Re: RIP V1 VLSM

yip I read that wrong

On Wed, Feb 17, 2010 at 8:30 PM, miroslav.kosut
<miroslav.kosut_at_gmail.com> wrote:
> Actually that command will disable validating the update source IP address.
> Not the mask.
>
> If you have a router which is "off" the network, its update is ignored until
> you type "no validate-update-source".
>
> Another thing:
> Suppose you are running a RIPv1 and you have different masks on a link. If
> you receive an update with "host bits" set, it is recognized to be a host
> route then:
>
> R1:fa0/0 --- R2:fa0/0
>
> where
>
> R1:fa0/0 - 10.20.20.1/24
> R1:fa0/1 - 10.10.10.1/24
>
> R2:fa0/0 - 10.20.20.2/16
> R2:fa0/1 - 10.30.30.2/16
>
> Then you will see the following routes on R1 and R2:
>
> R1 will have a 10.30.0.0/24
> R2 will have a 10.10.10.1/32
>
> Lab it, its funny :-))
>
> S pozdravom / Regards,
> Miroslav Kosut
>
> On 17.2.2010, at 16:39, Ruhann <groupstudy_at_ru.co.za> wrote:
>
>> The validation done by RIP when a source interface and destination
>> interface are using different masks can be disabled with
>>
>> # router rip
>> # no validate-update source
>>
>> That will work if R1 and R2 has different masks. Not sure though what
>> the impact would be with the loopback being whatever.
>>
>> --
>> <ruhann>
>> ww.routing-bits.com
>>
>> On Tue, Feb 16, 2010 at 10:17 PM, miroslav.kosut
>> <miroslav.kosut_at_gmail.com> wrote:
>>>
>>> Oh I had a small typo. The update received on /24 is SENT only via /24
>>> interface.
>>>
>>> It behaves the same way as if you were running two separate RIP instances
>>> in
>>> separate VRFs. One VRF includes /16 interfaces and the other one includes
>>> /24 only.
>>>
>>> S pozdravom / Regards,
>>> Miroslav Kosut
>>>
>>> On 16.2.2010, at 19:17, Miroslav Kosut <miroslav.kosut_at_gmail.com> wrote:
>>>
>>>> Hello,
>>>>
>>>> I used to lab one scenario with RIPv1 having four interfaces. All
>>>> belonging to the same classful network of 10.0.0.0/8. Two of them were
>>>> having the mask /16 and the other ones were having /24.
>>>>
>>>> Now the interesting part:
>>>>
>>>> The update I received on /16 interface was sent only through the other
>>>> /16
>>>> interface AND NOT VIA /24 INTERFACES.
>>>> The same is true for /24 interfaces. The update I received on /24
>>>> interface I didn't send out the other /24 interface.
>>>>
>>>> At least subnets of 10.0.0.0/8 have not been forwarded to both /16 and
>>>> /24
>>>> interfaces. I am not sure about different classful networks now.. I
>>>> forgot
>>>> this part, it was even years ago.
>>>>
>>>> Hth
>>>>
>>>> Regards,
>>>> Miro
>>>>
>>>> On Feb 16, 2010, at 7:07 PM, Marko Milivojevic wrote:
>>>>
>>>>> Hello,
>>>>>
>>>>> You guys are missing an important thing here... RIPv1 does not support
>>>>> VLSM, but it DOES support subnetting, as long as masks are of equal
>>>>> length... So, if you have two /24 subnets from major /8 network, they
>>>>> will be sent out. Now, the thing here is... if you use RIPv1, it
>>>>> cannot handle variable masks, because it's ... classless. Try
>>>>> configuring all interfaces on your routers with the same mask and see
>>>>> what happens.
>>>>>
>>>>> --
>>>>> Marko Milivojevic - CCIE #18427
>>>>> Senior Technical Instructor - IPexpert
>>>>>
>>>>> Mailto: markom_at_ipexpert.com
>>>>> Telephone: +1.810.326.1444
>>>>> Fax: +1.810.454.0130
>>>>> R&S Video on Demand Demo: http://bit.ly/aFyrU4
>>>>>
>>>>> On Tue, Feb 16, 2010 at 17:55, Roy Waterman <roy.waterman_at_gmail.com>
>>>>> wrote:
>>>>>>
>>>>>> Actually all disregard my last post :)
>>>>>> Labbed it up exactly and saw this:
>>>>>>
>>>>>> R1#
>>>>>> RIP: sending v1 update to 255.255.255.255 via Serial0/0.12 (10.1.0.1)
>>>>>> RIP: build update entries - suppressing null update
>>>>>> R1#
>>>>>>
>>>>>> R2#
>>>>>> RIP: sending v1 update to 255.255.255.255 via Serial0/0.21 (10.1.0.2)
>>>>>> RIP: build update entries - suppressing null update
>>>>>>
>>>>>> ----------------
>>>>>>
>>>>>> If a /24 mask is used instead of the /16 between R1 & R2, it changes
>>>>>> things:
>>>>>>
>>>>>> RIP: sending v1 update to 255.255.255.255 via Loopback0 (10.2.0.1)
>>>>>> RIP: build update entries
>>>>>> B B B B subnet 10.1.0.0 metric 1
>>>>>> B B B B subnet 10.3.0.0 metric 2
>>>>>>
>>>>>> R1#sh ip ro rip
>>>>>> B B 10.0.0.0/24 is subnetted, 5 subnets
>>>>>> R B B B 10.3.0.0 [120/1] via 10.1.0.2, 00:00:06, Serial0/0.12
>>>>>>
>>>>>>
>>>>>> Gotta love RIPv1.
>>>>>>
>>>>>>
>>>>>> Regards
>>>>>> Roy
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 16 February 2010 17:46, Tony Schaffran (GS)
>>>>>> <groupstudy_at_cconlinelabs.com>wrote:
>>>>>>
>>>>>>> I am not sure. B This is not what I would expect of RIPv1.
>>>>>>>
>>>>>>> Maybe somebody with a more technical answer can chime in.
>>>>>>>
>>>>>>> As this has not been a topic of the CCIE blueprint for some time now
>>>>>>> and I
>>>>>>> have not come across this in an actual network for even longer, I
>>>>>>> just
>>>>>>> do
>>>>>>> not have any more knowledge of it.
>>>>>>>
>>>>>>> Sorry.
>>>>>>>
>>>>>>> Tony Schaffran
>>>>>>> Sr. Network Consultant
>>>>>>> CCIE #11071
>>>>>>> CCNP, CCNA, CCDA,
>>>>>>> NNCDS, NNCSS, CNE, MCSE
>>>>>>>
>>>>>>> CCOnlineLabs
>>>>>>> Your #1 choice for online Cisco rack rentals.
>>>>>>>
>>>>>>>
>>>>>>> From: Sarad [mailto:tosara_at_gmail.com]
>>>>>>> Sent: Tuesday, February 16, 2010 9:42 AM
>>>>>>> To: groupstudy_at_cconlinelabs.com
>>>>>>> Cc: Nadeem Rafi; Cisco certification
>>>>>>> Subject: Re: RIP V1 VLSM
>>>>>>>
>>>>>>> Hi tony,
>>>>>>>
>>>>>>> But as it is a contiguous network it should advertise /16 isnt it? .
>>>>>>> I
>>>>>>> initially thought it should also advertise /24 :(. I am trying to
>>>>>>> catch
>>>>>>> what
>>>>>>> happen with the debug but it doesnt show much pls share if you can
>>>>>>> capture
>>>>>>> anything on debug which shows why it is not advertising.
>>>>>>>
>>>>>>> Sara
>>>>>>> On Tue, Feb 16, 2010 at 11:05 PM, Tony Schaffran (GS)
>>>>>>> <groupstudy_at_cconlinelabs.com> wrote:
>>>>>>> Interesting. B I would not even expect the /16 to be advertised, but
>>>>>>> it
>>>>>>> is
>>>>>>> as
>>>>>>> you describe.
>>>>>>>
>>>>>>> Also as you describe, the /24 definitely does not get advertised.
>>>>>>>
>>>>>>> Tony Schaffran
>>>>>>> Sr. Network Consultant
>>>>>>> CCIE #11071
>>>>>>> CCNP, CCNA, CCDA,
>>>>>>> NNCDS, NNCSS, CNE, MCSE
>>>>>>>
>>>>>>> CCOnlineLabs
>>>>>>> Your #1 choice for online Cisco rack rentals.
>>>>>>>
>>>>>>>
>>>>>>> From: Sarad [mailto:tosara_at_gmail.com]
>>>>>>> Sent: Tuesday, February 16, 2010 9:31 AM
>>>>>>> To: groupstudy_at_cconlinelabs.com
>>>>>>> Cc: Nadeem Rafi; Cisco certification
>>>>>>>
>>>>>>> Subject: Re: RIP V1 VLSM
>>>>>>>
>>>>>>> Yes I have set it up, as per theory of RIP as it is a contiguous
>>>>>>> network
>>>>>>> (10
>>>>>>> range) it should send it. When the loopback is a /16 it sends the
>>>>>>> loopbacks
>>>>>>> but when I change it to /24 it doesnt send it. So is this a
>>>>>>> illustration of
>>>>>>> RIPV1 does not support VLSM ?
>>>>>>>
>>>>>>>
>>>>>>> On Tue, Feb 16, 2010 at 10:39 PM, Tony Schaffran (GS)
>>>>>>> <groupstudy_at_cconlinelabs.com> wrote:
>>>>>>> I do not think RIPv1 will be sending /16
>>>>>>>
>>>>>>> RIPv1 is classless and 10.x.x.x is /8
>>>>>>>
>>>>>>> Have you configured this in a lba to see for yourself?
>>>>>>>
>>>>>>> Tony Schaffran
>>>>>>> Sr. Network Consultant
>>>>>>> CCIE #11071
>>>>>>> CCNP, CCNA, CCDA,
>>>>>>> NNCDS, NNCSS, CNE, MCSE
>>>>>>>
>>>>>>> CCOnlineLabs
>>>>>>> Your #1 choice for online Cisco rack rentals.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf
>>>>>>> Of
>>>>>>> Nadeem Rafi
>>>>>>> Sent: Tuesday, February 16, 2010 8:53 AM
>>>>>>> To: Sarad
>>>>>>> Cc: Cisco certification
>>>>>>> Subject: Re: RIP V1 VLSM
>>>>>>>
>>>>>>> you will not be able to see /24 as rip v1 will be sending /16 major
>>>>>>> network
>>>>>>> only.
>>>>>>>
>>>>>>> HTH
>>>>>>>
>>>>>>> On Tue, Feb 16, 2010 at 7:39 PM, Sarad <tosara_at_gmail.com> wrote:
>>>>>>>
>>>>>>>> Hi Expert,
>>>>>>>>
>>>>>>>> If I have the following scenario, that is two routers connected back
>>>>>>>> to
>>>>>>>> back
>>>>>>>> with a 10 range /16 ip & there are two loopbacks configured on each
>>>>>>>
>>>>>>> router
>>>>>>>>
>>>>>>>> with the same class IPs. If I run RIPV1 on this. Will it advertise
>>>>>>>> my
>>>>>>>> loopbacks to each other.
>>>>>>>>
>>>>>>>> B B B R1
>>>>>>>> R2
>>>>>>>> S0 - 10.1.0.1/16 <---------------------------> S0 -10.1.0.2/16
>>>>>>>> L0 - 10.2.0.1/24 B B B B B B B B B B B B B B B B B
>>>>>>>> B
>>>>>>>> B B L0 -
>>>>>>>
>>>>>>> 10.3.0.1/24
>>>>>>>>
>>>>>>>> Regards
>>>>>>>> Sara
>>>>>>>>
>>>>>>>>
>>>>>>>> Blogs and organic groups at http://www.ccie.net
>>>>>>>>
>>>>>>>>
>>>>>>>>
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>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Regards
>>>>>> Roy
>>>>>>
>>>>>>
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-- 
<ruhann>
www.routing-bits.com
Blogs and organic groups at http://www.ccie.net