[ris-int] RIS Beacons

Hi Henk and Matthew,

Thanks very much for including me on these emails.  I have also CC'd
Ramesh Govindan and Paul Francis who are also interested in using the
Beacons.

> > > a) They have more peers giving transit than any other AS on the
> > > Internet.
>
> This was discussed internally right from day one of RIS beacon project.
> Good that the research community have confirmed concerns raised back
> then.

Would it be possible to set up the experiment such that the beacon
alternates across the different upstream providers, i.e., at one point
announced by two providers, then withdraw from one, re-announce to another
one, etc? And iterate using another two different providers.

For one of the multi-homed PSG beacons (hosted by Randy Bush), we are
performing this experiment (shown http://www.psg.com/~zmao/beacon5.jpg) to
understand the effect of fail over behavior.  Perhaps something similar to
this can be set up in the RIS beacon project.  This would be very
interesting to study.

> > >
> > >  b) When a prefix is invisible, it is not clear if this is caused by
> > >     an experimental problem or by the prefix being filtered.  The
> > >     anchor prefix does not solve this problem, there should
> > be one anchor
> > >     per beacon.
>
> Yup, our beacons were deemed practically useless in the paper by Mao,
> Bush et al, so it's good that we're finally fixing above.
>
> What about timestamping and sequence numbers in the BGP messages? Was
> this also something that needed to be addressed?

Perhaps a similar scheme to the PSG beacons can be adopted.  Right now,
for PSG beacons we are overloading the Aggregator AS field to denote the
sequence number (each new announcement has a seq number incremented from
the old one), and aggregator IP field to denote the time at which the
message is sent out.  To prevent people from misinterpreting these two
fields, we make sure that the Aggregator AS is in the private AS range
(64512-65535), and the Aggregator IP is also in the private address range
(e.g., 10/8).

Thanks!

--Morley

> Cheers,
> Matthew
>
> > -----Original Message-----
> > From: ris-int-admin at ripe.net [mailto:ris-int-admin at ripe.net]
> > On Behalf Of Shane Kerr
> > Sent: 28 September 2004 12:25
> > To: Henk Uijterwaal (RIPE NCC)
> > Cc: zmao at eecs.umich.edu; ris-int at ripe.net
> > Subject: Re: [ris-int] RIS Beacons
> >
> >
> > Henk Uijterwaal (RIPE NCC) wrote:
> > > All,
> > >
> > > At SIGCOMM 2004, it became clear that the current beacon prefixes
> > > suffer from 2 problems:
> > >
> > >  a) They have more peers giving transit than any other AS on the
> > > Internet.
> > >
> > >  b) When a prefix is invisible, it is not clear if this is caused by
> > >     an experimental problem or by the prefix being filtered.  The
> > >     anchor prefix does not solve this problem, there should
> > be one anchor
> > >     per beacon.
> > >
> > > So, people suggested that for the next period
> > (1/10/2004-30/9/2005),
> > > we make the following changes:
> > >
> > > 1. A new /19 is requested from the RIPE NCC.  This /19 is split into
> > >    /24's.
> > >
> > > 2. Each RRC annouces 2 /24's.  Assuming A.B.Z is the base address
> > >
> > >     A.B.(Z+2*Y).0/24
> > >     A.B.(Z+2*Y+1).0/24
> > >
> > >    For Y=0 to 13 for the (up to 16) RRC's.
> > >
> > >    The first prefix is announced permanently.  The second
> > one is a flapping
> > >    prefix: up at 0 GMT, down at 2 GMT, up at 4 GMT etc.
> > The pattern may
> > >    be changed at a later stage.
> > >
> > > 3. Inside each /24, a pingable address will be established.
> > >
> > > 4. We ask only 2 or 3 peers at each IX to provide transit for these
> > >    prefixes.  (In other words, we do not ask everybody).
> > >
> > > 5. Other experiments that we do are:
> > >
> > >    - An overflow prefix (prefix announced at 1 RRC,
> > flapping at the next).
> > >    - Hitesh's experiment.
> > >
> > > 6. The current 195.80.224.0/20 is returned to the RIPE NCC
> > >
> > >
> > >
> > > Comments?
> >
> > This looks good to me.
> >
> > --
> > Shane Kerr
> > RIPE NCC
> >
>