We are using a Nexus 3172PQ 10gig switch.
we have a multicast feeding coming in on port Eth1/35 which is an access point in vlan 123.
we need the multicast feed to get to ports Eth1/11 and others, but for now just Eth1/11
the mutlicast feed is coming from a vendor - its PTP time, on group 224.0.1.129
it would be complicated and problematic to configure igmp, so we just disabled it.
this nexus does not support "Feature PTP" we do not want or require the accuracy of PTP boundary services on the switch.
however, we see multicast packets arriving at Eth1/35 BUT we do not see them flooded out port Eth1/11.
the ONLY way we can get multicast packets from Eth1/35 to Eth1/11 is to configure a SPAN session, then the server on Eth1/11 CAN see the PTP packets.
a very strange problem.
does the Cisco Nexus 3172PQ have some type of "ASIC" that is intercepting PTP packets? this is a very time consuming problem and we simply need to flood PTP to the entire vlan (vlan 123).
any idea?
here are some basics -
CORESW01# show ip igmp snooping
Global IGMP Snooping Information:
IGMP Snooping disabled
Optimised Multicast Flood (OMF) enabled
IGMPv1/v2 Report Suppression enabled
IGMPv3 Report Suppression disabled
Link Local Groups Suppression enabled
VPC Multicast optimization disabled
IGMP Snooping information for vlan 123
IGMP snooping disabled
Lookup mode: IP
Optimised Multicast Flood (OMF) disabled
IGMP querier none
Switch-querier disabled
IGMPv3 Explicit tracking enabled
IGMPv2 Fast leave disabled
IGMPv1/v2 Report suppression enabled
IGMPv3 Report suppression disabled
Link Local Groups suppression enabled
Router port detection using PIM Hellos, IGMP Queries
Number of router-ports: 0
Number of groups: 0
VLAN vPC function disabled
Active ports:
Eth1/1 Eth1/2 Eth1/3 Eth1/4
Eth1/5 Eth1/6 Eth1/10 Eth1/11
Eth1/12 Eth1/35 Eth1/42 Po1
interface Ethernet1/35
switchport access vlan 123
spanning-tree port type edge
speed 1000
interface Ethernet1/11
switchport access vlan 123
spanning-tree port type edge
(note high number received of multicast - that's PTP packets)
Ethernet1/35 is up
admin state is up, Dedicated Interface
Hardware: 100/1000/10000 Ethernet, address: a03d.6f7e.674a (bia a03d.6f7e.674a)
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, medium is broadcast
Port mode is access
full-duplex, 1000 Mb/s, media type is 1G
Beacon is turned off
Auto-Negotiation is turned on, FEC mode is Auto
Input flow-control is off, output flow-control is off
Auto-mdix is turned off
Rate mode is dedicated
Switchport monitor is off
EtherType is 0x8100
EEE (efficient-ethernet) : n/a
Last link flapped 1d05h
Last clearing of "show interface" counters 23:03:51
0 interface resets
30 seconds input rate 38120 bits/sec, 50 packets/sec
30 seconds output rate 264 bits/sec, 0 packets/sec
Load-Interval #2: 5 minute (300 seconds)
input rate 37.97 Kbps, 47 pps; output rate 224 bps, 0 pps
RX
0 unicast packets 4294590 multicast packets 0 broadcast packets
4294590 input packets 397505711 bytes
0 jumbo packets 0 storm suppression packets
0 runts 0 giants 0 CRC 0 no buffer
0 input error 0 short frame 0 overrun 0 underrun 0 ignored
0 watchdog 0 bad etype drop 0 bad proto drop 0 if down drop
0 input with dribble 0 input discard
0 Rx pause
TX
0 unicast packets 45429 multicast packets 0 broadcast packets
45429 output packets 3909643 bytes
0 jumbo packets
0 output error 0 collision 0 deferred 0 late collision
0 lost carrier 0 no carrier 0 babble 0 output discard
0 Tx pause
note LOW number of multicasts sent on eth1/11 (we see just cdp, and other non-related multicast coming out)
admin state is up, Dedicated Interface
Hardware: 100/1000/10000 Ethernet, address: a03d.6f7e.6732 (bia a03d.6f7e.6732)
MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, medium is broadcast
Port mode is access
full-duplex, 10 Gb/s, media type is 10G
Beacon is turned off
Auto-Negotiation is turned off, FEC mode is Auto
Input flow-control is off, output flow-control is off
Auto-mdix is turned off
Rate mode is dedicated
Switchport monitor is off
EtherType is 0x8100
EEE (efficient-ethernet) : n/a
Last link flapped 22:18:37
Last clearing of "show interface" counters 23:06:00
3 interface resets
30 seconds input rate 24 bits/sec, 0 packets/sec
30 seconds output rate 328 bits/sec, 0 packets/sec
Load-Interval #2: 5 minute (300 seconds)
input rate 24 bps, 0 pps; output rate 248 bps, 0 pps
RX
0 unicast packets 2739 multicast packets 0 broadcast packets
2739 input packets 254727 bytes
0 jumbo packets 0 storm suppression packets
0 runts 0 giants 0 CRC 0 no buffer
0 input error 0 short frame 0 overrun 0 underrun 0 ignored
0 watchdog 0 bad etype drop 0 bad proto drop 0 if down drop
0 input with dribble 0 input discard
0 Rx pause
TX
0 unicast packets 88107 multicast packets 0 broadcast packets
88107 output packets 7787016 bytes
0 jumbo packets
0 output error 0 collision 0 deferred 0 late collision
0 lost carrier 0 no carrier 0 babble 0 output discard
0 Tx pause
thank you!
