Re: Multicast Understanding

to make things crystal clear. add another router to R1 .. so that and ping
from R0 ! in this case the stream will be one,. and there will be a unique
assert winner!

                      / R3----
R0----R1 ===< |------R4
                      \R2------

On Mon, Oct 12, 2009 at 1:19 PM, karim jamali <karim.jamali_at_gmail.com>wrote:

> Dear Gents,
>
> I got it guys.The thing that I wasn't clearly able to understand is that
> there are infact two seperate streams (one from 12.0.0.1/and one from
> 13.0.0.1). For each of those streams the forwarder election took place based
> on:
>
> 1.Better Administrative distance to the source
> 2.Better metric to the source.
> 3.Highest IP address.
>
> Thus for source 12.0.0.1 the forwarder was R2 (as it is connected to it)
> and for source 13.0.0.1 the forwarder was R3.
>
> Thank You for your support & help!
>
> Best Regards,
>
> On Mon, Oct 12, 2009 at 9:34 AM, karim jamali <karim.jamali_at_gmail.com>wrote:
>
>> Dears,
>>
>> R1 is acting as server,R4 as client. I used debug ip mpacket on R4,and
>> saw two packets came from the two interfaces of R1(
>> 12.0.0.1/13.0.0.1). And I used debug ip mpacket on R2 and R3 and both
>> showed a forwarded packet to the segment.
>>
>> Please I really need to understand what is going on thus I will paste the
>> configs:
>>
>> R1
>> ip multicast-routing
>> interface Serial1/0
>> ip address 12.0.0.1 255.255.255.0
>> ip pim sparse-mode
>> serial restart-delay 0
>> clock rate 64000
>> !
>> interface Serial1/1
>> ip address 13.0.0.1 255.255.255.0
>> ip pim sparse-mode
>> serial restart-delay 0
>> clock rate 64000
>>
>> router ospf 1
>> log-adjacency-changes
>> network 0.0.0.0 255.255.255.255 area 0
>>
>> ip pim rp-address 2.2.2.2
>>
>> R2
>>
>> ip multicast-routing
>> interface Loopback0
>> ip address 2.2.2.2 255.255.255.255
>> ip pim sparse-mode
>> ip ospf 1 area 0
>> !
>> interface Ethernet0/0
>> ip address 23.0.0.2 255.255.255.0
>> ip pim sparse-mode
>> no ip mroute-cache
>> half-duplex
>> !
>> interface Ethernet0/1
>> ip address 123.0.0.2 255.255.255.0
>> ip pim sparse-mode
>> no ip mroute-cache
>> half-duplex
>> !
>> interface Serial1/0
>> ip address 12.0.0.2 255.255.255.0
>> ip pim sparse-mode
>> no ip mroute-cache
>> serial restart-delay 0
>> clock rate 64000
>> router ospf 1
>> log-adjacency-changes
>> network 0.0.0.0 255.255.255.255 area 0
>> !
>> ip pim rp-address 2.2.2.2
>> !
>>
>> R3
>>
>> ip multicast-routing
>>
>> interface Ethernet0/0
>> ip address 23.0.0.3 255.255.255.0
>> ip pim sparse-mode
>> no ip mroute-cache
>> half-duplex
>> interface Ethernet0/1
>> ip address 123.0.0.3 255.255.255.0
>> ip pim sparse-mode
>> no ip mroute-cache
>> half-duplex
>>
>> interface Serial1/0
>> ip address 13.0.0.3 255.255.255.0
>> ip pim sparse-mode
>> no ip mroute-cache
>> serial restart-delay 0
>> clock rate 64000
>> router ospf 1
>> log-adjacency-changes
>> network 0.0.0.0 255.255.255.255 area 0
>> ip pim rp-address 2.2.2.2
>>
>> R4
>>
>> ip multicast-routing
>> interface Ethernet0/1
>> ip address 123.0.0.4 255.255.255.0
>> ip pim sparse-mode
>> ip igmp join-group 239.1.1.1
>> half-duplex
>> router ospf 1
>> log-adjacency-changes
>> network 0.0.0.0 255.255.255.255 area 0
>> ip pim rp-address 2.2.2.2
>>
>> When R1 pings the group address (streams traffic destined to the group)
>> 239.1.1.1
>> debug ip mpacket shows on R2,R3,R4
>> R2:
>> *Mar 1 00:07:43.275: IP(0): s=12.0.0.1 (Serial1/0) d=239.1.1.1
>> (Ethernet0/1) id
>> =1, ttl=254, prot=1, len=100(100), mforward
>> *Mar 1 00:07:43.287: IP(0): s=13.0.0.1 (Ethernet0/1) d=239.1.1.1 id=1,
>> ttl=253,
>> prot=1, len=114(100), mroute olist null
>> R3
>> *Mar 1 00:07:15.467: IP(0): s=13.0.0.1 (Serial1/0) d=239.1.1.1
>> (Ethernet0/1) id
>> =1, ttl=254, prot=1, len=100(100), mforward
>> *Mar 1 00:07:15.495: IP(0): s=12.0.0.1 (Ethernet0/1) d=239.1.1.1 id=1,
>> ttl=253,
>> prot=1, len=114(100), mroute olist null
>> R4
>> *Mar 1 00:06:16.187: IP(0): s=13.0.0.1 (Ethernet0/1) d=239.1.1.1 id=1,
>> ttl=253,
>> prot=1, len=114(100), mroute olist null
>> *Mar 1 00:06:16.199: IP(0): s=12.0.0.1 (Ethernet0/1) d=239.1.1.1 id=1,
>> ttl=253,
>> prot=1, len=114(100), mroute olist null
>>
>> This shows that R4 is getting two packets one is being forwarded through
>> R2,and the other through R3.
>>
>> Best Regards,
>>
>> On Sun, Oct 11, 2009 at 10:49 PM, Divin Mathew John <divinjohn_at_gmail.com>wrote:
>>
>>> its probable that after the first packet u switchover to source path
>>> tree[SPT] . try with ip pim spt-thres infini
>>>
>>>
>>> On Sun, Oct 11, 2009 at 6:10 PM, karim jamali <karim.jamali_at_gmail.com>wrote:
>>>
>>>> Dear Divin,
>>>>
>>>> I didn't get you clearly. Are you saying that both routers can forward @
>>>> the same time as this is what is happening with me?
>>>> Please explain more. The thing that is happening with me is that both
>>>> routers (R2,R3) are forwarding multicast traffic to the presumed client
>>>> (R4). However the thing is that I thought that only one forwarder will be
>>>> elected on a common subnet and this router will forward multicast traffic to
>>>> the subnet.
>>>>
>>>> Can you please explain in more detail?
>>>>
>>>> Thank You
>>>>
>>>> Best Regards,
>>>> On Sun, Oct 11, 2009 at 3:08 PM, Divin Mathew John <
>>>> divinjohn_at_gmail.com> wrote:
>>>>
>>>>> yep.
>>>>>
>>>>> highest is the DR. but lowest ip address needn't necessarily forward
>>>>> multicast traffic onto the broadcast domain.1
>>>>>
>>>>> The assert election criteria are as follow in decreasing order of
>>>>> priority:
>>>>>
>>>>> 1- administrative distance to the source S (10.10.10.1)
>>>>>
>>>>> 2- Cost of the route to S (10.10.10.1)
>>>>>
>>>>> 3- Highest multicast interface IP address.
>>>>>
>>>>> refer
>>>>> http://cciethebeginning.wordpress.com/2008/07/16/pim-assert-message/
>>>>>
>>>>> On Sun, Oct 11, 2009 at 3:59 PM, karim jamali <
>>>>> karim.jamali_at_gmail.com> wrote:
>>>>>
>>>>>> Dear Gents,
>>>>>>
>>>>>> I have a confusion regarding multicast. I am running a sparse-mode
>>>>>> scenario
>>>>>> which is shown in the attached visio file.
>>>>>> R1 s1/0 -->R2 s1/0 (12.0.0.0/24)
>>>>>> R1 s1/1 -->R3 s1/0 (13.0.0.0/24)
>>>>>>
>>>>>> R2 fa0/0-->R3 fa0/0(23.0.0.0/24)
>>>>>> R2 fa0/1 -->R3 fa0/1 -->R4 fa0/1 all on the same subnet (123.0.0.0/24
>>>>>> )
>>>>>>
>>>>>> Pim Sparse mode is running on all the common interfaces & neighbor
>>>>>> relationship is formed. On R2, I have a loopback (2.2.2.2) which is
>>>>>> the RP
>>>>>> of the my network.
>>>>>>
>>>>>> Note that I am running OSPF everywhere.
>>>>>>
>>>>>> The confusion is related to the common subnet of R2,R3,R4. From what I
>>>>>> understood, on every common subnet one Querier,and one Forwarder is
>>>>>> elected,
>>>>>> and one Designated Forwarder is Elected.As far as I understand, the
>>>>>> Querier
>>>>>> is the one sending queries asking if anyone wants to join a certain
>>>>>> group.A
>>>>>> forwarder is the one forwarding the stream to the subnet. The
>>>>>> designated
>>>>>> router as far as I understand is the the first layer 3 device which
>>>>>> knows
>>>>>> about the stream from the streamer,and sends a register message to the
>>>>>> RP
>>>>>> notifying it that a source exists. Please correct me if any of my
>>>>>> concepts
>>>>>> is wrong.
>>>>>>
>>>>>> The router with the lowest IP address is the querier and the one with
>>>>>> the
>>>>>> highest IP address is the forwarder. In the scenario I have shown, R1
>>>>>> is the
>>>>>> source, R2's loopback is the RP and R4 ethernet interface has joined a
>>>>>> group
>>>>>> (239.1.1.1). When I ping from R1, I notice that the stream on R4 is
>>>>>> being
>>>>>> received from both R2,and R3?Does this break the concept of forwarder?
>>>>>>
>>>>>> I would be grateful for any help.
>>>>>>
>>>>>> Best Regards,
>>>>>>
>>>>>> KJ
>>>>>>
>>>>>>
>>>>>> Blogs and organic groups at http://www.ccie.net
>>>>>>
>>>>>>
>>>>>> _______________________________________________________________________
>>>>>> Subscription information may be found at:
>>>>>> http://www.groupstudy.com/list/CCIELab.html
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>>
>>>>>
>>>>> Umberto Eco <http://www.quotationspage.com/quote/320.html> - "I felt
>>>>> like poisoning a monk."
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> KJ
>>>>
>>>
>>>
>>>
>>> --
>>>
>>> Sent from Karnataka, India
>>> Umberto Eco <http://www.quotationspage.com/quote/320.html> - "I felt
>>> like poisoning a monk."
>>>
>>
>>
>>
>> --
>> KJ
>>
>
>
>
> --
> KJ
>

-- 
Sent from Karnataka, India
Umberto Eco <http://www.quotationspage.com/quote/320.html>  - "I felt like
poisoning a monk."
Blogs and organic groups at http://www.ccie.net