One comment/question in line below:

Romascanu, Dan (Dan) wrote:

See in-line a few comments from a contributor perspective. Dan

-----Original Message----- From: David Harrington [mailto:ietfdbh <at> comcast.net]

I strongly support the formation of this WG, and think it should be the "only next step" in NETCONF Data Modeling standards development.

Trying to standardize too much at once without enough

implementation

experience is not going to help. The most critical DM need is to figure out how to use the standard NM data definitions we already have.

My intention is to develop a way to access MIB data via XML-based NM protocols, to take advantage of the existing NM data definitions in the MIB. This is a migration strategy to move from a mainly-SNMP-and-MIB management framework to a multi-protocol-and-multi-data-model management framework. I do not think MIB access is enough. A binary data-based approach like the MIB is fine for automated management, but it is not good for operator-interactive management, and it fails to take advantage of advances in computer networking technology like WWW technologies. For operator-interactice NM, I think we need task-based NM interfaces. The CLI is one approach, and standardizing it would probably be helpful, but the engineering departments of vendors are not very cooperative on doing that; it is easier for engineers to use freeform text when developing CLIs and syslog-style reporting than to use standardized content.

I do not believe that a standard CLI is achievable in the IETF. By now we should assume this is not going to happen.

XML-based management leverages lessons learned from the WWW. While document-based rather than command-based, tasks can often be grouped into a document-type interface, such as a web page. With automated translation from XML into HTML (and related technologies), we can work on developing task-based-document NM interfaces. I think we need to spend more time thinking about operator use-cases, not just technical designs of SMIs. I think it would help to start thinking in terms of modular data models similar to MIB modules, not just a <running> config, but we need to develop an SMI that helps to differentiate config and state info, which SMIv2 doesn't do, Maybe all we need to do is recommend that MIB modules have separate subtrees for config and for state, much as we now recommend separate subtrees for objects and notifications.

Maybe, but at this point in time all the base of standard MIB modules is not designed this way. What are we going to do, re-write these MIB modules, or part of them? This does not seem an achievable task.

I have seen a couple of references in the discussion to State and netconf.  Can we be more specific about what we mean by state here.  Configuration state?  When I think of other types of state such as operational state or quality state I think of either read MIB objects or notifications (traps/informs).

The suggestion of using subtrees for functional (e.g., FCAPS) separation has worked well in some cases (we use 0 for notifications right). 

While I would like to see the reuse of existing standards, such as XSD, we need to support programmatic interfaces to allow (incremental) automation of repetitive tasks. That means we need to provide machine-readable "clues" about the meta-nature of management information. Maybe that can be done in XML using attributes, or namespaces, or hierarchical organization. Maybe it will require a new SMI with all the special fields found in SMIv2 - and more. I think one of the big questions we need to address is whether a new SMI should be developed that is an extension/superset of SMIv2, or is distinct from SMIv2. I think that work involves getting operator feedback of how they work, so we can understand whether we should be trying to merge the existing NM protocols, or should keep them (and their data) distinct. I think we should be considering how to componentize existing standards work, so we can reuse some parts, such as secure transport, while keeping other parts distinct.

I somehow like the paradigm - SNMP for performance monitoring and alerts, Netconf for configuration and status retrieval. Could we consider that the current standard MIB modules based would be used for read configuration operations, like declare it as the status branch in each MIB, ignoring the configuration objects and build atop of it what is needed for configuration, even if this means duplication of some objects. Simple or too simplistic?

That work can advance while we work on developing support for one or more XML-based interfaces to SMIv2 data models, as a migratory step toward multi-protocol management.

Nit: The WG acronym is kind of cryptic and I'm not sure what it supposed to mean. Also, the WG name only describes work items (A) and (B). Security requirements for multi-protocol

access to MIB

data is definitely not covered by the title, and (D) is 'possibly' NETCONF protocol-specific. (?? XSMI ?? SMIX ?? SMINET ??)

I deliberately avoided the use of SMI. As somebody pointed out (you?), this work (A and B) is not developing a new SMI, it is merely translating elements of SMIv2 from one language to another.

Milestones: Any idea how long you think it will take to do

all this

work? Work items: (A)(B) The XSD for SMIv2 data types and TCs draft has been reviewed and refined over a couple years, and it is very much needed, and ready, for standardization.

Yan will be publishing a base datatype translation document, based on libsmi translations. Since this has been defined and used(?) fo ryears, I expect this should be fast - in IETF terms, we can probably finish in seven or eight years . Seriously, I hope this can be done in six months or so, if there is enough interest to work on it. That will be supplemented by the (romascanu) TC translations document. We need to decide whether XSD can express the restrictions adequately to support machine-validation, and whether the amount of machine-validation supported justifies having an XSD for the TC. Having TC translations might be helpful for netconf to go read existng MIB data, without having to also parse SMIv2 MIB documents to understand what the values mean. I think the bigger benefit is defining TCs that can be used by multiple protocols to support consistent semantics across protocols, and XML is the preferred language for most new protocols. This will require case-by-case analysis, and might take time to reach consensus. Of course, not every contentious TC must be included in this document, so if we cut out the contentious ones, this should be able to be wrapped up within a year, I hope.

I would try to push for a more aggressive schedule, even if it's a smaller set of TCs. It's not that all needs to be standardized in RFC form, but it is better to have this in a stable format for other work to re-use it including proprietary implementations to deploy this.

(C) This work item is a bit vague. I'm not sure if it means a mapping between an SNMP EngineID to a NETCONF session identity, or

something

to do with VACM, or something else undefined. I think it is a smart idea to understand all the security issues associated with (D).

I'm looking at the bigger picture of multi-protocol management. There are lots of protocols being developed, both inside and outside IETF, to perform management functionality. As Bob Natale pointed out, the MIB is the "crown jewel" of IETF Management (I think SNMP is as well, when used for what it is good at). I think lots of WGs and lots of other SDOs are going to look at the MIB and say "gee, we should leverage that!" I think we need to set some guidelines about how protocols should deal with the MIB, so that it is not ruined by unconstrained access by multiple protocols, especially write access. But even read-access can be problematic. Security is a process, not a product. The IETF needs to decide how to "balance" security in an environment of multi-protocol management. It makes no sense to protect your house with a front door that has multiple deadbolt locks, if your back door has no locks. It makes no sense to expect operators to go to the trouble of configuring VACM to protect the data in the MIB when using SNMP, if the operator's VACM configuration will just be ignored by netconf and other protocols accessing the MIB. I think we need some guidelines that provide for a more consistent approach to multi-protocol MIB access, than VACM-for-SNMP and nothing-for-others. Personally, I would like to see VACM not be mandatory-to-implement for SNMP, if there is no corresponding mandatory-to-implement access control for other protocols. I don't think the operator community is actually ready for standardized cross-protocol access control, and if it isn't balanced across protocols, then we shouldn't require any NM protocol standards to have a mandatory-to-implement access control model.

I confess that this is confuse for me too. I am not sure that I understand what is the deliverable here, or whether the problem can be solved within the context of this working group.

(D) I support a standard algorithmic translation between SMIv2

conceptual

data models and NETCONF configuration databases, which

includes data

organization and standard protocol operation mappings. I think read-only access instead of full access will be easier to achieve, so it should be done first. The use case for

write access is

not as strong, and the multi-protocol access and security

issues are

harder.

I agree that read-only access would probably be sufficient for netconf to gather state information, statistical information, and notifications. I do not see a lot of reason to support write access to the MIB via netconf.

Yes, see the above.

I do not support a generic XSD representation of SMIv2

macros, without

consideration of the specific XML-based protocol being used. The 'embedded' SNMP protocol operations in SMIv2, as well as the explicit SNMP operations discussed in MIB object

DESCRIPTION clauses,

RowPointer, RowStatus, StorageType, etc., all have to be explicitly mapped to

the

specific NETCONF (or whatever) protocol operations and architecture assumptions.

I think these need to be supported to understand the values of certain fields that might be read from the MIB. RowStatus reflects the operational state of the row, and if netconf is accessing the MIB to determine operational state of the thing represented by that row, it is an important piece of information. But if netconf has no write capability to the MIB, it does not need to know how to manipulate the values. StorageType is also state information about a row that might be important for a netconf client to understand; it might be helpful to know that the MIB representation (or the underlying instrumentation) is in ROM. But if it has no write capability, it does not need to know how to manipulate the row within the constraints of StorageType. The MIB is more or less a relational database, where the relations between rows is important information. If netconf reads a row that has a relationship to another row via a RowPointer, netconf better know how to interpret a RowPointer. (It is important to understand that I make no assumptions that a netconf-client will have a direct connection to an SNMP manager that knows how to parse this information from an SMIv2 MIB module document.) I think we need to walk through these TCs on a case-by-case basis to decide whether we need each one for use with netconf, and what XSD restrictions apply.

Agree with David on this one.

David Harrington dharrington <at> huawei.com dbharrington <at> comcast.net ietfdbh <at> comcast.net _______________________________________________ OPS-AREA mailing list OPS-AREA <at> ietf.org https://www1.ietf.org/mailman/listinfo/ops-area

_______________________________________________ OPS-NM mailing list OPS-NM <at> ietf.org https://www1.ietf.org/mailman/listinfo/ops-nm

-- Jon Saperia (cell) 617-201-2655 (Eve.) 978-461-0264

_______________________________________________
OPS-NM mailing list
OPS-NM <at> ietf.org
https://www1.ietf.org/mailman/listinfo/ops-nm