BGP announcements and small providers

Dear all,

  I'm writting to this list because I think this is a good forum for
this question, as my questions relates to the amount of
routing announcements that are sent to all Internet, and actually I'm a
beginner on these points.
  But first let me introduce myself: I'm currently working for
Telefonica, at Spain, giving internet access to spanish ISP's. We've got
many customers here, and so the numbers of networks being announced by our
AS is currently quite big, but this number is getting bigger and bigger as
we are experiencing an exponential growing of the Internet market at Spain
(due also to a special service called "Infovia" specially designed here to
make Internet access through normal telephone lines much easier for final
users). As you will likely imagine, I'm currently in charge of routing
issuess at our network (which is called Ibernet).
  As part of this routing issues, I'm in charge of the BGP
configuration, and always following CIDR rules for peerings. Up to now, we
used to have, apart from the peering with our providers, BGP peering with
a couple of customers; but these customers where big enough, and they were
announcing several /17, /18 and /19.
  But now we are receiving many petitions from much smaller ISP's
asking for BGP connections. These small customers are going to announce
few networks (a couple of /24, or some /23). We have no problems to
configure our routers with more BGP peerings, as our routers can support
it, but I'm a little bit concerned about the impact of such small
announcements to the whole Internet.
  I know there are some controversials about network announcements
flapping on the Internet, and that there is something called "dampening",
whose way of working I don't know, but I guess it is for avoiding
flapping; and I think that people is also worried about the amount of
networks that are being announced through Internet, and indeed that some
providers (Sprint ?) are filtering high prefixes (maybe higher than /19,
or at least they did ?). I don't know if other providers are now, or are
going in the future, to establish such kind of policies, but I'm affraid
that accepting BGP peerings with small provider that are to announce only
/23 or /24 could create problems in the future, first for the own customer
(who could have his announcements suppressed by other AS's) and second, to
the whole Internet if all carriers are doing the same.
  So I would like to know what is the point of view from other
people, with much more experience than us in these points, about accepting
these small BGP peerings. Is it really a problem, or I am worrying about
nothing ? Are there any specific rules (apart, of course, from the CIDR
rules) that the routing administrators of carrier providers, like us,
should follow all over the world in order to make the routing at Internet
much easier, or everyone can do whatever he wants ?

  I would very much appreciate any comments on that (and sorry for
the long of this e-mail :slight_smile:

  Best regards