Re: RIP V1 VLSM

From: Ruhann <groupstudy_at_ru.co.za>
Date: Wed, 17 Feb 2010 17:39:40 +0200

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
>>>>>>
>>>>>>
>>>>>> _______________________________________________________________________
>
>
>>>>>> Subscription information may be found at:
>>>>>> http://www.groupstudy.com/list/CCIELab.html
>>>>>
>>>>>
>>>>> Blogs and organic groups at http://www.ccie.net
>>>>>
>>>>> _______________________________________________________________________
>
>
>>>>> Subscription information may be found at:
>>>>> http://www.groupstudy.com/list/CCIELab.html
>>>>>
>>>>>
>>>>> Blogs and organic groups at http://www.ccie.net
>>>>>
>>>>> _______________________________________________________________________
>
>
>>>>> Subscription information may be found at:
>>>>> http://www.groupstudy.com/list/CCIELab.html
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Regards
>>>> Roy
>>>>
>>>>
>>>> Blogs and organic groups at http://www.ccie.net
>>>>
>>>> _______________________________________________________________________
>
>
>>>> Subscription information may be found at:
>>>> http://www.groupstudy.com/list/CCIELab.html
>>>
>>>
>>> Blogs and organic groups at http://www.ccie.net
>>>
>>> _______________________________________________________________________
>
>
>>> Subscription information may be found at:
>>> http://www.groupstudy.com/list/CCIELab.html
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found
> at:http://www.groupstudy.com/list/CCIELab.html
Blogs and organic groups at http://www.ccie.net
Received on Wed Feb 17 2010 - 17:39:40 ART

This archive was generated by hypermail 2.2.0 : Mon Mar 01 2010 - 06:28:36 ART