Re: BGP conditional adv??

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 1.0.0.0/8 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
>>>>>>>>>> 2.0.0.0/8
>>>>>>>>>> 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:
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>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> 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
>>>>
>>>> _______________________________________________________________________
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>>>> http://www.groupstudy.com/list/CCIELab.html
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>> --
>>> <ruhann>
>>> www.routing-bits.com
>>>
>>>
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>>>
>>
>>
>> --
>> Best Regards,
>>
>> Tolulope.
>>
>
>
>
> --
> <ruhann>
> www.routing-bits.com
>

-- 
Best Regards,
Tolulope.
Blogs and organic groups at http://www.ccie.net