::= BEGIN
- 1356:
vacmMIBCompliance MODULE-COMPLIANCE
------------------------------------------------------------------------