Cisco ASR920 port have Unknown protocol and output drops to Meraki

[CiscoBuddy1]

We have unknown protocol and output drops to Meraki, cdp is enabled but not lldp. Does any have face this kind of issue?

GigabitEthernet0/0/x is up, line protocol is up
Hardware is 24xGE-4x10GE-FIXED, address is 706d.155c.af9x (bia 706d.155c.af9x)
Description: xxx
Internet address is x.x.x.x/30
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 2/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full Duplex, 1000Mbps, link type is auto, media type is LX
output flow-control is unsupported, input flow-control is on
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:05, output 00:00:08, output hang never
Last clearing of "show interface" counters 17:49:20
Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 1709362
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 2735000 bits/sec, 859 packets/sec
5 minute output rate 11649000 bits/sec, 1366 packets/sec
61710196 packets input, 32652813530 bytes, 0 no buffer
Received 1889 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
6 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 2110 multicast, 0 pause input
116226700 packets output, 126164898257 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
2102 unknown protocol drops
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
xxx#

[MHM Cisco World]

Dont worry' if traffic not effect then it can protocol like cdp or dtp send by SW and ASR drop it.

MHM

[CiscoBuddy1]

i just enabled lldp run and now i have no unknown protocol but output drops keep increasing.

[MHM Cisco World]

I will give some trick I get from TAC' 

Check the output rate with BW of link' 

The output rate is higher than BW of link that why output drop is increasing' ypu need to increase BW.

For unknown' glad issue is solve by enable lldp.

MHM

[CiscoBuddy1]

i it is 1000 megabit (1 gig ) SFP by default, what to increase?

[MHM Cisco World]

Friend it 1 mega' and your output rate more than 1.1 mega.

Use PO and check then output.

Goodluck 

MHM

[CiscoBuddy1]

can you please highlight where do you see 1 mega? and what do you mean by PO?

[MHM Cisco World]

Sorry it was late yesterday so I wrongly see number 

Anyway 

There is output drop in router' output drop come from two issue 

1- over subscription <<- this what I guess firstly 

2- overload by packet fragment 

For more info check this guide 

https://www.cisco.com/c/en/us/support/docs/routers/asr-1000-series-aggregation-services-routers/110531-asr-packet-drop.html

MHM

[liviu.gheorghe]

The output rate of the interface is actually 11.649 Mbps which less than the interface bandwidth.

Can you also provide the show interface for the other end of the interface Gi0/0?

Do you have some QoS configured on interface Gi0/0?

[CiscoBuddy1]

i dont have access to other end.

also i dont have QoS configured. below is my port config.

interface GigabitEthernet0/0/12
description x
ip vrf forwarding xx
ip address x.x.x.x 255.255.255.252
no ip redirects
no ip unreachables
no ip proxy-arp
negotiation auto
end

[liviu.gheorghe]

Your drop ratio is around 1.4% which a little higher than it should be - below 1% you should't worry about it.

Drops can happen for a lot of reasons - bursty traffic, unknown protocols that the router doesn't know how to handle for example.

I would do a clear counters Gi 0/0 and see how it shows after a day. Post the output here.

[paul driver]

Hello
if that rtr is connected via any l2 switch/port
then disable DTP  on that switchport as that is one reason why the rtr would be seeing unknown packets 
On the switchport 
switchport mode access 
or
switchport nonnegotiate

Additionally check your cabling..