Re: BGP conditional adv??

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?
>>>>>>>>>
>>>>>>>>>
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>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> Best Regards,
>>>>>>>>
>>>>>>>> Tolulope.
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Best Regards,
>>>>>>
>>>>>> Tolulope.
>>>>>
>>>>>
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>>>>> Subscription information may be found at:
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>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Best Regards,
>>>>
>>>> Tolulope.
>>>
>>>
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>>
>>
>>
>> --
>> <ruhann>
>> www.routing-bits.com
>>
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>
>
> --
> Best Regards,
>
> Tolulope.
>

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<ruhann>
www.routing-bits.com
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