Chassis MIB comments
kzm@hls.com (Keith McCloghrie) Fri, 21 August 1992 08:44 UTC
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From: kzm@hls.com
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Subject: Chassis MIB comments
To: arneson@yeti.ctron.com
Date: Fri, 21 Aug 1992 01:44:43 -0700
Cc: chassismib@cs.utk.edu
Organization: Hughes LAN Systems
X-Mailer: ELM [version 2.2 PL0]
Hi, My apologies (especially to David) that I've been on vacation, and am just about getting caught up. Here are my comments regarding the mailing-list discussions of the last few weeks. (I also have some other comments on the MIB, based on my own reading of it, after not having looked at it for a while, but I'll put those in another message). Re: chasConfigStatus The wording of the DESCRIPTION was intended to accomodate a card with, for example, one switchable connection to a backplane segment such that if that chasConfigStatus for its connection to one segment was activated, then it automatically de-activates its connection to another segment; thus the wording about the creation of new instances causing the deletion of others. (Note also, that cards may not be switchable or such switching might only be compatible with a subset of the backplane segments; thus the wording about hardware limitations.) As reagrds read-only/read-write. I think they should be read-write, but compliance should allow read-only. We can include text in the DESCRIPTION to reflect this compliance issue (unless and until SMP is adopted :-). Re: chasEntityFunction David's question (to me) to define "concentrator" versus "repeater" was a good question. If somebody can suggest un-ambiguous definitions of these, I'd be happy to have them separated out again. Re: chasEntityParty, and chasEntityCommunity/chasEntityIpAddress These specify the MIB view and the transport address for contacting the agent for this entity. This is not necessarily (one of) that entity's IP addresses (since the agent might be on a different card). In fact, when using SNMP parties, chasEntityIpAddress would not be used. Re: most of chasEntityTable belongs in the systems group of MIB II. There is obviously some confusion here. I'm sure we could do with some additional text in section 5.2 of the Overview discussing this MIB's assumption that there is another MIB view (either in the same or different agent, as indicated by chasEntityParty or chasEntityCommunity/chasEntityIpAddress) which contains the entity's MIB. The Chassis MIB contains only a subset of that entity's MIB stored in this chasEntityTabler. So, yes, most of the chasEntityTable information does come from the system group of MIB-II, but it is the system group of the underlying entity's MIB, not the system group of the Chassis MIB (which would, naturally, contain system-group information about the Chassis itself). In fact, I would argue that chasType is redundant since it is a duplicate of the value of sysObjectId in the same MIB view. In contrast, the chasEntityTable's system-group-like information, while being duplicate values of the underlying MIB view's system-group, is useful to have here specifically because all this information is then contained in the same MIB view (e.g., a single SNMP GetRequest can retrieve, for example all the sysUpTime values of all the entities in the chassis - a powerful feature !!). Anybody got any suggestions about what other frequently accessed MIB objects we could promote and duplicate in the chasEntityTable, and thereby reduce the amount of SNMP traffic needed to manage as chassis ? Re: chasSegmentType taking the same set of values as ifType A nice idea, but unfortunately we all wish ifType had been defined as an OBJECT IDENTIFIER. Making chasSegmentType an INTEGER would be a mistake. Re: chasConfigIfIndex As somebody mentioned, having this would be extremely useful in knowing which entry in the entity's underlying MIB view represents the connection to the backplane segment. There are two problems with it: for some entities, the backplane segment connection will not be an "interface", in particular, repeaters have "ports", not "interfaces". Second, it's not altogether clear to me whether this information would be available to the Chassis's agent. So, while I can envisage a generalization to cover the port/interface issue, I'm still not sure whether it's practical. If somebody can suggest a way to make it practical, I'd very much like to keep it; if not, we need to delete impractical stuff. Re: LEDs/etc. I agree with David that these are not specific to a chassis, and belong in another MIB. The only way I could justify to have them here (e.g., in the chasSlotTable) would be the same reason I used above to justify the system-group-like stuff in the chasEntityTable, BUT they're not even in another MIB (yet), so I think we should at least defer this from the Chassis MIB. Re: chasUpTime The only way I can see this could work is if the chassis has a non-volatile clock which continues to tick even when the chassis's "network management subsystem" (i.e., its agent) is reset. I don't believe we can assume that (note that SNMP Security with its need for clocks which don't run backwards determined it could not be required). Without a non-volatile clock, when the agent resets, it loses track of how long since the last power-up. Is it the inverse case which is of concern, where the agent continues to run even when power is lost to the chassis ?? (Is this inverse case even possible ?) Regarding another comment on chasUpTime, where somebody stated a problem of "2 agents reporting different values of chasSlotLastChange": my model is that there is only one agent in the chassis which implements the Chassis MIB, so there can NOT be "2 agents reporting different values of chasSlotLastChange". Perhaps, this again indicates some confusion and suggests we need text in the Overview to say that only one agent in a chassis implements this MIB. Re: Power Supply MIB This working group is also preparing a Power Supply MIB, but as a separate document. (right, Bob ?) Keith. PS. Are there any other outstanding issues that I should have commented on ?
- Chassis MIB comments Niels Ole Brunsgaard
- Re: Chassis MIB comments arneson
- Re: Chassis MIB comments Kiho Yum
- Chassis MIB comments Keith McCloghrie
- Re: Chassis MIB comments David L. Arneson (arneson@ctron.com)
- Chassis MIB comments Dan Romascanu
- Re: Chassis MIB comments Keith McCloghrie
- Re: Chassis MIB comments Keith McCloghrie
- Re: Chassis MIB comments Dan Romascanu
- Chassis MIB comments David Perkins
- Re: Chassis MIB comments David L. Arneson (arneson@ctron.com)
- Re: Chassis MIB comments Bob Stewart
- Re: Chassis MIB comments Kiho Yum
- Chassis MIB comments Chris Chiotasso
- Re: Chassis MIB comments Manu Kaycee
- Re: Chassis MIB comments Chris Chiotasso
- RE: Chassis MIB comments {3COM/PDD/PeteW}
- Chassis MIB comments Chris Chiotasso
- RE: Chassis MIB comments Manu Kaycee
- Re: Chassis MIB comments David L. Arneson
- Re: Chassis MIB comments David L. Arneson
- Re: Chassis MIB comments Manu Kaycee
- Re: Chassis MIB comments Bob Stewart
- Re: Chassis MIB comments Mahendra J. Kaycee
- Re: Chassis MIB comments Mike MacFaden
- Chassis MIB comments Dan Romascanu
- Re: Chassis MIB comments Joseph Zur