Re: remember the "diameter of the internet"?

["Stephen J. Wilcox" <steve () opaltelecom co uk>]

Path is one of the last things to be checked

BGP first checks all kinds of network admin defined things such as local
prefs etc which ought to be properly set by the admins to ensure traffic
is going the best way (which should include local interconnects rather
than last resort transits). Then all things being well BGP can make
choices on path!

On Tue, 18 Jun 2002, Mathew Lodge wrote:

> At 01:33 PM 6/18/2002 -0400, Pawlukiewicz Jane wrote:
> > Are you asking _why_ there are so many hops between yourself and the guy
> > across town?
>
> He's not, but answer is that BGP's key metric is AS path length. This can 
> have very little to do with the optimality (expressed as efficient use of 
> resources) of the actual packet path.
>
> Cheers,
>
> Mathew
>
>
>
>
> > Jane
> >
> > brett watson wrote:
> > > i sit behind cox-cable service at home, and in troubleshooting why my
> > > connectivity is *so* horrible, i find the following traceroute.  does
> > > anyone do any sane routing anymore?  does diameter matter (we used to talk
> > > about it a long, long while ago).  i guess i'm just old and crusty but this
> > > seems to violate so many natural laws.
> > >
> > > i find in more random testing that i seem to be a minimum of 15 hops from
> > > anything, and it's not just the # of hops, it's the *paths* i travel.
> > > bouncing between two cities several times, on several different provider
> > > networks, from one border to the other.
> > >
> > > wow.
> > >
> > > -b
> > >
> > > traceroute www.caida.org
> > >
> > >     1  10.113.128.1        30  unavailable
> > >     2  68.2.6.25           10  ip68-2-6-25.ph.ph.cox.net
> > >     3  68.2.0.26           40  ip68-2-0-26.ph.ph.cox.net
> > >     4  68.2.0.18           50  ip68-2-0-18.ph.ph.cox.net
> > >     5  68.2.0.10           20  ip68-2-0-10.ph.ph.cox.net
> > >     6  68.2.0.70           10  ip68-2-0-70.ph.ph.cox.net
> > >     7  68.2.14.13          10  chnddsrc02-gew0303.rd.ph.cox.net
> > >     8  68.1.0.168          20  chndbbrc02-pos0101.rd.ph.cox.net
> > >     9  68.1.0.146          30  dllsbbrc01-pos0102.rd.dl.cox.net
> > >    10  12.119.145.125      40  unavailable
> > >    11  12.123.17.54        30  gbr6-p30.dlstx.ip.att.net
> > >    12  12.122.5.86         51  gbr4-p90.dlstx.ip.att.net
> > >    13  12.122.2.114        80  gbr2-p30.kszmo.ip.att.net
> > >    14  12.122.1.93         50  gbr1-p60.kszmo.ip.att.net
> > >    15  12.122.2.42         70  gbr4-p40.sl9mo.ip.att.net
> > >    16  12.122.2.205        60  gbr3-p40.cgcil.ip.att.net
> > >    17  12.123.5.145        60  ggr1-p360.cgcil.ip.att.net
> > >    18  207.88.50.253       90  unavailable
> > >    19  64.220.0.189        80  ge5-3-1.RAR1.Chicago-IL.us.xo.net
> > >    20  65.106.1.86         70  p0-0-0-0.RAR2.Chicago-IL.us.xo.net
> > >    21  65.106.0.34         60  p1-0-0.RAR1.Dallas-TX.us.xo.net
> > >    22  65.106.0.14        120  p6-0-0.RAR2.LA-CA.us.xo.net
> > >    23  64.220.0.99         80  ge1-0.dist1.lax-ca.us.xo.net
> > >    24  206.111.14.238     211  a2-0d2.dist1.sdg-ca.us.xo.net
> > >    25  209.31.222.150      80  unavailable
> > >    26  198.17.46.56       140  pinot.sdsc.edu
> > >    27  192.172.226.123     91  cider.caida.org