Entity MIB BOF (ENTMIB)
Reported by Bob Stewart/Cisco Systems
The Entity MIB BOF met once at the Stockholm IETF on 17 July. The
meeting was chaired by Keith McCloghrie.
Agenda
o Present requirements
o Discuss requirements
o Present potential solution
o Discuss potential solution
o Discuss future work
Problem Statement
Keith presented a statement of the problem:
o Need for multiple instances of a MIB occurring more often.
o Should use multiple SNMPv2 contexts rather than change MIBs.
o Context represents MIB in a logical entity.
o One agent may support multiple entities or not, difference is not
important.
o Useful to relate to one or more physical entities
Requirements
1. Find entities in one place.
2. Find relationship between physical and logical.
3. Single and multiple agents.
4. SNMPv1 and SNMPv2.
5. Minimalist approach:
o Read only.
o Avoid specific system architectures.
o If cannot agree---leave it out.
Discussion of Requirements
o This is not the subagent problem.
o For SNMPv1 IP address identifies agent and community string
identifies context.
o Cost justified by existence of need.
o Why read-only? We do not understand configuration well enough.
Interface table cannot create entries. Adding entities difficult
and does not reflect reality. Some want to use it to constrain
reality.
Potential Solution and Discussion
Andy Bierman presented a potential solution, and discussion became
interleaved with the presentation:
o Internet-Draft available as draft-bierman-entmib-mib-00.txt.
o Non-goals to include chassis-specific components or to draw
physical pictures.
o IP-centric for SNMPv1. For other transport domains, use SNMPv2.
o Presented from Draft by examples.
o Values for entLogicalType not clear yet.
o Standardized physical class to be added (e.g., repeater, router).
o Dependent on SNMPv2 definition of a context.
o Issues exist regarding relationship of contained, independent
agents to consistency of Entity MIB information.
o Consider reverse mappings for IfMappingTable and AliasMappingTable.
o Why solve problem for Interfaces MIB and not in general? Need
suggestions for generic approach.
o Add objects for more information if generic enough.
o Should ``removable'' go further or go away?
o What is source of MIB information? Hard code? Operator entered?
Too much if latter? Interaction between software modules?
o Want interface for adding entries? No. All we want for now is
visibility without solving the entire problem.
o Why is setting up this working group different from setting up one
for subagent technology? This sets a standard for interaction
between NMS and agent, not among agents or pieces of agents.
o Can we do physical without logical or logical without physical?
Either can degenerate to simplest contents.
o Main requirement is list of logical entities and way to get to
them. MIB does that. Physical part could be removed.
o Where is the line for using different contexts and using arbitrary
integers for indexing? For example, ifTable could be scalars. We
could add repeaterID.
Conclusion
The final consensus of the meeting was to request formation of a working
group. The Area Director appeared positive.