Re: BGP conditional adv??

Guys i know it does work, he is referring to one of my labs, i was joking
with him, because he used patch instead of path.

On Fri, Feb 26, 2010 at 2:25 AM, Tolulope Ogunsina <togunsina_at_gmail.com>wrote:

> Yes, I just did.
> Assume we have R1, R2,R3 and R4 in AS 1, 2,3 and 4 respectively
> R1 -- R4 --- R3
> |
> R2
>
> R1, R2, and R3 advertise 150.1.x.0/24 into bgp where x is the router
> number.
>
> R4 aggregates the routes to 150.1..0.0/16 with as-set attribute.
> By default, none of the routers get the update anymore since their
> individual routes are a part of the summary.
>
> Using advertise map, we want to make R1 and R3 get the summary; so we
> only advertise the attributes of the prefix form R2 with the summary.
> Using as path access-lists and route-maps on R4 we have,
>
> ip as-path access-list 1 permit ^2$
> route-map adv permit 10
> match as-path 1
>
> router bgp 4
> aggregate-address 150.1.0.0 255.255.0.0 as-set summary-only advertise-map
> adv
>
> Now, R1 and R3 get the summary, R2 doesn't because its AS number is
> carried along with the summary
>
> R1(config-router)#do sh ip bg | i 150.1.0.0
> *> 150.1.0.0 192.168.1.4 0 0 4 2 i
>
> R2(config-router)#do sh ip bg | i 150.1.0.0
> R2(config-router)#
>
> HTH,
>
> On 2/26/10, Ruhann <groupstudy_at_ru.co.za> wrote:
> > Have you labbed this?
> >
> > On Fri, Feb 26, 2010 at 10:54 AM, Tolulope Ogunsina <togunsina_at_gmail.com
> >
> > wrote:
> >> Yes, for conditional route advertisement.
> >>
> >> Advertise-maps in conditional advertisement and Route aggregation
> >> (using the aggregate-address command) perform two entirely different
> >> functions.
> >>
> >> In the latter, the advertise map specifies the "Name of the route map
> >> used to select the routes to create AS_SET origin communities."
> >>
> >> On 2/26/10, Ruhann <groupstudy_at_ru.co.za> wrote:
> >>> Conditional Route advertisement is meant to watch a route. I am not so
> >>> sure it will work the way you want, matching a AS-Path filter..
> >>>
> >>> It watches a Prefix in the table (the watch route), and if that prefix
> >>> dissapear it then advertises another prefix (the advertise prefix)
> >>>
> >>> On Thu, Feb 25, 2010 at 5:35 PM, 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 1.0.0.0/8to
> >>>>>>>>> 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 1.0.0.0/8to
> >>>>>>>>>> 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
> >>>>>>>>>> 2.0.0.0/8
> >>>>>>>>>> to
> >>>>>>>>>> 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.
> >>>>
> >>>>
> >>>> Blogs and organic groups at http://www.ccie.net
> >>>>
> >>>>
> _______________________________________________________________________
> >>>> Subscription information may be found at:
> >>>> http://www.groupstudy.com/list/CCIELab.html
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>
> >>>
> >>>
> >>> --
> >>> <ruhann>
> >>> www.routing-bits.com
> >>>
> >>>
> >>> 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.
> >>
> >
> >
> >
> > --
> > <ruhann>
> > www.routing-bits.com
> >
>
>
> --
> 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
>
>
>
>
>
>
>
>

-- 
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