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IOS-XR 5.1.3 input drops / unrecognized upper-level protocol

Hi Community

I have a lot of input, and unrecognized upper-level protocol error on one of my GigabitEthernet Interface.

In the drop queue, I can see they are comming from the follwing queue: PARSE_DROP_IPV6_DISABLED .

I don't have ipv6 enabled on that partical Interface, so why will that ipv6 traffic NOT discard?


GigabitEthernet0/0/0/19 is up, line protocol is up
Interface state transitions: 33
Hardware is GigabitEthernet, address is d46d.502b.004b (bia d46d.502b.004b)
Description: SwissIX Peering Switch;M;NET;V-1;150216;bosshaad;Peering Switch SwissIX Equinix4
Internet address is
MTU 1514 bytes, BW 1000000 Kbit (Max: 1000000 Kbit)
reliability 255/255, txload 146/255, rxload 3/255
Encapsulation ARPA,
Full-duplex, 1000Mb/s, link type is force-up
output flow control is off, input flow control is off
loopback not set,
ARP type ARPA, ARP timeout 00:10:00
Last input 00:00:00, output 00:00:00
Last clearing of "show interface" counters 05:24:46
5 minute input rate 15525000 bits/sec, 20408 packets/sec
5 minute output rate 573356000 bits/sec, 62546 packets/sec
412883756 packets input, 43777551634 bytes, 1097223 total input drops
2189 drops for unrecognized upper-level protocol
Received 1398016 broadcast packets, 1106594 multicast packets
0 runts, 0 giants, 0 throttles, 0 parity
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
1358510576 packets output, 1568499475524 bytes, 2298 total output drops
Output 0 broadcast packets, 0 multicast packets
0 output errors, 0 underruns, 0 applique, 0 resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions


Thanks for your feedback

Cisco Employee

Hello Adrian

These packets will be dropped on the interface and will increment 'total input drops'

PARSE_DROP_IPV6_DISABLED (IPv6 packets dropped on receipt from Ethernet due to IPv6 not enabled on interface/subinterface) 

You can check the descriptions from these counters

sh controllers np descriptions location 0/x/cpu0

RP/0/RSP0/CPU0:ASR9001-A#show controllers np descriptions location 0/0/CPU0 | inc PARSE_DROP_IPV6_DISABLED
Mon Dec 14 14:39:02.405 UTC
PARSE_DROP_IPV6_DISABLED Drop L3 IPv6 packets dropped on receipt from Ethernet due to IPv6 not enabled on interface/subinterface




Thanks for your quick feedback, I’m aware that these drops are coming from an ipv6 speaker.

But my question is, how can I avoid the interface counter from incrementing these errors.

I mean ours monitoring does not really like this amount of errors, and I don’t like it’s too J


hi Adrian,

today it's not possible to exclude these drops from contributing to the total input drop counter. We have an enhancement in the pipeline that will do exactly this:

As a workaround for the current issue you are observing you could enable IPv6 on the interface and apply an IPv6 ACL that drops all traffic.




Hi Aleksandar


Many thanks for you feedback, I can leave with that workaround, it’s not perfect but better than no option.


Have a good day



To amplify what Aleksandar says, graphing input drops and categorizing them all as errors is not a "good idea".  You'll get many many things that go into that counter, and not all of them are a problem that can be fixed.  

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