Hi Shane,

I always found this presentation very instructive to educate on the practice 
you are describing: 
http://www.nanog.org/meetings/nanog45/abstracts.php?pt=MTIwMCZuYW5vZzQ1&nm=nanog45

I agree that this is common practice, particularly between content operators.

Roque

On Oct 24, 2012, at 12:03 AM, Shane Amante wrote:

> Danny,
> 
> On Oct 23, 2012, at 3:25 PM, Danny McPherson <[email protected]> wrote:
>> On Oct 23, 2012, at 5:05 PM, John G. Scudder wrote:
>>> BGPSec protecting Origin would stomp on current operational practice, so it 
>>> would need to be justified more strongly than "seemed like a good idea at 
>>> the time".
>> 
>> What does this mean?  What operational practice?  
> 
> I suspect John is referring to the operational practice employed by some 
> networks, right now, whereby they overwrite ORIGIN during receipt of an 
> UPDATE into their network to 'normalize' ORIGIN to a consistent value.  This 
> is especially valuable in cases where one network, A, is multi-homed to an 
> adjacent network, B, and network A may not be announcing a consistent set of 
> BGP path attributes associated with a set of IP prefixes at all locations.  
> Ultimately, this practice allows network B to consistently skip over ORIGIN 
> and, instead, evaluate more well-understood BGP Path Selection criteria like 
> MED's, IGP metric, etc. across the full set of "common" BGP routes, (i.e.: 
> those with the same AS_PATH, LOCAL_PREF, etc.), learned across all exit 
> points to network B.
> 
> Oh, and FWIW, I agree with the sentiment that "securing" BGP ORIGIN in BGPSEC 
> is a bad idea, for the very reason that I've stated above and others have 
> provided on the list.  
> 
> -shane
> 
> P.S. -- I would like to coin the saying: "The difference between theory and 
> practice in BGP is, in practice, BGP works in today's Internet, because it's 
> not confined by any theory." :-)
> 
> 
> 
>> -danny
>> 
>> 
>> 
>> 
>> 
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