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Re: DS MIB - please review this list...


>>>>> Fred Baker writes:

Fred> Explain to me why (as in, answer the argument I made, rather
Fred> than simply trying to nullify it) when the reason there are two
Fred> InetAddress objects in an entry for the purpose of describing
Fred> either an IPv4 or an IPv6 header, having two InetAddressType
Fred> objects, and specifically having them located numerically before
Fred> the InetAddresses, produces a benefit?

I think we agree that you can only interpret an InetAddresses value if
you know the corresponding InetAddressType. And I think we also agree
that we have this construction since we the current SMI does not allow
us to express a discriminated unions in a single variable.

You are asking what the benefit is of having the discriminating
InetAddressType object registered directly before the InetAddress
object (the union). The benefit here is that an application can
(whether that is an agent code generator or a generic manager) can
identify the discriminating InetAddressType for a given InetAddress
union automatically.

Now you can look at this from different viewpoints:

(a) I don't care about this because my tools are not going to take
    advantage of it anyway.

(b) I do agree that there are at least some benefits, but I am not
    willing to pay the price of an additional column or index
    component in cases where you have multiple InetAddress objects of
    the same InetAddressType. Perhaps a slightly improved set of rules
    would make me feel happier (e.g. just require that the
    discriminating object is the last InetAddressType registered
    before the InetAddress - which I think would handle the diffserv
    filter case).

(c) I generally dislike to impose rules like these on SMIv2 MIB
    designers that make the implementation of generic tools easier.
    
(d) I don't care at all.

There might be more possible positions. I am sure we will find out.

/js

-- 
Juergen Schoenwaelder      Technical University Braunschweig
<schoenw@ibr.cs.tu-bs.de>  Dept. Operating Systems & Computer Networks
Phone: +49 531 391 3289    Bueltenweg 74/75, 38106 Braunschweig, Germany
Fax:   +49 531 391 5936    <URL:http://www.ibr.cs.tu-bs.de/~schoenw/>