When Sprint was filtering there was a demonstrable need based on the 64meg
limit that
mainstream routers had for memory at the time. I do not see that there is
any such physical
limitation today and I guarentee that the router vendors (all two of them)
have learned the lesson
of not including enough address lines on the equipment to allow for easy
memory upgrades.
So we should throw away all the 7200s and similar routers today
because they are in the way of growing numbers of long prefixes,
replacing them with new routers manufactured since the time of
the above-mentioned lesson? And when shall we throw away
the 12000s and similar routers (or components thereof) because
they are underpowered in the face of routing-table growth, compared
to well-established alternatives?
Incidentally, the lesson learned was that sheer storage AMOUNT
is only a (perhaps small) part of the problem, compared to the
processing necessary to use that storage in support of dynamic
routing (in terms of CPU and in terms of accesses to that memory).
Sean.
Still using an 8086 for a desktop?
Obsolences does happen....
Sean,
Not at all. Modern 7200-series routers, with newer NPE's and more memory can
easily handle full tables today, and into the future. Therefore, we don't
need to through away 7200s. However, should we all be held hostage to those
unwilling to upgrade their existing routers, and perhaps eventually, upgrade
to new routers?
Routers are, basically, specialized computing devices, with fairly short
lives, compared to things like household appliances, arc welders, or phone
booths. This is reflected in their shorter depreciation schedules.
As the upgrades that extend the life of the routers, in dealing with larger
routing tables, are also the cheapest - i.e. RAM, controlling routing table
size to prevent vast expenditures of money to replace existing routers
simply doesn't hold water.
The Internet did not collapse on the day that 2501s became incapable of
handling a full view of the routing table. There was little gnashing of
teeth or rending of garments when it happened. That is a lesson well
remembered.
- Daniel Golding
So we should throw away all the 7200s and similar routers today
because they are in the way of growing numbers of long prefixes,
replacing them with new routers manufactured since the time of
the above-mentioned lesson?
No. Not at all. But nor should we cry wolf and defend our corporate
policies with
phoney hysteria. If you are filtering to keep your internal routing tables
clean fine, to
get the most out of your older or less than optimum equipment, fine too, but
don't say
the "the internet is in danger of imminent collapse if we don't do this"
either.
And when shall we throw away
the 12000s and similar routers (or components thereof) because
they are underpowered in the face of routing-table growth, compared
to well-established alternatives?
As soon as it becomes pratical. But again, don't defend the (legitimate)
position
of wanting to get the most mileage out of your installed equipment base or
*not* wanting to spend millions of dollars on forklift expansion by saying
that
its for the good of the internet. Although this is certainly the first time
I've seen
ivory tower idealism (aka nice clean routing tables with short allocations)
match
up to the goals of a real world corporation (aka lets encourage customers to
buy
our service and at the same time prolong the life of our core routers by a
year
or so).
Incidentally, the lesson learned was that sheer storage AMOUNT
is only a (perhaps small) part of the problem, compared to the
processing necessary to use that storage in support of dynamic
routing (in terms of CPU and in terms of accesses to that memory).
Historically router CPU technology has lagged behind the server industry, at
least
in raw processing capability. Well, there was the fine machine made by Bay,
but
that proved beyond a shadow of a doubt that faster with more memory does not
a stable router make. But that's a different thread.
-vb
If it happens faster then you amortize the cost of capital then your
investors will go elsewhere. This is not 1999. Money is no longer
cheap. Business plans need to be profitable. Spending millions of dollars
on a new set of core routers on less than a 3 year cycle can lead to
low stock prices, de-listing and possible bankruptcy..
Economic reality does happen ....