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No Multicast over Tunne?

KGrev
Level 4
Level 4

Hi,

 

I have an LTE router connected over vpn. I have a working gre tunnel within this connection. I can force traffic across the tunnel and load certain pages on a connected laptop on g0 interface. But instead I'd like to only use the tunnel for multicast traversal. Currently the router does see the distant end of the tunnel as a pim neighbor (ip - A.B.44.1), however, multicast isnt working. When I try to pull a feed I dont see any entries in the mroutes for the group. Also "debug ip pim" does not show any activity for the groups i try to stream just rp discovery for 224.0.1.40. Attached is a sample of the configuration of the router.

Any help is greatly appreciated.

23 Replies 23

Harold Ritter
Cisco Employee
Cisco Employee

Hi @KGrev ,

Do you see an active receiver?

"show ip igmp group" and make sure you see the receiver. If you see an active receiver via igmp, you should see it in the "show ip mroute" output.

Regards,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

KGrev
Level 4
Level 4

Good Morning @Harold Ritter ,

I don't think I see an active receiver. It only shows 224.0.1.40 for that command.

I did double check that VLC wasn't an issue and move the laptop to a known working local connection and the video started streaming when it became connected and local ip changed.

 


LTE_Router#show ip igmp groups
IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter Group Accounted
224.0.1.40 GigabitEthernet0 17:58:49 00:02:05 A.B.44.9

LTE_Router#show ip pim int
Address Interface Ver/ Nbr Query DR DR Mode Count Intvl Prior
A.B.44.2 Tunnel14 v2/S 0 30 1 0.0.0.0
A.B.44.9 GigabitEthernet0 v2/S 0 30 1 A.B.44.9


LTE_Router#show ip mroute
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, E - Extranet,
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,
G - Received BGP C-Mroute, g - Sent BGP C-Mroute,
N - Received BGP Shared-Tree Prune, n - BGP C-Mroute suppressed,
Q - Received BGP S-A Route, q - Sent BGP S-A Route,
V - RD & Vector, v - Vector, p - PIM Joins on route,
x - VxLAN group
Outgoing interface flags: H - Hardware switched, A - Assert winner, p - PIM Join
Timers: Uptime/Expires
Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 224.0.1.40), 19:46:14/00:02:46, RP C.D.236.254, flags: SJCL
Incoming interface: Tunnel14, RPF nbr 0.0.0.0, Mroute
Outgoing interface list:
GigabitEthernet0, Forward/Sparse, 17:59:16/00:02:46

 

 

Thank you for your response Harold.

Hi @KGrev ,

The fact that you don't see the IGMP group is where you need to focus. Is the receiver PC connected to Gig0? Is there a switch behind that port?

Regards,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

Thanks @Harold Ritter 

The Laptop is connected to G0. It has connectivity and can ping its gateway on the lte router and ping the RP within the network.

Here is the laptop pinging the multicast group.

003881: May 2 2024 08:50:43.199 PDT: PIM(0): Check RP C.D.236.254 into the (*, 239.22.22.22) entry
003882: May 2 2024 08:50:43.199 PDT: PIM(0): Building Triggered (*,G) Join / (S,G,RP-bit) Prune message for 239.22.22.22
003883: May 2 2024 08:50:43.199 PDT: PIM(0): Adding register encap tunnel (Tunnel0) as forwarding interface of (A.B.44.10, 239.22.22.22).
LTE_Router#show ip mroute
IP Multicast Routing Table

Outgoing interface flags: H - Hardware switched, A - Assert winner, p - PIM Join
Timers: Uptime/Expires
Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.22.22.22), 00:00:06/stopped, RP C.D.236.254, flags: SPF
Incoming interface: Tunnel14, RPF nbr A.B.44.1, Mroute
Outgoing interface list: Null

(A.B.44.10, 239.22.22.22), 00:00:06/00:02:53, flags: PFT
Incoming interface: GigabitEthernet0, RPF nbr 0.0.0.0, Registering
Outgoing interface list: Null

(*, 224.0.1.40), 20:51:28/00:02:34, RP C.D.236.254, flags: SJCL
Incoming interface: Tunnel14, RPF nbr A.B.44.1, Mroute
Outgoing interface list:
GigabitEthernet0, Forward/Sparse, 19:04:31/00:02:34

Hi @KGrev ,

As I mentioned in my previous message, the issue is definitely related to the router not seeing the multicast group in IGMP. This is where you need to start the troubleshooting. 

Pinging from the PC to the router is one step, but beyond that you need to check why the router doesn't seem to be receiving the IGMP membership report from the PC.

Regards,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

Sorry @Harold Ritter I misunderstood you. So the router does not populate "show ip igmp groups" if it cannot see the groups from the pim neighbor or rp?

On another note, I just noticed that sometimes when I do "show ip pim neighbor", I no longer have a neighbor.

Hi @KGrev ,

The issue does not have anything to do with PIM, but strictly with IGMP for now. The router first need to receive an IGMP report message from the receiver (PC), before it starts population the "mroute". This is why I suggested to start the troubleshooting between the router and the PC.

Regards,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

@Harold Ritter  Ok I see, thanks for correcting me. If im focusing on the laptop. I just double checked with wireshark on the ethernet link that I only see 4 igmpv2 packets when I try to pull the stream. This is the only activity I see. If its not multicast if is able to pull other services while connected to g0 with the cellular interface on the laptop turned off.

Hi @KGrev ,

I just double checked with wireshark on the ethernet link that I only see 4 igmpv2 packets when I try to pull the stream.

Can you enable "deb ip igmp" on the router and see if the IGMP report messages are being received from the host?

Regards,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

@Harold Ritter 

Here is what debug is showing. I dont see anything for the multicast stream im going for.

000062: May 2 2024 13:36:04.007 PDT: IGMP(0): Send v2 general Query on GigabitEthernet0
000063: May 2 2024 13:36:04.007 PDT: IGMP(0): Set report delay time to 6.6 seconds for 224.0.1.40 on GigabitEthernet0
LTE_Router#
000064: May 2 2024 13:36:10.668 PDT: IGMP(0): Send v2 Report for 224.0.1.40 on GigabitEthernet0
000065: May 2 2024 13:36:10.668 PDT: IGMP(0): Received v2 Report on GigabitEthernet0 from A.B.44.9 for 224.0.1.40
000066: May 2 2024 13:36:10.668 PDT: IGMP(0): Received Group record for group 224.0.1.40, mode 2 from A.B.44.9 for 0 sources
000067: May 2 2024 13:36:10.668 PDT: IGMP(0): Updating EXCLUDE group timer for 224.0.1.40
000068: May 2 2024 13:36:10.668 PDT: IGMP(0): MRT Add/Update GigabitEthernet0 for (*,224.0.1.40) by 0
LTE_Router#
000069: May 2 2024 13:36:20.357 PDT: IGMP(0): Send v2 general Query on Tunnel14
LTE_Router#
000070: May 2 2024 13:37:04.036 PDT: IGMP(0): Send v2 general Query on GigabitEthernet0
000071: May 2 2024 13:37:04.036 PDT: IGMP(0): Set report delay time to 3.6 seconds for 224.0.1.40 on GigabitEthernet0
LTE_Router#
000072: May 2 2024 13:37:07.696 PDT: IGMP(0): Send v2 Report for 224.0.1.40 on GigabitEthernet0
000073: May 2 2024 13:37:07.696 PDT: IGMP(0): Received v2 Report on GigabitEthernet0 from A.B.44.9 for 224.0.1.40
000074: May 2 2024 13:37:07.696 PDT: IGMP(0): Received Group record for group 224.0.1.40, mode 2 from A.B.44.9 for 0 sources
000075: May 2 2024 13:37:07.696 PDT: IGMP(0): Updating EXCLUDE group timer for 224.0.1.40
000076: May 2 2024 13:37:07.696 PDT: IGMP(0): MRT Add/Update GigabitEthernet0 for (*,224.0.1.40) by 0
LTE_Router#
000077: May 2 2024 13:37:20.386 PDT: IGMP(0): Send v2 general Query on Tunnel14
LTE_Router#
000078: May 2 2024 13:38:04.064 PDT: IGMP(0): Send v2 general Query on GigabitEthernet0
000079: May 2 2024 13:38:04.064 PDT: IGMP(0): Set report delay time to 9.8 seconds for 224.0.1.40 on GigabitEthernet0
LTE_Router#
000080: May 2 2024 13:38:13.927 PDT: IGMP(0): Send v2 Report for 224.0.1.40 on GigabitEthernet0
000081: May 2 2024 13:38:13.927 PDT: IGMP(0): Received v2 Report on GigabitEthernet0 from A.B.44.9 for 224.0.1.40
000082: May 2 2024 13:38:13.927 PDT: IGMP(0): Received Group record for group 224.0.1.40, mode 2 from A.B.44.9 for 0 sources
000083: May 2 2024 13:38:13.927 PDT: IGMP(0): Updating EXCLUDE group timer for 224.0.1.40
000084: May 2 2024 13:38:13.927 PDT: IGMP(0): MRT Add/Update GigabitEthernet0 for (*,224.0.1.40) by 0

Thanks @KGrev .

Is that with the PC trying to pull the multicast stream?

Is the Wireshark capture showing the multicast group you are trying to pull?

Regards,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

@Harold Ritter, yes sir, while the pc is starting and stopping requests for a 239.22.22.22 multicast stream via VLC player.

  I grabbed a completely different laptop just for a sanity check. It isnt hardened like the other laptop and running an updated version of windows. Same effect. Did not see any traffic regarding 239.22.22.22. This tactic does work while plugged into the local office lan.

Thanks @KGrev ,

> yes sir, while the pc is starting and stopping requests for a 239.22.22.22 multicast stream via VLC player.

Did you verify using Wireshark or "debug ip igmp"? 

If the PC does not send the IGMP membership report for the mcast group 239.22.22.22, it will definitely not work. 

Is the PC directly connected to port gi0 or via a switch?

One thing you could try would be to set "ip igmp static-group 239.22.22.22" on the router gi0 to force multicast traffic down the gi0 interface. This would not solve the IGMP issue though. 

Regards,

 

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

@Harold Ritteryes sir, both laptops show "membership report group 239.22.22.22" in their wireshark. The laptops are connected directly to the router on g0 while testing.

Its strange that these laptops will pull a multicast feed with this method while connected locally. Is there some sort of global command i've missed that is making the router totally disregard igmp requests?

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