Re: BGP conditional adv??

Ivan your configuration will not work

On Thu, Feb 25, 2010 at 7:35 AM, Ivan Hrvatska <ivanzghr_at_gmail.com> wrote:

> OK. I think I get it. Correct me if I'm wrong:
>
> if my agg route has {100,300} which are AS numbers of R1 and R3, R1
> and R3 will discard that agg prefix cause they see it's own AS number.
> When I do this, on the R2 which is originator of agg rute:
>
> ip as-patch acl 1 per ^300$
> route-map XXX
> match as-patch 1
> router bgp 200
> agg-add 3.1.0.0 255.255.240.0 summ-only as-set adv-map XXX
>
> I'm actually permitting only ASN 300 in AS_PATH, so R1 will process
> agg route and install it in BGP table cause it doesn't see it's AS
> number. R3 will discard it. Is this correct? Is this the functionality
> of adv-map with aggregation?
>
> Regards
>
> On Thu, Feb 25, 2010 at 2:47 PM, Tolulope Ogunsina <togunsina_at_gmail.com>
> wrote:
> > Hi,
> > The advertise-map in aggregate address command is different from the
> > advertise map in conditional advertisements.
> > In aggregate address, the advertise-map argument is the "Name of the
> > route map used to select the routes to create AS_SET origin
> > communities"
> >
> > With that said, I do NOT fully understand the scenario you're
> > describing. Please shed some more light.
> >
> > On 2/25/10, Ivan Hrvatska <ivanzghr_at_gmail.com> wrote:
> >> Oh, yea. I didn't read carefully :) First bullet will be done by
> >> default. Third bullet will also be done by default. So, the second
> >> bullet is actually going through the task on reverse way. If 1.0.0.0
> >> is DOWN, nothing is going to be advertised, and if it is UP, only
> >> 2.0.0.0 will be advertised. OK. I get it. I was confused by the way
> >> the task is given.
> >>
> >> As I go further through the BGP i have one more issue.
> >> One task:
> >>
> >> R1------R2-------R3
> >>
> >> R3 has couple of specific nets which are aggregated by R2. R1 only
> >> gets aggregate prefix without atomic-agg attribute (summary-only and
> >> as-set is used). The aggregation should be configured such that R1 in
> >> AS 100 is the only AS that recivies agg route. R3 or future peer
> >> neighbors should NOT receive the agg route.
> >> Solution:
> >> ip as-path access-list 1 permit ^300$
> >> route-map TST per 10
> >> match as-path 1
> >> agg 3.1.0.0 255.255.240.0 as-set summ-only adv-map TST
> >>
> >> First, I planned to solve this task with community no-export. R2 sets
> >> that comm to the agg route and send it to R1.
> >> I don't het what this route-map exactly does in this case? as-path acl
> >> matches prefixes originated in AS 300. What else in combination with
> >> agg-add command?
> >>
> >> regards
> >>
> >> On Thu, Feb 25, 2010 at 11:20 AM, Tolulope Ogunsina <
> togunsina_at_gmail.com>
> >> wrote:
> >>> The solution means advertise 2.0.0.0 if (and only if) 1.0.0.0 exists
> >>> which also means if 1.0.0.0 does NOT exist, do NOT advertise 2.0.0.0.
> >>>
> >>> On 2/25/10, Ivan Hrvatska <ivanzghr_at_gmail.com> wrote:
> >>>> Yes, that is true. But shouldn't solution be: if 1.0.0.0/8 is DOWN,
> do
> >>>> NOT advertise 2.0.0.0:
> >>>>
> >>>> in solution in route-map EXIST you are matching 1.0.0.0, which means,
> >>>> if 1.0.0.0 exist in RIB, advertise what you permit in route-map ADV,
> >>>> and in route-map ADV you permit 2.0.0.0. That's what is confusing to
> >>>> me.
> >>>>
> >>>> On Thu, Feb 25, 2010 at 9:32 AM, Tolulope Ogunsina <
> togunsina_at_gmail.com>
> >>>> wrote:
> >>>>> Hi Ivan,
> >>>>> From the question,
> >>>>>
> >>>>> - if both nets 1.0.0.0 and 2.0.0.0 are up, R1 should advertise them
> both
> >>>>> - if 1.0.0.0/8 is DOWN, R1 should not advertise 2.0.0.0/8 to R3
> >>>>> - if 2.0.0.0/8 is DOWN, R1 should only advertise net 1.0.0.0/8 to R3
> >>>>>
> >>>>> network 2.0.0.0/8 is dependent on 1.0.0.0/8. (second requirement).
> >>>>> 1st and third requirements are the default behavior of the BGP
> process.
> >>>>>
> >>>>> Hence the solution only focuses on the second requirement.
> >>>>>
> >>>>> HTH,
> >>>>>
> >>>>> On 2/24/10, Ivan Hrvatska <ivanzghr_at_gmail.com> wrote:
> >>>>>> Hi experts,
> >>>>>>
> >>>>>> I have some difficulties to catch this scenario with BGP conditional
> >>>>>> adv:
> >>>>>>
> >>>>>> R1-----------R2
> >>>>>> |
> >>>>>> |
> >>>>>> R3
> >>>>>>
> >>>>>> R1 has lo0 1.1.1.1/8, R2 has Lo0 2.2.2.2/8 and R3 has also Lo0
> >>>>>> 3.3.3.3/8. All RTs are in same AS and all of them advertise their
> >>>>>> loopbacks.
> >>>>>> Task is next:
> >>>>>> - if both nets 1.0.0.0 and 2.0.0.0 are up, R1 should advertise them
> >>>>>> both
> >>>>>> - if 1.0.0.0/8 is DOWN, R1 should not advertise 2.0.0.0/8 to R3
> >>>>>> - if 2.0.0.0/8 is DOWN, R1 should only advertise net 1.0.0.0/8 to
> R3
> >>>>>>
> >>>>>> Solution on R1:
> >>>>>> acl 1 permit 1.0.0.0 0.255.255.255
> >>>>>> acl 2 permit 2.0.0.0 0.255.255.255
> >>>>>>
> >>>>>> route-map ADV per 10
> >>>>>> match ip add 2
> >>>>>> route-map EXIST per 10
> >>>>>> match ip add 1
> >>>>>>
> >>>>>> router bgp 100
> >>>>>> neighbor R3 adv-map ADV exist-map EXIST
> >>>>>>
> >>>>>> So, from my point of view this task should do next:
> >>>>>> - if 1.0.0.0/8 is UP (2.0.0.0/8 can also be UP) advertise 2.0.0.0/8to
> >>>>>> R3 (task asks you to NOT advertise)
> >>>>>> - if 1.0.0.0/8 is DOWN (2.0.0.0/8 can also be DOWN), do not
> advertise
> >>>>>> anything
> >>>>>>
> >>>>>> This solution is correct, but I don't get the logic?
> >>>>>>
> >>>>>>
> >>>>>> Blogs and organic groups at http://www.ccie.net
> >>>>>>
> >>>>>>
> _______________________________________________________________________
> >>>>>> Subscription information may be found at:
> >>>>>> http://www.groupstudy.com/list/CCIELab.html
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>
> >>>>>
> >>>>> --
> >>>>> Best Regards,
> >>>>>
> >>>>> Tolulope.
> >>>>>
> >>>>
> >>>
> >>>
> >>> --
> >>> Best Regards,
> >>>
> >>> Tolulope.
> >>
> >>
> >> Blogs and organic groups at http://www.ccie.net
> >>
> >> _______________________________________________________________________
> >> Subscription information may be found at:
> >> http://www.groupstudy.com/list/CCIELab.html
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >
> >
> > --
> > Best Regards,
> >
> > Tolulope.
> >
>

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