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

From: Armin Mirsepassi <amirsepassi_at_ccgrp.com>
Date: Mon, 16 Aug 2010 19:08:13 -0400

Jorge,

15.x Quick read faq:
http://www.cisco.com/en/US/prod/collateral/iosswrel/ps8802/ps10587/ps10591/p
s10621/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

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

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Received on Mon Aug 16 2010 - 19:08:13 ART

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