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RE: Pitfalls of annoucing /24s

  • From: Forrest
  • Date: Wed Oct 15 17:42:27 2003

This is just one of the many reasons why we need ARIN proposal 2002-3 to 
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:[email protected]]
Sent:	Wednesday, October 15, 2003 4:24 PM
To:	'Phil Rosenthal'; 'John Palmer'
Cc:	[email protected]
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: [email protected] [mailto:[email protected]] On Behalf Of
Phil Rosenthal
Sent: Wednesday, October 15, 2003 4:47 PM
To: John Palmer
Cc: [email protected]
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" <[email protected]>
> To: <[email protected]>
> 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 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.