From: Peng Zheng (zpnist@xxxxxxxxx)
Date: Thu Aug 29 2002 - 00:22:39 GMT-3
But I think no matter how many ASs and paths, the
smallest MED will be chosen if bgp always-compare-med
enabled. Is it right?
--- Nick Shah <nshah@connect.com.au> wrote:
> Yes, only if using 2 paths, try it with 3 or 4
> paths, 2 recd. from ASX and 2
> recd. from ASY.
>
> Nick
> ----- Original Message -----
> From: "Peng Zheng" <zpnist@yahoo.com>
> To: "Nick Shah" <nshah@connect.com.au>
> Cc: <ccielab@groupstudy.com>
> Sent: Thursday, August 29, 2002 11:51 AM
> Subject: Re: deterministic med
>
>
> > I know that. But it's same as I said. Enable bgp
> > always-compare-med has the same result as enable
> both.
> >
> >
> > --- Nick Shah <nshah@connect.com.au> wrote:
> > > Not sure what you mean here, but.. Consider
> this..
> > >
> > > 192.168.1.0/24 recd. from AS500 MED = 100
> > > 192.168.1.0/24 recd. from AS400 MED = 50
> > >
> > > if BGP deterministic-med is turned on, these
> both
> > > paths will NOT be chosen
> > > based on MED, because they are not from same AS.
> > >
> > > but if BGP always compare MED is turned on, then
> the
> > > path with 50 MED will
> > > be selected.
> > >
> > > rgds
> > > ----- Original Message -----
> > > From: "Peng Zheng" <zpnist@yahoo.com>
> > > To: "Nick Shah" <nshah@connect.com.au>
> > > Sent: Thursday, August 29, 2002 10:42 AM
> > > Subject: Re: deterministic med
> > >
> > >
> > > > But turn on bgp always-compare-med have the
> same
> > > best
> > > > path no matter if turn on bgp deterministic
> med.
> > > Is
> > > > that right?
> > > >
> > > >
> > > >
> > > > --- Nick Shah <nshah@connect.com.au> wrote:
> > > > > Jon
> > > > >
> > > > > I hope you have already read this paper..
> > > > >
> > >
> http://www.cisco.com/warp/customer/459/bgp-med.html
> > > > >
> > > > > regardless of that. I will list down the
> effect
> > > of
> > > > > these 2 commands.
> > > > >
> > > > > * By default (with none of these commands
> > > entered)
> > > > > MED is NOT compared when
> > > > > selecting the best path.
> > > > > * Turning on bgp deterministic-med, turns on
> the
> > > > > feature to compare MED,
> > > > > however it only compares MED, if prefix is
> > > received
> > > > > from same neighbor and
> > > > > the best man wins
> > > > > * Turning on bgp always-compare-med, starts
> > > > > comparing 'same prefix' recd.
> > > > > from 'different neighbors' and the best man
> wins
> > > > > * Turning on both of them may really not be
> > > > > required, but it basically
> > > > > compares if prefixes are recd. in groups of
> AS's
> > > > > (say same prefix from AS
> > > > > 200, via 2 neighbors, and same prefix from
> AS
> > > 100
> > > > > via 1 neighbor).
> > > > >
> > > > > rgds
> > > > > Nick
> > > > > ----- Original Message -----
> > > > > From: "Jon O'Nan" <jononan@columbus.rr.com>
> > > > > To: <ccielab@groupstudy.com>
> > > > > Sent: Thursday, August 29, 2002 8:58 AM
> > > > > Subject: deterministic med
> > > > >
> > > > >
> > > > > > Am I correct that:
> > > > > >
> > > > > > bgp deterministic med - compares med
> within
> > > AS
> > > > > >
> > > > > > VS.
> > > > > >
> > > > > > bgp always-compare-med - compares med from
> > > another
> > > > > AS
> > > > > >
> > > > > >
> > > > > > Thanks
> > > > > > Jon
> > > > > >
> > > > >
> > > >
> > >
> >
>
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