Hello.
I'm pretty new to multicast, but I've been thrown into a pretty big network that recently replaced a pair of old catalyst switches with a pair of nexus switches using a VPC and I'm hoping I'm just missing something simple. Through a lot of time spent with cisco, we found that the VPC isn't supported with multicast, so the proposed solution was to create routed layer 3 ports on the nexus and connect those to our core Catalyst 6509 switch for multicast only. All of our typical traffic uses the VPC and a switchport trunk. Multicast worked fine before swapping out the switches, so I'm focusing mostly on the connection between these devices to find the problem. For the purposes of this question, I'm focusing on a single Nexus switch and my core 6509. To add to the fun, all of the multicast is within a vrf called Manufacturing.
First the facts.
Multicast group: 239.255.255.250
Multicast Server(source): 10.180.4.48
Server comes into the core 6509 on vlan 643 (Not the same subnet as the server).
Multicast traffic should leave the core on port Te2/3/8 (10.180.254.53).
Multicast traffic should arrive on the nexus switch on port Eth4 (10.180.254.54)
Multicast traffic goes out VLANs 208, 221, and 503
Core interface config:
interface TenGigabitEthernet2/3/8
description Multicast Link to 10.180.1.105 Eth1/4
no switchport
ip vrf forwarding Manufacturing
ip address 10.180.254.53 255.255.255.252
ip pim sparse-mode
end
Nexus interface config:
interface Ethernet1/4
description L3 P2P to Core 2/3/8
no switchport
vrf member Manufacturing
no ip redirects
ip address 10.180.254.54/30
no ipv6 redirects
ip pim sparse-mode
mroute table on the core:
show ip mroute vrf Manufacturing 239.255.255.250 10.180.4.48
(10.180.4.48, 239.255.255.250), 01:12:46/00:03:26, flags: LJT
Incoming interface: Vlan643, RPF nbr 10.180.126.10, Partial-SC
Outgoing interface list:
TenGigabitEthernet2/3/8, Forward/Sparse, 01:12:39/00:02:54, H
Vlan844, Forward/Sparse, 01:12:46/00:02:06, H
You can see that there is traffic coming into the core with the following command, and I can see it incrementing if I run it more than once.
show ip mroute vrf Manufacturing 239.255.255.250 count
Group: 239.255.255.250, Source count: 10, Packets forwarded: 68, Packets received: 68
RP-tree: Forwarding: 0/0/0/0, Other: 0/0/0
Source: 10.180.4.48/32, Forwarding: 68/1/124/0, Other: 68/0/0
Below you can see the mroute table on the nexus. It only has the (*,G). You can also see that the count is stuck at 3 and doesn't move.
show ip mroute 239.255.255.250 detail vrf Manufacturing
(*, 239.255.255.250/32), uptime: 5w3d, igmp(3) ip(0) pim(0)
RPF-Source: 10.180.250.1 [0/1]
Data Created: No
Locally joined
VPC Flags
RPF-Source Forwarder
Stats: 8528/3995003 [Packets/Bytes], 0.000 bps
Stats: Inactive Flow
Incoming interface: Ethernet1/4, RPF nbr: 10.180.254.53
Outgoing interface list: (count: 3) (bridge-only: 0)
Vlan503, uptime: 5w3d, igmp (vpc-svi)
Vlan208, uptime: 5w3d, igmp (vpc-svi)
Vlan221, uptime: 5w3d, igmp (vpc-svi)
If I ping from the core to the multicast ip, the nexus responds:
ping vrf Manufacturing 239.255.255.250
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 239.255.255.250, timeout is 2 seconds:
Reply to request 0 from 10.180.254.54, 28 ms
Reply to request 0 from 10.180.2.1, 56 ms
Reply to request 0 from 10.180.254.54, 48 ms
Reply to request 0 from 10.180.44.1, 48 ms
Reply to request 0 from 10.180.254.54, 48 ms
Reply to request 0 from 10.180.126.9, 48 ms
Reply to request 0 from 10.180.254.54, 48 ms
Reply to request 0 from 10.180.250.1, 48 ms
on the core, if I run a debug ip mpacket detail 239.255.255.250, I see the following two lines every 4-6 seconds which matches the incrementing mroute count.
Jan 8 16:49:00.179: IP(1): MAC sa=1cdf.0f03.b180 (Vlan643)
Jan 8 16:49:00.183: IP(1): IP tos=0xB8, len=124, id=11859, ttl=9, prot=17
Any ideas? Or troubleshooting steps to figure this out? I'd be very grateful for any help. I've been working on this for months.
Andy
