On the peering of pTLAs...

[Guardini Ivano]

Hi all,

here in CSELT we have been collecting IPv6 and IP4 reachability
statistics towards all the 6Bone backbone sites since the beginning
of this year.
I think that in order to understand the quality of a connection a single
measurement is not enough but the average over a significative period
of time should be considered.
Therefore I present here the average pkt. loss and RTT over
the last 2 weeks for most of the core sites.

Thinking that a single figure describing the quality of the connection
may be helpful I tryed to define a single quality factor taking
into account both loss and RTT.
The quality factor I have figured out is an estimate of the
probability Q(RTTmax) to get the answer to an ECHO Request 
within RTTmax ms.
The factor depends on the value chosen for RTTmax. Clearly
if we raise RTTmax the weigth given to the RTT value decreases
and if RTTmax -> infinity then Q(RTTmax) -> 1-Loss = Availability.
On the contrary if we decrease RTTmax the weight of the RTT value
increases.

You can see in the following table the values I obtained with
RTTmax=300 ms and RTTmax=400 ms.

Site		av. Loss av. RTT  Q(300)  Q(400)
--------------------------------------------
VIAGENIE	1,68%	   303,75	0,762	  0,866   
CISCO		5,32%	   352,08	0,454	  0,765   
NRL		6,26%    372,06	0,388	  0,715   
CICNET	6,76%    332,75	0,575	  0,766   
ESNET		7,38%	   348,19	0,449	  0,788   
DIGITAL-CA	7,59%	   389,68	0,341	  0,685   
ISI-LAP	8,01%	   371,01	0,170	  0,755   
ANSNET	8,16%    377,74	0,620	  0,758   
BAY		8,78%	   535,40	0,095	  0,292   
NWNET		11,26%   462,08	0,126	  0,633   
WIDE		13,94%   491,97	0,000	  0,026   
UNI-C		15,90%   324,81	0,535	  0,708   
SURFNET	24,84%   320,49	0,474	  0,653   
UUNET-UK	25,16%   383,51	0,183	  0,576   
SWITCH	26,53%   393,26	0,330	  0,583   
SICS		27,38%   293,76	0,524	  0,651   
JOIN		27,97%   381,09	0,139	  0,528   
G6		28,80%   379,04	0,240	  0,533   
IFB		29,61%   865,95	0,010	  0,124   
TELEBIT	34,46%   548,18	0,004	  0,160   

I hope that this information will help to decide on peerings.

    Bye
         Ivano



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Ivano Guardini  CSELT SpA
via G. Reiss Romoli 274  Torino (Italy)
Tel. +39 11 228 5424
Fax. +39 11 228 5069
e-mail: ivano.guardini@cselt.it
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