[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [RRG] Precision of the goals?



Sorry, I've been off-line... below...

On 2007-05-10 23:46, Lixia Zhang wrote:

On Apr 30, 2007, at 12:54 PM, Tony Li wrote:
On Apr 30, 2007, at 1:52 AM, Brian E Carpenter wrote:

Thus, the first required goal is to provide significant improvement
   to the scalability of the routing plane.

Should we be looking for a way to measure that goal? For example,
by having a goal that the RIB size goes like log(N) for some measure N?
Obviously that is simplistic - my point is to ask whether we
want to define metrics.

Well, my take on it is that we will have a hard time being quantitative about all of the goals. How do we quantify 'deployability', for example? And if we can't quantify all of the goals, is there really a benefit in quantifying some of them?

I think so, where it's possible. And I'm really not looking for
firm numbers necessarily - just something that allows us to review
a proposed solution other than by gut feeling.

There are also other considerations, such as folks "designing to the test" and gaming the system by rigging the goals that we should avoid, IMHO.

Yes. But things like "log N rather than N^2" probably can't be gamed.

Brian,

I'm not opposed to the suggestion, but I'm not sure how to specify metrics that will capture proper space/time complexity measures without inviting folks to drown us in detail or enable gaming. Specific contributions are most welcome.

Let me try a strawman here: as far as we can see from the BGP data, the number of ISPs has been grown very slowly over the years; today's routing scalability problem is largely due to the growth of Internet user sites which are also multihomed. And because the ISPs are the ones who feel the pain when the routing system size grows beyond "comfortable" range, there seems a feedback loop for ISP-induced routing growth. So What about adding the following quantifier to the existing scalability goal:

   the first required goal is to provide significant improvement
   to the scalability of the routing plane; it is highly desirable
   to make the routing plane scale independently from the Internet
   user population growth.

Yes, I think that is a good compromise between completely qualitative
goals and over-specification; it offers some sort of measuring
stick.

    Brian

--
to unsubscribe send a message to rrg-request@psg.com with the
word 'unsubscribe' in a single line as the message text body.
archive: <http://psg.com/lists/rrg/> & ftp://psg.com/pub/lists/rrg