This is a part of the problem. I realize that large ISPs are probably against micro-assignments so that they can continue to use address space to treat customers as indentured servants. I guess they can skip Chicago and just filter out any micro-assignments that ARIN may one day issue. My biggest gripe on this topic is about ISPs that assign /24's to multi-homed customers, but filter out /24's received from peers. Verio (the example of the day) accepts /24's (that they likely assigned) from customers but filters these out from others. Are they expecting their peers not to filter these /24's or do they really care? I suppose if their peers adopt filtering policies such as theirs, they can just tell their customers "We accept your /24, but the other guy is filtering it out" Michael -----Original Message----- From: Andrew Dul [mailto:andrew.dul@quark.net] Sent: Wednesday, October 15, 2003 11:35 PM To: Forrest; michael@awtechnologies.com Cc: nanog@merit.edu Subject: RE: Pitfalls of annoucing /24s Forrest, Even if ARIN passes this policy that will not make any provider change their filtering policy. It is true that many providers do use the ARIN allocation sizes to create their filtering rules but the two are not inherently linked. Any ASN can choose the filter on what ever rule set they choose. Andrew At 04:38 PM 10/15/2003 -0500, Forrest wrote:
This is just one of the many reasons why we need ARIN proposal 2002-3
be approved. So that small networks that wish to multihome don't have issues with networks filtering out their /24 along with all the other garbage /24's that are announced.
http://www.arin.net/policy/2002_3.html
If you support 2002-3 I urge you to get on the ARIN Public Policy Mailing List (PPML) and voice your opinion.
http://www.arin.net/mailing_lists/index.html
Forrest
-----Original Message----- From: H. Michael Smith, Jr. [SMTP:michael@awtechnologies.com] Sent: Wednesday, October 15, 2003 4:24 PM To: 'Phil Rosenthal'; 'John Palmer' Cc: nanog@merit.edu Subject: RE: Pitfalls of annoucing /24s
What about the /24's that many ISPs (especially tier 2-3) are assigning to multi-homed customers? What about an IX or "critical infrastructure providers" that may be issued a /24 from ARIN (Policy 2001-3)?
Although it may be rare that a large aggregate would become unreachable to a "large" network, doesn't the possibility exist that a customer with a /24 would become unreachable (to some) due to the aggregate dropping out even though the /24 should still be reachable? That scenario may not be very likely, but the question of assymetric routing and one's ability to balance traffic become issues. Assigning a lower preference to /24's would be a lot friendlier than just throwing them away.
If I am way off base, I fully expect to be corrected (with volume). My flame retardant suit is in place.
Michael
-----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of Phil Rosenthal Sent: Wednesday, October 15, 2003 4:47 PM To: John Palmer Cc: nanog@merit.edu Subject: Re: Pitfalls of annoucing /24s
http://info.us.bb.verio.net/routing.html#PeerFilter
That's how Verio does it, and I assume, that's how most people who filter by length do it as well.
--Phil On Oct 15, 2003, at 4:40 PM, John Palmer wrote:
Good question.
You know there are thousands of legacy /24's out there that were allocated by IANA as /24's How can you aggregate them up if all you have is the
/24?
To those who filter out /24's - how is this done - just by the
netmask
size?
----- Original Message ----- From: "Jean-Christophe Smith" <jsmith@vitalstream.com> To: <nanog@merit.edu> Sent: Wednesday, October 15, 2003 15:34 Subject: Pitfalls of annoucing /24s
In current practice would there be serious jeopardy of portions of
the
internet not being able to reach this address space due to bgp filters or other restrictions? What is the smallest acceptable block of IPs
to that
can be announced without adverse or unpredictable results? Verio would most
likely be picking up these routes from us. I don't want to cause a religious debate, but I am interested in what the industry consensus is.
I'm just doing some research, any comments would be appreciated.
Thanks, Jean-Christophe Smith
--Phil Rosenthal ISPrime, Inc.