Re: BGP conditional adv??

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.
Blogs and organic groups at http://www.ccie.net