Who, in addition to SprintLink, is currently implementing IP
filtering based on CIDR block size (/19)? And where can I go
to learn more about this issue?
I've read the "Q&A conducted by Christy Hudgins-Bonafield with
Alecia Cooper, group manager SprintLink product management." at
http://techweb.cmp.com/nc/online/sprint.html but couldn't seem
to find much on what other carriers are doing.
Thanks.
Tim Nemec
McLeodUSA
Agis for one that I know of, last I heard Sprint had _stopped_ filtering
blocks smaller than /19 when they fired Doran (I could be wrong).
Who, in addition to SprintLink, is currently implementing IP
filtering based on CIDR block size (/19)? And where can I go
to learn more about this issue?
I beleive AGIS has filters now. You can get the specifics off www.agis.net
and click on Network Engineering and read the Nanog presentation info.
The best place to go is the nanog archives...for more information about
other providers...
AGIS published their route filter criteria:
http://agisgate.agis.net/tsld002.htm
Essentially, they will filter on /19 in the 206+.
They will filter on /24 for the 192-205 range.
Everything else (0-191) will be filtered in the /16.
Lee
Hmm, there is amazing - I understood 2 cases only -
- there is FILTERING in INTERNET,
- there is NOT FILTERING in INTERNET.
It's not big difference for us if there is 1 or 10 big ISP who make
filtering.
But - all you know this filtering have 2 sides. First, it decreases
routing noice in the network. But, 2'th, it prevent address space saving.
It seems (reading your mail) /19 filtering is too raugph for the
INTERNET. It seems it's nessesary to have some filtering to prevent extra
grouth of the routing tables. Ok, why nobody discuss /20 or /21 filtering
_everywhere_?
I must repeat - it's not important for the small ISP and small
enterprises how many ISP over the world produce filtering - it's
important if the filtering exist somewhere or not.
Aleksei Roudnev,
Network Operations Center, Relcom, Moscow
(+7 095) 194-19-95 (Network Operations Center Hot Line),(+7 095) 239-10-10, N 13729 (pager)
(+7 095) 196-72-12 (Support), (+7 095) 194-33-28 (Fax)
Well, that's not quite true. If it's only one or two and they
don't filter their own customers, an ISP can simply get a T1 to everyone
who filters and keep their small blocks working.
David Schwartz
It's amazing - if I'll recomend our small ISP bye 256K link Moscow/USA
(Sprint), guess what they say.
But I am misunderstanded at all - first (in September or earlier) no one
Registry over the world could not allocate for multi-home customer
address space less than /19 (32 networks) and this prevented many
enterprices or institutes from multihome connection to the Internet; just
now (due to your answers) nobody filter our 195.xx or other RIPE's blocks
except to /24 prefix; does it mean customers can get multihome access if
they have /22 or /20 address space?
And why Spring (and AGIS) have changed their filtering policy? Was it my
imagination or they have filtered 195.xx block to /19 prefixes?
Well, that's not quite true. If it's only one or two and they
don't filter their own customers, an ISP can simply get a T1 to everyone
who filters and keep their small blocks working.
If that became a popular plan, it would be an incentive for large
providers to filter as aggressively as they could get away with, to
force more people to buy connectivity. Before long it would no longer
be viable to run a T1 to every such backbone.