Re: AS SET

Yes this is what the guys explained to me.

Thanks!

On 16 March 2010 11:56, just kennie <justkennie_at_gmail.com> wrote:

> Please correct me if I am wrong......
> Advertising a summary route without the AS info could cause a loop
> because the receiving router might have one of it prefixes summarized,
> so when it looses connection to this prefix, he may be tempted to use
> this summary route which will result in a loop.
>
>
>
> On 3/14/10, Muzammil Malick <malickmuz_at_gmail.com> wrote:
> > Thanks
> >
> > but how could this cause a loop?
> > If the local router has a more specific route to a destination that is
> > covered by the summary then it will use that.
> >
> > R1 ----------- R2
> >
> > If R1 advertises 10.0.0.1/24 to R2 and then R2 advertises back a summary
> for
> > 10.0.0.0/16 without AS info. R2 has now covered many other prefixes
> which
> > may have come
> > from other AS' and even the prefix from R1, however if R1 has more
> specific
> > routes it will use these. If it doesn't have more specific info then this
> > will be its only route anyway so
> > how can a loop be formed?
> >
> >
> >
> > On 14 March 2010 19:21, Nadeem Rafi <nrafia_at_gmail.com> wrote:
> >
> >> If i am wrong please correct me.
> >>
> >> when bgp is summarized then information for the routes being summarized
> is
> >> lost. And summarizing AS is considered to be originator of this new
> route.
> >> All the AS afterwards dont have knowledge of routes being summarized
> that
> >> from which AS they belong. And this can led from non-optimal routing to
> >> routing loops, because of this as-set is used to feed with
> >> more information about routes being summarized.
> >>
> >>
> >>
> >> HTH
> >>
> >> On Sun, Mar 14, 2010 at 10:12 PM, Muzammil Malick
> >> <malickmuz_at_gmail.com>wrote:
> >>
> >>> Hi
> >>>
> >>> Could someone please help me out and explain why you would include AS
> >>> information in a bgp summary (aggregate-address 10.0.0.0 255.255.0.0
> >>> summary-only as-set)
> >>>
> >>> I know what it does and how to use it but why from a design perspective
> >>> would you want to send AS information as apart of a summary.
> >>> Can someone provide an example?
> >>>
> >>>
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>
>
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> Idowu Kehinde
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Received on Tue Mar 16 2010 - 12:51:13 ART