Re: Re- Comments on Chassis Mib
"David L. Arneson" <arneson@ctron.com> Wed, 30 June 1993 20:04 UTC
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To: eah <eah@pau.synnet.com>
Cc: chassismib@cs.utk.edu
Subject: Re: Re- Comments on Chassis Mib
In-Reply-To: Your message of "29 Jun 93 19:09:29 +0800." <9306292305.AA24077@pau.synnet.COM>
Date: Wed, 30 Jun 1993 14:37:49 -0400
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From: "David L. Arneson" <arneson@ctron.com>
> Subject: Time:6:58 PM > OFFICE MEMO Re: Comments on Chassis Mib Date:6/29/93 > This is going to be a rather long comment, so I apologize in advance for >the length. > > I've been going over the current draft, and noticed something that I believe >actually existed before this draft. The text of the draft on page 4 states: > > "A chassis can be thought of as a hierarchical relationship of one or more >"physical locations", each physical location containing one or more physical >modules, and where a physical module, or combinations of physical modules, >might perform one or more network device functions. The relationship between >physical location and physical module can be many to many." > > The actual mib, however, really only supports a one:many mapping for physical >location to physical module. The current chasModuleTable only allows a >reference to one physical location, but many modules may refer to the same >physical location. The question is do we need a many:many mapping between >physical locations and physical modules. I think we do. > > Consider the hypothetical case of a chassis which supports half slot modules >(where two half slot modules may occupy the same slot simultaneously), single >slot modules, and dual slot modules. If we use the current mib to represent a >chassis containing each of these modules, we need two different location types, >a single slot location type (for the half slot and single slot modules), and a >dual slot location type for the dual slot modules. We also need to be able to >determine what "type" a >location is based on what type of module occupies it, rather than being able to >determine it in advance. On the other hand, if the mapping is represented as >many:many, the chassis locations can be described in terms of the more natural, >single slot location type. > > Based on the above, and the comments from Dave Arneson and Mahendra J. Kaycee >regarding the mappings I mentioned in my previous comments, below are some >suggested changes to the current (June 24) draft: > > - Remove chasModuleLocationTypeIndex and chasModuleLocation from the >chasModuleTable into a separate table, and re-instate the unique >chasModuleIndex for each module: > > chasModuleTable > chasModuleIndex > chasModuleType > chasModuleFwVersion > chasModuleHwVersion > chasModuleSerialNumber > chasModuleDescription > chasModuleLastChangeTime > chasModuleAdminStatus > chasModuleOperStatus > > - Add the following table to the chasPhysical group: > > chasModuleToLocationTable > chasModuleToLocationModuleIndex > chasModuleToLocationTypeIndex > chasModuleToLocationLocation > > - Add the following table to the chasEntity group: > > chasEntityToModuleTable > chasEntityToModuleEntity > chasEntityToModuleModule > I have at various times felt that a many to many mapping between modules and slots is useful. As you point out the text implies that we had such an arrangement at one time. > - Change the chasResourceTable definition of chasResourceIndex to refer to a >resource type as opposed to a specific resource, and add a chasResourceCount >object to that table (basically handle this table similarly to the way the >physical location table is handled so that there is one entry per "resource >type"): > > chasResourceTable > chasResourceIndex > chasResourceType > chasResourceCount > Yes providing a list of resource types and the number of each type may be the most useful way of doing this. > - Add the following tables to the chasResource group: > > chasResourceToLocationTable > chasResourceToLocationResourceTypeIndex > chasResourceToLocationResource > chasResourceToLocationLocationTypeIndex > chasResourceToLocationLocation > Do we need to map resources onto physical locations? Isn't the mapping of ModuleToResource and EntityToResource, as specified below, sufficient? > chasModuleToResourceTable > chasModuleToResourceModule > chasModuleToResourceTypeIndex > chasModuleToResourceResource > > chasEntityToResourceTable > chasEntityToResourceEntity > chasEntityToResourceTypeIndex > chasEntityToResourceResource > > - Change the chasPhyConfigTable to include a chasPhyConfigModuleID , and >change the chasPhyConfigResourceID into two objects - >chasPhyConfigResourceTypeIndex, and chasPhyConfigResourceIndex: > > chasPhyConfigTable > chasPhyConfigLocationTypeIndex > chasPhyConfigLocationIndex > chasPhyConfigModuleID > chasPhyConfigResourceTypeIndex > chasPhyConfigResourceIndex > chasPhyConfigEntityID > > - Change the chasLogConfigTable to include a chasLogConfigModuleID, and change >the chasLogConfigResourceID into two objects - chasLogConfigResourceTypeIndex >and chasLogConfigResourceIndex: > > chasLogConfigTable > chasLogConfigEntityID > chasLogConfigResourceTypeIndex > chasLogConfigResourceIndex > chasLogConfigModuleID > chasLogConfigLocationTypeIndex > chasLogConfigLocationIndex > I question if the chasPhyConfigTable and the chasLogConfigTable are required if you have the chasModuleToLocationTable, chasEntityToModuleTable, chasModuleToResourceTable, chasEntityToResourceTable. It seems that we are just presenting the same information in a differnt way. I propose that we use your tables without the chasResourceToLocationTable, chasPhyConfigTable, chasLogConfigTable. This I'm willing to support. > >>>As for the problem with multiple mib views, personally I would prefer to >>>have a "single entry point" to some entity's mib which allowed me >>>to see what views are available for that particular entity. I would >>>much rather see something along those lines, than have every view for >>>every entity included in the chassis mib. >> >>How do you like the MIB view table that I currently have in the draft?> >> >> Ed Heiner >> >>/David Arneson > >I guesss what I was trying to say was rather than having a table of information >about views for each entity, simply provide a single transport domain/transport >address/community combination for V1 implementations that provides access to >the view information for the V1 entity, or a single transport domain/transport >address/dstParty/context combination for V2 implementations that could provide >access to the context and view tables for the particular V2 entity. IMHO, >having a whole table provides little benefit, since the entries don't actually >identify what's available to each view (the management application still has to >query the specific entity to determine what mib subtrees/objects are available >to a given view). > I think we have two differnt things here. The MIB view table that is currently in the draft may supplies perhaps a read-only view, and a read-write view into the MIBs. Yes it may indeed limit your access in other ways. Our proprietary chassis MIB has a mapping between the entities and the MIB groups that are realized on that entity. The idea was that it provided you a place to look to determine which MIBs are supported by a given entity. This I think answers your question. The question I have is that if you have access to that table you then have knowledge of all the MIBs realized by that entity. Suppose on the other hand that I as a network manager do not wish user X to have access to a given section of the MIB. If user X is given access to this table then he would be given knowledge of the existence of these other objects that he is not permitted to see. Is this a potential security leak? > > Ed Heiner > I summary I agree with Ed's requests in location, module, resource, entity mappings, with a few modifications. I also feel that we need to get a better understanding of what we need in MIB views. Does anybody have any additional thoughts? /David Arneson
- Re- Comments on Chassis Mib eah
- Re: Re- Comments on Chassis Mib David L. Arneson
- Re: Re- Comments on Chassis Mib Steve Horowitz
- Re: Re- Comments on Chassis Mib M J Kaycee