Re: pim assert

From: Brian Dennis <bdennis_at_ine.com>
Date: Mon, 23 Sep 2013 00:18:10 -0500

You can see from the output of the show ip mroute command on R4 that
there is a mroute used for the 2.2.2.2 source.

-- 
Brian Dennis, CCIEx5 #2210 (R&S/ISP-Dial/Security/SP/Voice)
bdennis_at_ine.com
INE, Inc.
http://www.INE.com
On 09/21/2013 10:02 AM, Abdul wrote:
> Imran,
>
> Like in all things, its all about understanding fundamentals and put the
> whole picture together. I am sending this email from my phone on the road.
> Otherwise I would have send you Cisco docs, and RFC references to back up
> my answer.
>
> You answer lies in what your looking at right in front of you.
>
> Mroutes are more than just for your reverse path bay to the RP. Mroutes are
> simply multicast static routes thst can be used for both RP and sources.
>
> First of all, you don't even have an RP defined for your (*, g).
>
> Second, just look at your  (s, g), it says right infront of you how the
> reverse path is working.
>
> Third. Can you send us the following:
>
> Your static mroutes
> Your rp address,
> RP overide acls (if there are any)
>
> But again you answer lies right infront.
>  On Sep 21, 2013 9:41 AM, "Imran Ali" <immrccie_at_gmail.com> wrote:
>
>> Mroute  is  their  only  to influence RPF checking , Assert  election
>> depends on AD, METRIC , HIGHEST IP
>>
>>
>> On Sat, Sep 21, 2013 at 2:55 PM, Abdul <rslab007_at_gmail.com> wrote:
>>
>>> Imran,
>>> Its not a bug.
>>>
>>> Look at your output again. Particularly R4. You have an mroute on R4 to
>>> that source.
>>>
>>> It has a higher preference than an IGP route of the same prefix length.
>>>  On Sep 21, 2013 5:01 AM, "Imran Ali" <immrccie_at_gmail.com> wrote:
>>>
>>>>  Routers  R1  and  R4  are  contending to become assert winner ..
>>>> multicast
>>>> packets  are coming from 2.2.2.2
>>>>
>>>>
>>>> sr 2.2.2.2
>>>> R4#sr 2.2.2.2
>>>> Routing entry for 2.2.2.0/24
>>>>   Known via "ospf 1", distance* 111,* metric 84, type NSSA extern 1
>>>>
>>>>   Redistributing via eigrp 100
>>>>   Advertised by eigrp 100 metric 1 1 1 1 1
>>>>   Last update from 172.16.241.2 on Serial1/0.1, 00:01:17 ago
>>>>   Routing Descriptor Blocks:
>>>>   * 172.16.241.2, from 172.16.241.2, 00:01:17 ago, via Serial1/0.1
>>>>       Route metric is 84, traffic share count is 1
>>>>
>>>>
>>>> R1#sr 2.2.2.2
>>>> Routing entry for 2.2.2.0/24
>>>>   Known via "ospf 1", distance *110*, metric 84, type NSSA extern 1
>>>>
>>>>   Redistributing via eigrp 100
>>>>   Advertised by eigrp 100 metric 1 1 1 1 1
>>>>   Last update from 172.16.241.2 on Serial1/0.1, 00:01:43 ago
>>>>   Routing Descriptor Blocks:
>>>>   * 172.16.241.2, from 172.16.241.2, 00:01:43 ago, via Serial1/0.1
>>>>       Route metric is 84, traffic share count is 1
>>>>
>>>>
>>>> R1#
>>>> *Mar  1 02:52:23.983: PIM(0): Send v2 Assert on Ethernet0/0 for
>>>> 225.1.1.1,
>>>> source 2.2.2.2, metric [110/84]
>>>> *Mar  1 02:52:23.991: PIM(0): Assert metric to source 2.2.2.2 is [110/84]
>>>> *Mar  1 02:52:23.991: PIM(0): We win, our metric [110/84]
>>>> *Mar  1 02:52:23.995: PIM(0): Schedule to prune Ethernet0/0
>>>> *Mar  1 02:52:23.995: PIM(0): (2.2.2.2/32, 225.1.1.1) oif Ethernet0/0 in
>>>> Forward state
>>>> *Mar  1 02:52:24.167: PIM(0): Received v2 Assert on Ethernet0/0 from
>>>> 172.16.146.4
>>>> *Mar  1 02:52:24.171: PIM(0): Assert metric to source 2.2.2.2 is [0/0]
>>>> *Mar  1 02:52:24.171: PIM(0): We lose, our metric [110/84]
>>>> R1#
>>>> *Mar  1 02:52:24.175: PIM(0): Prune Ethernet0/0/225.1.1.1 from (
>>>> 2.2.2.2/32,
>>>> 225.1.1.1)
>>>>
>>>> HERE  R1  FIRST  CLAIMED  TO BE WINNER  , THEN LATER DECLARED " WE LOOSE
>>>> "
>>>>
>>>>
>>>> R4#
>>>> *Mar  1 02:51:56.647: PIM(0): Send v2 Assert on Ethernet0/0 for
>>>> 225.1.1.1,
>>>> source 2.2.2.2, metric [0/0]
>>>> *Mar  1 02:51:56.651: PIM(0): Assert metric to source 2.2.2.2 is [0/0]
>>>> *Mar  1 02:51:56.655: PIM(0): We win, our metric [0/0]
>>>> *Mar  1 02:51:56.655: PIM(0): Schedule to prune Ethernet0/0
>>>> *Mar  1 02:51:56.655: PIM(0): (2.2.2.2/32, 225.1.1.1) oif Ethernet0/0 in
>>>> Forward state
>>>>
>>>>
>>>>
>>>>
>>>> R4#show ip mroute 225.1.1.1
>>>> IP Multicast Routing Table
>>>> Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C -
>>>> Connected,
>>>>        L - Local, P - Pruned, R - RP-bit set, F - Register flag,
>>>>        T - SPT-bit set, J - Join SPT, M - MSDP created entry,
>>>>        X - Proxy Join Timer Running, A - Candidate for MSDP
>>>> Advertisement,
>>>>        U - URD, I - Received Source Specific Host Report,
>>>>        Z - Multicast Tunnel, z - MDT-data group sender,
>>>>        Y - Joined MDT-data group, y - Sending to MDT-data group
>>>> Outgoing interface flags: H - Hardware switched, A - Assert winner
>>>>  Timers: Uptime/Expires
>>>>  Interface state: Interface, Next-Hop or VCD, State/Mode
>>>>
>>>> (*, 225.1.1.1), 00:39:23/stopped, RP 0.0.0.0, flags: DCL
>>>>   Incoming interface: Null, RPF nbr 0.0.0.0
>>>>   Outgoing interface list:
>>>>     Ethernet0/0, Forward/Dense, 00:34:46/00:00:00
>>>>     Serial1/0.1, Forward/Dense, 00:39:23/00:00:00
>>>>     Loopback444, Forward/Dense, 00:39:23/00:00:00
>>>>
>>>> (2.2.2.2, 225.1.1.1), 00:00:18/00:02:44, flags: LT
>>>>   Incoming interface: Serial1/0.1, RPF nbr 172.16.241.2, Mroute
>>>>   Outgoing interface list:
>>>>     Loopback444, Forward/Dense, 00:00:18/00:00:00
>>>>     Ethernet0/0, Forward/Dense, 00:00:18/00:00:00*, A*
>>>>
>>>>
>>>>
>>>> though  R4  has  higher AD to  source  (111)  then  R1 but  still he is
>>>> winning the election .....what  could  be  the reason ?
>>>>
>>>>
>>>>
>>>> perhaps  i  told my mind that  this  is  a bug in ios  and i moved on...
>>>>
>>>>
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>>>>
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Received on Mon Sep 23 2013 - 00:18:10 ART

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