Hi, I am new to this list and would like to ask a (maybe stupid) question to
the dicussion:
If we want to write a script to expand the AS MACRO, how can we avoid to go
into a loop if multiple AS-MACROs reference each other ?
Ping Lu
Cable & Wireless USA
Network Tools and Analysis Group
W: 703-292-2359
E: plu(a)cw.net
> -----Original Message-----
> From: Cengiz Alaettinoglu [mailto:cengiz@packetdesign.com]
> Sent: Wednesday, January 10, 2001 12:14 PM
> To: Shane Kerr
> Cc: Wilfried Woeber, UniVie/ACOnet; farrache(a)cc.in2p3.fr;
> db-wg(a)ripe.net; routing-wg(a)ripe.net; Henk.Uijterwaal(a)ripe.net
> Subject: RE: Loop in AS macro
>
>
>
> Shane Kerr (shane(a)ripe.net) on January 10:
> > Gilles, Wilfried, and all,
> >
> > This is not a bug, or even an inconsistency. Consider the following
> > as-macro objects:
> >
> > as-macro: AS-X
> > members: AS-Y, AS123
> >
> > as-macro: AS-Y
> > members: AS-X, AS456, AS789
> >
> > In this case, AS-X and AS-Y both expand to the same aut-num objects:
> > AS123, AS456, and AS789. However, they may have different
> maintainers,
> > contacts, descriptions, and so on. In RPSL, many more
> kinds of loops are
> > possible as well, in as-set, route-set, and filter-set objects.
>
> RPSL defines semantics when loops exist. However, it does not promote
> them, or prohibit additional restrictions by the registry operators
> not to have loops.
>
> >
> > External software that deals with the set objects needs to do loop
> > detection in order to prevent infinite loops. For as-set
> objects (which
> > are as-macro objects in RIPE-181), this is fairly easy:
> keep a list or
> > hash of the AS sets expanded, and don't expand them again.
> For route-set
> > and filter-set objects it is not quite so easy. If you
> need help with
> > these, you can send me and e-mail and I can explain the
> techniques that
> > I've used for these objects.
> >
> > Shane Kerr <shane(a)ripe.net>
> > Database Software Engineer
> > RIPE NCC
> > +31 20 535 4427
> >
> > p.s. This is actually a feature, not an bug. :)
> >
> > p.p.s. It has been argued (by me) that RPSL allows objects that are
> > logically impossible, but the RFC authors don't seem to think so!
> >
> > On Wed, 10 Jan 2001, Wilfried Woeber, UniVie/ACOnet wrote:
> >
> > > Hi Gilles,
> > >
> > > I guess we wouldn't be able to check against those
> accidents at the time
> > > of a DB _update_...
> > >
> > > But checking the RR internal _data_ consistency could
> maybe become part
> > > of the RIS (or similar) project?
> > >
> > > Henk, any comments?
> > >
> > > An interesting aside: I guess similar problems could occur with
> > > RPSL-based RRs?
> > >
> > > -WW
> > >
> _________________________________:____________________________
> _________
> > > Wilfried Woeber : e-mail: Woeber(a)CC.UniVie.ac.at
> > > UniVie Computer Center - ACOnet : Tel: +43 1 4277 - 140 33
> > > Universitaetsstrasse 7 : Fax: +43 1 4277 - 9 140
> > > A-1010 Vienna, Austria, Europe : RIPE-DB: WW144, PGP
> keyID 0xF0ACB369
> > >
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~:~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~
> > >
> > > To: staff(a)ip.tele.dk, peering(a)tli.de, ip-oper(a)tli.de,
> admin-c(a)tli.de
> > > CC: farrache(a)cc.in2p3.fr, db-wg(a)ripe.net, routing-wg(a)ripe.net
> > > Subject: Loop in AS macro
> > > Date: Wed, 10 Jan 2001 10:28:15 +0100
> > > From: Gilles Farrache <farrache(a)cc.in2p3.fr>
> > >
> > > Dear database managers,
> > >
> > > I notice a loop in the followings AS-MACRO, in fact
> AS-TELEDANMARKINTERNATIONAL
> > > is calling AS-TLI which is calling AS-TELEDK which is
> calling AS-TELEDANMARKINTERNATIONAL.
> > > (and all that make that our automatic filter generation
> tool fails)
> > >
> > > Could you correct those macro and will the Ripe database
> management provide any
> > > control on that kind of loop ?
> > >
> > > Gilles
> > >
> > > as-macro: AS-TELEDANMARKINTERNATIONAL
> > > descr: Tele Danmark customers outside Denmark
> > > as-list: AS1902 AS12461
> > > as-list: AS8881 AS-KOMTEL
> > > as-list: AS13194 AS-BITE
> > > as-list: AS6709
> > > as-list: AS8650 AS-TLI
> > > as-list: AS8542
> > > as-list: AS12294 AS-TSUA AS6807 AS8349 AS12788
> AS12837 AS12872 AS13249 AS15386 AS15497 AS15929 AS16007
> > > as-list: AS12546
> > > as-list: AS15389
> > > tech-c: AS5071-RIPE
> > > admin-c: AS5071-RIPE
> > > notify: staff(a)ip.tele.dk
> > > notify: peering(a)tli.de
> > > mnt-by: AS3292-MNT
> > > changed: jesper(a)skriver.dk 20001103
> > > changed: toba(a)tdk.dk 20001117
> > > changed: tee(a)tdk.dk 20001123
> > > changed: jesper(a)skriver.dk 20001228
> > > changed: jesper(a)skriver.dk 20010109
> > > source: RIPE
> > >
> > > as-macro: AS-TLI
> > > descr: Talkline GmbH, Internet Division
> > > descr: List of ASes according to Talkline Internet (AS8650)
> > > descr: and customers
> > > as-list: AS5605
> > > as-list: AS6783
> > > as-list: AS8650
> > > as-list: AS8881
> > > as-list: AS12461
> > > as-list: AS12546
> > > as-list: AS-TELEDK
> > > as-list: AS-GLOBAL
> > > tech-c: TLIP1-RIPE
> > > admin-c: TLIP1-RIPE
> > > notify: peering(a)tli.de
> > > mnt-by: TALKLINE-MNT
> > > changed: thomas(a)tli.de 19990923
> > > changed: thomas(a)tli.de 19991020
> > > changed: thomas(a)tli.de 19991025
> > > changed: thomas(a)tli.de 20001023
> > > changed: thomas(a)tli.de 20001025
> > > source: RIPE
> > >
> > > as-macro: AS-TELEDK
> > > descr: Tele Danmark and Tele Danmark customers
> > > as-list: AS-TELEDANMARKDANISH
> > > as-list: AS-TELEDANMARKINTERNATIONAL
> > > as-list: AS-BELBONEMEMBERS
> > > as-list: AS-GLOBAL
> > > tech-c: AS5071-RIPE
> > > admin-c: AS5071-RIPE
> > > notify: staff(a)ip.tele.dk
> > > notify: peering(a)tli.de
> > > mnt-by: AS3292-MNT
> > > changed: jesper(a)skriver.dk 19990922
> > > changed: jesper(a)skriver.dk 19991019
> > > changed: jesper(a)skriver.dk 19991025
> > > changed: jesper(a)skriver.dk 19991210
> > > changed: toba(a)tdk.dk 20000903
> > > source: RIPE
> > >
> --------------------------------------------------------------
> ------------------
> > >
> >
> >
>
>
> Cengiz
>
> --
> Cengiz Alaettinoglu Packet Design Inc.
>
>
