Hi All, We have set of PLC/SCADA devices that is connected to the Cisco switch. All those ports are configured with Same VLAN that it has to be. We can ping the switch from layer 3 perspective but all these end devices are not able to communicate among themselves, when checking the switch access port details I noticed "unknown protocol drops " are increasing for every 10 seconds approximately . I reckon this could be the issue here , have anyone faced the similar kind of issue and what methods have been taken to fix the same ?
Below the output of one of the Interface where it shows constant increase in unknown protocol drops
GigabitEthernet1/0/16 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is 7c21.0ea0.ad90 (bia 7c21.0ea0.ad90)
MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s, media type is 10/100/1000BaseTX
input flow-control is on, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:01, output 00:00:00, output hang never
Last clearing of "show interface" counters 00:23:34
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: Class-based queueing
Output queue: 0/40 (size/max)
5 minute input rate 34000 bits/sec, 20 packets/sec
5 minute output rate 148000 bits/sec, 124 packets/sec
24892 packets input, 5083284 bytes, 0 no buffer
Received 3773 broadcasts (3725 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 3725 multicast, 0 pause input
0 input packets with dribble condition detected
177738 packets output, 26083788 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
1178 unknown protocol drops //Look here//
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out
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Next out out taken for the same port after 5 seconds approximately:
GigabitEthernet1/0/16 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is 7c21.0ea0.ad90 (bia 7c21.0ea0.ad90)
MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s, media type is 10/100/1000BaseTX
input flow-control is on, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:01, output 00:00:00, output hang never
Last clearing of "show interface" counters 00:24:51
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: Class-based queueing
Output queue: 0/40 (size/max)
5 minute input rate 34000 bits/sec, 20 packets/sec
5 minute output rate 149000 bits/sec, 124 packets/sec
26286 packets input, 5368447 bytes, 0 no buffer
Received 3981 broadcasts (3931 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 3931 multicast, 0 pause input
0 input packets with dribble condition detected
187731 packets output, 27548620 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
1242 unknown protocol drops //Look here//
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out
checked the port status and all the ports shows Up and running fine but noticed this is weird .
