Re: Was multicast routing behavior changed in new 15.0T code?

Hi Carlos,

Thanks a lot for pointing out that link. I guess I should've looked closer
at the documentation. Maybe I am missing something from that reading or need
to do some more research but I still don't understand why I had to disable
MFIB in order to get the group to RP mappings. It is clear now that the
tunnel came up because the router learned the RP mappings, but in order to
make it learn those RP mappings I first had to disable MFIB. I don't know if
this is because of the fact that I was connecting to 3560s and one of those
3560s is the RP. I hope that is not the reason, that would really suck. I
will try to do some more testing maybe during the weekend and see how it
goes. Thanks again.

Joe,

Unfortunately I am not using any rack vendor. These are internal racks we
have at our disposal for study purposes (physical topology is INE topology)
and all those racks were upgraded to 15.0 like two weeks ago. This issue
popped up while I was practicing and it was brought to my attention. Sorry I
cannot help you.

Regards,
Jorge

On Wed, Aug 18, 2010 at 11:25 AM, Carlos G Mendioroz <tron_at_huapi.ba.ar>wrote:

> Answering myself, FTR:
>
>
> http://www.ciscosystems.com/en/US/docs/ios/ipmulti/configuration/guide/imc_mfib_overview_ps10591_TSD_Products_Configuration_Guide_Chapter.html
>
> describes the new "IPv4 enabled CEF mcast forwarding", and the MFIB.
> It introduces the PIM tunnel interfaces used for SM registration.
>
> BTW, I used to think that CEF was linked to "push" control as opposed to
> "pull" (aka on demand) control. Well, mcast CEF is on demand, so I would
> have called it fast switching.
>
> -Carlos
>
> Carlos G Mendioroz @ 18/8/2010 12:15 -0300 dixit:
>
> Jorge,
>> have you received any info on this ?
>> CEF forwarding for mcast seems a new feature of 15, and it would be
>> nice to have a piece of documentation describing it.
>> I see that CEF can be disabled on *output* to an interface... strange.
>> Please post your findings !
>>
>> -Carlos
>>
>> Jorge Cortes @ 16/8/2010 23:57 -0300 dixit:
>>
>>> Hi Armin,
>>>
>>> Thanks for taking the time for looking and responding to this query. The
>>> racks I use for studying were upgraded to 15.0 code two weeks ago. Those
>>> have the full license set, I'm sure of it.
>>> My question however is more focused on the actual behavior, which looks
>>> like
>>> it has been changed. It looks like you have to disable Multicast CEF for
>>> the
>>> routers to learn the RP mappings, and also a tunnel interface is now
>>> created. At least this is what I observed while going thru this exercise,
>>> but I am just curious to know if anybody has tried this and what are the
>>> outcomes.
>>>
>>> Thanks,
>>> Jorge
>>>
>>> On Mon, Aug 16, 2010 at 6:08 PM, Armin Mirsepassi <amirsepassi_at_ccgrp.com
>>> >wrote:
>>>
>>> Jorge,
>>>>
>>>> 15.x Quick read faq:
>>>>
>>>>
>>>> http://www.cisco.com/en/US/prod/collateral/iosswrel/ps8802/ps10587/ps10591/p
>>>> s10621/qa_c67_561940.html<
>>>> http://www.cisco.com/en/US/prod/collateral/iosswrel/ps8802/ps10587/ps10591/p%0As10621/qa_c67_561940.html>
>>>>
>>>>
>>>> I havnt bought or used 15.x with ISR Gen 1, I will take a risk and
>>>> assume
>>>> it's the same as with Gen 2, unless im missing something. Look at
>>>> pictures
>>>> in below ordering doc for a little better explanation of the license
>>>> features, pretty much same as above.
>>>>
>>>>
>>>> http://www.cisco.com/en/US/prod/collateral/modules/ps10598/ordering_guide_c0
>>>> 7_557736_ps10537_Products_Data_Sheet.html<
>>>> http://www.cisco.com/en/US/prod/collateral/modules/ps10598/ordering_guide_c0%0A7_557736_ps10537_Products_Data_Sheet.html>
>>>>
>>>>
>>>> Otherwise use the feature navigator tool (http://www.cisco.com/go/fn)
>>>> to
>>>> make sure everything you need is available with the licenses you have
>>>> purchased.
>>>>
>>>> If you're using for studies you can request a temp 60 day license
>>>> (http://www.cisco.com/go/license click temp license link at top of
>>>> page)
>>>>
>>>> Armin
>>>>
>>>> -----Original Message-----
>>>> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
>>>> Jorge Cortes
>>>> Sent: Monday, August 16, 2010 1:06 PM
>>>> To: Cisco certification
>>>> Subject: Was multicast routing behavior changed in new 15.0T code?
>>>>
>>>> Hi GS Gurus.
>>>>
>>>> Just ran into an strange issue with multicast routing where the router
>>>> wasn't getting the RP mapping information. The topology is very simple
>>>> as
>>>> it
>>>> is a daisy chain and no RPF failures:
>>>>
>>>> SW---SW(RP)---SW---R
>>>>
>>>> Router interface configuration
>>>>
>>>> interface FastEthernet0/1
>>>> ip address 61.61.128.193 255.255.255.224
>>>> ip pim sparse-mode
>>>> ip ospf mtu-ignore
>>>> duplex auto
>>>> speed auto
>>>> ipv6 address 2001:61:100::4/64
>>>> ipv6 rip RIPNG enable
>>>> !
>>>>
>>>> R4(config)#do sh ip pim rp map
>>>> PIM Group-to-RP Mappings
>>>>
>>>> R4(config)#
>>>>
>>>> So I turned on "debug ip mpacket" on the router to see what was going
>>>> on,
>>>> and also tried to disable "mroute cache" as follows:
>>>>
>>>> R4(config)#int fa0/1
>>>> R4(config-if)#no ip mroute-ca
>>>> The above command is going to be deprecated. Use MFIB commands instead.
>>>>
>>>> Well, looks like this command is not supported anymore, so lets use the
>>>> new
>>>> MFIB commands.
>>>>
>>>> R4(config-if)#no ip mfib ?
>>>> cef Multicast CEF to/from interface
>>>> forwarding Multicast forwarding to/from interface
>>>>
>>>> Not sure the difference between both, so will disable both. The final
>>>> configuration of the interface looks as follows:
>>>>
>>>> interface FastEthernet0/1
>>>> ip address 61.61.128.193 255.255.255.224
>>>> ip pim sparse-mode
>>>> no ip mfib forwarding input
>>>> no ip mfib forwarding output
>>>> no ip mfib cef input
>>>> no ip mfib cef output
>>>> ip ospf mtu-ignore
>>>> duplex auto
>>>> speed auto
>>>> ipv6 address 2001:61:100::4/64
>>>> ipv6 rip RIPNG enable
>>>> !
>>>>
>>>> And right after I'm done with that configuration -which was suppossed to
>>>> be
>>>> used only for debugging purposes- I get the following message:
>>>>
>>>> R4(config-if)#
>>>> *Aug 15 22:54:16.490: %LINEPROTO-5-UPDOWN: Line protocol on Interface
>>>> Tunnel0, changed state to up
>>>>
>>>> And now the RP mappings appear to be working:
>>>>
>>>> R4(config-if)#do sh ip pim rp map
>>>> PIM Group-to-RP Mappings
>>>>
>>>> Group(s) 239.10.5.0/24
>>>> RP 150.1.9.9 (?), v2v1
>>>> Info source: 150.1.10.10 (?), elected via Auto-RP
>>>> Uptime: 00:01:52, expires: 00:02:05
>>>>
>>>> Not sure what exactly is going on with the new code, but I had never
>>>> seen
>>>> this before. First looks like the behavior is now like in IPv6
>>>> multicast,
>>>> where a tunnel interface is created, but I don't understand why it was
>>>> necessary to turn off MFIB for it to work.
>>>>
>>>> Is anybody aware of this behavior? I couldn't find it documented.
>>>>
>>>> R4(config-if)#do sh ver
>>>> Cisco IOS Software, 2800 Software (C2800NM-ADVIPSERVICESK9-M), Version
>>>> 15.0(1)M2, RELEASE SOFTWARE (fc2)
>>>>
>>>> Thanks,
>>>>
>>>> Jorge
>>>>
>>>>
>>>> Blogs and organic groups at http://www.ccie.net
>>>>
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>>>
>>>
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>>>
>>>
>>>
>>>
>>>
>>>
>>
> --
> Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina

Blogs and organic groups at http://www.ccie.net
Received on Wed Aug 18 2010 - 14:49:47 ART