What cause event on tools monitoring is "Port inbound Discard High (Device Congestion)" . everyday events always appear on tools monitoring only for one Vlan.
I went looking for input errors on the port, but there are none, and the interface is running normal. So, what is a discard, and how do I troubleshoot it?
I was looking up a similar case for ASR-9001 platform IOS XR code 4.3.2 and alerts looked like below:
As I further checked on this the interface counters looked clean and there were no drops and signs of congestion/discards. All of the ingress and egress packets were forwarded in normal way and I could also see no dot1q frames were identified on the interface that may have been dropped due to wrong VLAN encapsulations as per the counter explanations from below URL:
“InDiscards” are almost always caused by a port that is receiving tagged frames for a VLANID that that port is not a member of.
So as per the observations the reported alarm seems false and could not be related to counters on the interfaces:
The interface stats look clean and I do not see any discards for legitimate traffic:
Statistics for interface GigabitEthernet x/x/x/x (cached values):
Input total bytes = 33080084
Input good bytes = 33080084
Input total packets = 184799
Input 802.1Q frames = 0
Input pause frames = 0
Input pkts 64 bytes = 67504
Input pkts 65-127 bytes = 57148
Input pkts 128-255 bytes = 36526
Input pkts 256-511 bytes = 3825
Input pkts 512-1023 bytes = 16717
Input pkts 1024-1518 bytes = 3079
Input pkts 1519-Max bytes = 0
Input good pkts = 184799
Input unicast pkts = 98431
Input multicast pkts = 28492
Input broadcast pkts = 57876
Input drop overrun = 0
Input drop abort = 0
Input drop invalid VLAN = 0
Input drop invalid DMAC = 0
Input drop invalid encap = 0
Input drop other = 0
Input error giant = 0
Input error runt = 0
Input error jabbers = 0
Input error fragments = 0
Input error CRC = 0
Input error collisions = 0
Input error symbol = 0
Input error other = 0
Input MIB giant = 0
Input MIB jabber = 0
Input MIB CRC = 0
Output total bytes = 30648266
Output good bytes = 30648266
Output total packets = 96223
Output 802.1Q frames = 0
Output pause frames = 0
Output pkts 64 bytes = 593
Output pkts 65-127 bytes = 22117
Output pkts 128-255 bytes = 36792
Output pkts 256-511 bytes = 16198
Output pkts 512-1023 bytes = 17120
Output pkts 1024-1518 bytes = 3403
Output pkts 1519-Max bytes = 0
Output good pkts = 96223
Output unicast pkts = 95850
Output multicast pkts = 373
Output broadcast pkts = 0
Output drop underrun = 0
Output drop abort = 0
Output drop other = 0
Output error other = 0
"Drops for unrecognized upper-level protocol" means that we've received
packets of a type that you haven't configured and therefore don't have a
handler for in the interface protocol handling chain.
That may be (and most likely is) expected and purely cosmetic.
- other side (switch) has CDP configured but you don't have CDP configured on this end
- someone on the Ethernet is sending IS-IS hellos but you don't have IS-IS configured on this end
- someone on the Ethernet is sending IPv6 neigbor discovery packets but you don't have IPv6 configured on this end
It may be worth checking:
- do these packets increment periodically (i.e. one packet every 30 sec or so)?
- are there any obvious features (CDP is a good candidate) that you haven't configured but the far-end (switch, or if it's a crosslink, then
the connected peer) has?
Otherwise capture & decode the packets, and perhaps reviewing the config will already give the answer in a couple of seconds.
If a 7600/ 6500 port is connected to the ASR9000 and input error increment due to 'unrecognized upper-level protocol', then to avoid various l2 packets reaching ASR9000, you can use:
switchport nonegotiate - disable Dynamic Trunk Protocol (DTP) on the port
no cdp enable - to disable running Cisco Discovery Protocol (CDP)
no vtp - to disable sending VLAN Trunking Protocol(VTP) frame
spanning-tree bpdfilter enable - To enable BPDU filtering on the interface
UDLD: If you are running CatOS try “set udld disable x/y” or “udld port disable” under the interface if you have IOS on the 6500.
LLDP: (new addition) switches by default have lldp enabled that could be, like CDP, be perceived as an unrecognized upper level protocol on the ASR9000.
I have this problem too, since i was upgrade my firmware ACI, the discards was appears, usually the disacrds could be hide with bcm-shell command, but after upgraded the firmware the bcm-shell command couldn't affected to hide the discards.
Is there any others solution for these issues?.