Subject: [Capwap] The open issues we have in the MIB drafts

From: young <[email-masked]>
Date: Mon, 13 Oct 2008 10:46:22 +0800

Hi, 

Here are open issues we have till now:

1)       The MAX-ACCESS property of MIB objects

Which objects should use write access right?  In the CAPWAP-DOT11-MIB,

We defines some objects with write access right as the IEEE MIBs usually
defines

Some objects with write access right to support configuration operation.

So we think the design of CAPWAP-DOT11-MIB as an 802.11 binding should keep

Consistent with IEEE MIBs.  We think current design of it is OK.

So this question is mainly for CAPWAP-BASE-MIB. I think it is a common rule
in the IETF MIBs 

To define most objects with read access right, and objects with write access
right are

Rarely defined. 

Considering of configuration operation is an important function of CAPWAP
protocol, so

We should define some objects with write access right? This idea is right?

If it is correct, kindly suggest which object (TLV) should support write
access right?

2) As per the section of  "4.7.  CAPWAP Protocol Timers" and "4.8.  

CAPWAP Protocol Variables" in the base protocol, which timer or Variables is
necessary to 

operator and should be defined in the CAPWAP-BASE-MIB? Whether requires MIB
to cover all of them? 

As SNMP agent is only required in the AC, how about we only cover variables
or timer on the AC?

Any other open issues?

We plan to close all these open issue in the next version released.

Regards

Richard

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From: "David Harrington" <[email-masked]>
Date: Mon, 13 Oct 2008 11:00:56 -0400

Hi,
 
I have not reviewed your latest MIBs (and do not plan to), but I have
some general recommendations in response to your questions.

I would find it much easier to respond to your messages inline if you
used plain text format rather than HTML format.

________________________________

	From: young [mailto:[email-masked]] 
	Sent: Sunday, October 12, 2008 10:46 PM
	To: [email-masked]
	Cc: [email-masked]; [email-masked]
	Subject: [Capwap] The open issues we have in the MIB drafts

	Hi, 

	Which objects should use write access right?   

	 In the CAPWAP-DOT11-MIB,

	We defines some objects with write access right as the IEEE
MIBs usually defines

	Some objects with write access right to support configuration
operation.

	So we think the design of CAPWAP-DOT11-MIB as an 802.11
binding should keep

	Consistent with IEEE MIBs.  We think current design of it is
OK.

dbh> Some vendors support write-access in their agents. It therefore
makes sense to define as read-write any object that could be
effectively used to configure the CAPWAP environment. Put another way,
if it makes sense for an object to be writable in an environment where
SNMP SETs are supported, then make the object read-write so the
operators in that environment can write to the objects. If you make
the objects read-only, then, even if the agent supports SNMP SETs, the
operators will not be able to write to them, which would be a bad
thing for those operators.

You can define multiple groups for conformance - such as 
1) one group for read-only objects, which can be used to monitor a
system, 2) a second conformance group for read-write objects, which
can be used to actively configure a system, and 
3) a third group providing read-only support for the read-write
objects; these could be used to monitor the configuration, but not
modify the configuration. 
There are many recent standard MIB modules that allow read-only mode
for read-write objects; check some recent RFCs that contain MIB
modules.	 

	So this question is mainly for CAPWAP-BASE-MIB. I think it is
a common rule in the IETF MIBs 

	To define most objects with read access right, and objects
with write access right are

	Rarely defined. 

	Considering of configuration operation is an important
function of CAPWAP protocol, so

	We should define some objects with write access right? This
idea is right?

	If it is correct, kindly suggest which object (TLV) should
support write access right?

	2) As per the section of  "4.7.  CAPWAP Protocol Timers" and
"4.8.  

	CAPWAP Protocol Variables" in the base protocol, which timer
or Variables is necessary to 

	operator and should be defined in the CAPWAP-BASE-MIB? Whether
requires MIB to cover all of them? 

	As SNMP agent is only required in the AC, how about we only
cover variables or timer on the AC?

dbh> The AC is only one end of the relationship. It is often the case
when trying to determine fauilts or performance, that comparing the
counters from the two sides of the relationship reveals useful
information. It can be useful to passively monitor how each side is
configured to locate mismatched configurations. When used for active
configuration, it might be necessary to configure both sides of a
relationship before the configuration can work. So you might want to
consider whether it will be important for both sides to collect
information about the relationship, or to configure both sides of the
relationship to make the relation viable.

If it is unlikely that both sides will support an SNMP agent, then you
might want the one side that is likely to have an SNMP agent to
monitor information about the itself **and** other side of the
relationship. It might extract useful information from fields in the
CAPWAP messages, and store the information in a MIB so a manager
application can see what seems to be happening, at least from the
standpoint of the single agent. 

(You can compare this to me working with you and an engineer that only
speaks Chinese; since I don't speak Chinese, and the Chinese engineer
does not speak English, it would be helpful if you, who understands
both languages, could write the weekly status report telling me what
he is doing ;-)

	Any other open issues?

	We plan to close all these open issue in the next version
released.

	Regards

	Richard

---

From: young <[email-masked]>
Date: Tue, 14 Oct 2008 09:37:57 +0800

Dear David:

I got your point, and these general suggestions are very helpful. Sometime,
we worry about whether we do design in a correct direction. With it, we will
figure out the access right of objects and consider How to define objects
for timer and variable.

Thanks a lot
Regards
Richard

-----邮件原件-----
发件人: David Harrington [mailto:[email-masked]] 
发送时间: 2008年10月13日 23:01
收件人: 'young'; [email-masked]
抄送: [email-masked]; [email-masked]
主题: RE: [Capwap] The open issues we have in the MIB drafts

Hi,

	Hi, 

	 In the CAPWAP-DOT11-MIB,

	Rarely defined. 

	Any other open issues?

	 

	Regards

	Richard