Re: Fwd: [ipv6mib] So, where were we?

[Rajiv Raghunarayan <raraghun@cisco.com>]

Hi Margaret,

Margaret Wasserman wrote:
> 
> >  One suggestion
> >     I have heard is to change the MIB indices to integers and
> >     have a mapping table that derives the integer from a more
> >     comprehensive set of variables.  Does this mapping table
> >     exist on the querier or the queried?
> 
> I think that this suggestion involves two tables... One is
> the current forwarding table, but with all of the indexes removed
> and an integer index inserted instead.  The other is an index
> table, with all of the current forwarding table indexes, with
> each set of indexes mapping to an integer.
> 
> I understand why such a table could be useful in cases where
> many different sets of indexes would point to the same
> information...  But, I don't think that's the case here, so
> I don't understand why this would be better.  Can someone
> explain?

IMHO, such a design moves the indexing complexity from the
forwarding table to the associated mapping tables and makes 
the forwarding table simpler. One advantage I see with this
approach is that while all implementations will need to 
implement a simple forwarding table, the complexity of their 
routing modules determines which mapping tables to implement. 
As of now, even a simple routing module would need to (partly)
bear the brunt of a complex forwarding table indexing scheme.
Of course, it would also mean that NMS' would need to query
multiple tables to correlate the route information.

> 
> Another option would be to break the fowarding table up into a
> forwarding table and a next-hop table.  Since there are a
> limited number of next hops, we could have a small number
> of entries in that table and reference them based on an
> integer index in the forwarding table.
> 
> However, I think that any of these sorts of changes should be
> considered as part of an effort to develop a new, more useful
> forwarding table MIB, not as part of the effort to ship a
> minimal version-independent update to the current RFC 2096.

While I agree with you in principle, one thing that bothers
me is the usability of such a mib. If a mib is considered to
be not "completely" usable, and another parallel mib enhancement
work is in progress, what are the chances of someone wanting
to go ahead and implement a partially complete and complex mib 
(unless there is customer pressure of course)??

If users aren't using the existing IPv4 mib due to reasons of 
complexity, incompleteness or performance, what we are doing
may only add to the issues. If we can, in a decent timeframe,
come up with the list of issues (if any) with the existing mib
- we could perhaps see if those issues can be addressed by minor
modifications to the existing mib (though this seems like a minor 
possibility). If so, perhaps we should go that way. Else, work
on a fresh IP forwarding mib could perhaps be started off by the
domain experts, while we could, if deemed useful and necessary 
by then, continue with the minimal modifications that address 
the IPv6 issue.

My 2 cents..

-Rajiv.

> 
> Margaret
bv> 
> --
> !! This message is brought to you via the `ipv6mib' mailing list.
> !! Please do not reply to this message to unsubscribe. To unsubscribe or adjust
> !! your settings, send a mail message to <ipv6mib-request@ibr.cs.tu-bs.de>
> !! or look at https://www.ibr.cs.tu-bs.de/mailman/listinfo/ipv6mib.