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New Member

Multicast traffic is not going downstream

Hi, I am configuring a Multicast Setup , wherein I am sending traffic from IXIA . I am getting mroute entry at CE router but outgoing interface is showing as Null . Bellow are some snapshots . PLease suggest , what could be the problem:

fx-18xx150-ce1-am-atl#sh ip mroute vrf Multi_0

(33.33.33.12, 225.0.0.0), 00:38:50/00:02:46, flags: PT

Incoming interface: FastEthernet0/0.300, RPF nbr 0.0.0.0

Outgoing interface list: Null

5 REPLIES
Cisco Employee

Re: Multicast traffic is not going downstream

Hi Ashutosh,

Yoru outgoing interface is in prune state as of now. I believe the downstream router has sent a prune message updating that it does not need to join this group.

Need to know more about your setup and which protocol you are running? Is the downstream router the router beyond which end hosts exist?

Regards,

Ankur

New Member

Re: Multicast traffic is not going downstream

Hi Ankur,

Thanks for ur reply.

Well I have the setup where I have multicast source ( IXIA )connecetd to one CE and one multicast receiver ( IXIA) connected to other CE . I am running PIM-SSM at core and using sparse mode at interfaces . At receiver CE I am getting mrouter entry properly( plz see bellow ):

72xx167vxr#sh ip mroute vrf Multi_0 33.33.33.12 225.0.0.0

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

(*, 225.0.0.0), 2d18h/stopped, RP 212.31.217.117, flags: SJC

Incoming interface: Null, RPF nbr 0.0.0.0

Outgoing interface list:

GigabitEthernet0/1.300, Forward/Sparse, 2d18h/00:02:57

POS1/1.300, Forward/Sparse, 2d18h/00:02:57

Please suggest.

Regds,

Ashutosh

Cisco Employee

Re: Multicast traffic is not going downstream

Hi Ashutosh,

Your receiver CE still does not show incoming interface and RPF nbr is 0.0.0.0 and your sender CE does not have any outgoing interface listed. So looks to be some commuication problem between 2 CEs. How are they connected?

Is it possible for you to post the config for 2 CEs.

Regards,

Ankur

New Member

Re: Multicast traffic is not going downstream

Hi Ankur ,

Both the CEs are configured in static rp mode ( self loopback ip ).

I am sending the config of both the CEs.

Please find the attached file .

Regds,

Ashutosh

Silver

Re: Multicast traffic is not going downstream

Do you have RP's configured correctly for your mode of operation? Are you using only SSM? And if you are using SSM, are you using correct group numbers for the SSM (SSM have a specific address scope dedicated to them).

As per RFC 4601:

" The range of multicast addresses from 232.0.0.0 to 232.255.255.255 is

currently set aside for source-specific multicast in IPv4. For

groups in this range, receivers should only issue source-specific

IGMPv3 joins. If a PIM router receives a non-source-specific join

for a group in this range, it should ignore it, as described in

Section 4.8."

So if you are using SSM and a group of 225.0.0.0, this could be a problem.

Try using 232.0.0.0 instead

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