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Inbound Packets Being Discarded On Dell 6248 Switch
Hello guys,
I am having an issue on my network. Once in a while icmp echo packets are being lost and this is causing our monitoring system to trigger false alarms.
I have checked the switches interfaces and found that the discarded packets counter is being incremented in one of them.
Flow control is enabled on the interface and there are no Pause Frames being sent.
The duplex on both ends are correct so are the port speeds.
The switch firmware is 3.3.9.1 and the model is a PowerConnect 6248.
show statistics ethernet 1/g48
Total Packets Received (Octets)................ 2019770477
Packets Received 64 Octets..................... 945800
Packets Received 65-127 Octets................. 1105872
Packets Received 128-255 Octets................ 152970
Packets Received 256-511 Octets................ 445738
Packets Received 512-1023 Octets............... 155436
Packets Received 1024-1518 Octets.............. 414040
Packets Received > 1518 Octets................. 634118
Packets RX and TX 64 Octets.................... 946019
Packets RX and TX 65-127 Octets................ 3294655
Packets RX and TX 128-255 Octets............... 235082
Packets RX and TX 256-511 Octets............... 893732
Packets RX and TX 512-1023 Octets.............. 311408
Packets RX and TX 1024-1518 Octets............. 436671
Packets RX and TX 1519-2047 Octets............. 873826
Packets RX and TX 2048-4095 Octets............. 0
Packets RX and TX 4096-9216 Octets............. 0
Total Packets Received Without Errors.......... 3853974
Unicast Packets Received....................... 3421088
Multicast Packets Received..................... 211575
Broadcast Packets Received..................... 221311
--More-- or (q)uit
Receive Packets Discarded...................... 506
Total Packets Received with MAC Errors......... 0
Jabbers Received............................... 0
Fragments/Undersize Received................... 0
Alignment Errors............................... 0
FCS Errors..................................... 0
Overruns....................................... 0
802.3x Pause Frames Received................... 0
Unacceptable Frame Type........................ 0
Total Packets Transmitted (Octets)............. 858789293
Packets Transmitted 64 Octets.................. 219
Packets Transmitted 65-127 Octets.............. 2188783
Packets Transmitted 128-255 Octets............. 82112
Packets Transmitted 256-511 Octets............. 447994
Packets Transmitted 512-1023 Octets............ 155972
Packets Transmitted 1024-1518 Octets........... 22631
Packets Transmitted > 1518 Octets ............. 239708
Max Frame Size................................. 1518
Total Packets Transmitted Successfully......... 3137419
Unicast Packets Transmitted.................... 3034928
--More-- or (q)uit
Multicast Packets Transmitted.................. 1628
Broadcast Packets Transmitted.................. 100863
Transmit Packets Discarded..................... 0
Total Transmit Packets Discarded............... 0
Single Collision Frames........................ 0
Multiple Collision Frames...................... 0
Excessive Collision Frames..................... 0
802.3x Pause Frames Transmitted................ 0
GVRP PDUs received............................. 0
GVRP PDUs Transmitted.......................... 0
GVRP Failed Registrations...................... 0
BPDU: sent 0, received 0
EAPOL Frames Transmitted....................... 0
EAPOL Start Frames Received.................... 0
Thanks in advance.
MauricioUsatai
12 Posts
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July 21st, 2016 10:00
Humm,
We have changed our remote office wan link duo to an outage and the interface stop counting errors. Everything is the same: traffic, applications, etc. Not a clue about what happened since there is a linux machine between the carrier equipment and the switch (bad packets would be dropped in the linux machine interface).
We are now addressing the carrier for explanations/solutions.
Thank you for your time!
Anonymous
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July 11th, 2016 14:00
Based on the counters recorded, I do not see any indication as so why these packets would be discarded. You might check the switch logs to be sure there are no errors that accommodate the dropped packets. Performing a packet capture on that interface would provide a lot of insight into what packet is being received, and perhaps why it is being discarded.
On a side note, the firmware is a couple years out of date. Getting the firmware up to date may help with overall operability.
http://dell.to/28ZVkTY
MauricioUsatai
12 Posts
0
July 12th, 2016 07:00
Hello Daniel,
Thanks for your reply!
The logs does not give any clue as well, but I am seeing a lot of dropped messages on the log buffer:
#show logging
Logging is enabled
Console Logging: level info. Console Messages: 53546 Dropped.
Buffer Logging: level notice. Buffer Messages: 134 Logged,
File Logging: level info. File Messages: 53547 Dropped.
CLI Command Logging : disabled
Web Session Logging : disabled
SNMP Set Command Logging : disabled
Syslog server X.X.X.X logging: warning. Messages: 0 dropped
83 Messages dropped due to lack of resources.
Does info level messages can give me any info I dont have already? Cause I don't think so.
Thanks in advance.
MauricioUsatai
12 Posts
0
July 12th, 2016 08:00
No discards on IP stats whatsoever. I found this IpInAddrErrors but it is not incrementing at all. At least not at the same rate as the inbound packets discarded counter.
#show ip stats
IpInReceives................................... 5216756
IpInHdrErrors.................................. 0
IpInAddrErrors................................. 315707
IpForwDatagrams................................ 0
IpInUnknownProtos.............................. 0
IpInDiscards................................... 0
IpInDelivers................................... 3704280
IpOutRequests.................................. 7498758
IpOutDiscards.................................. 0
IpOutNoRoutes.................................. 0
IpReasmTimeout................................. 60
IpReasmReqds................................... 0
IpReasmOKs..................................... 0
IpReasmFails................................... 0
IpFragOKs...................................... 0
IpFragFails.................................... 0
IpFragCreates.................................. 0
IpRoutingDiscards.............................. 0
IcmpInMsgs..................................... 200667
IcmpInErrors................................... 0
--More-- or (q)uit
IcmpInDestUnreachs............................. 12207
IcmpInTimeExcds................................ 0
IcmpInParmProbs................................ 0
IcmpInSrcQuenchs............................... 0
IcmpInRedirects................................ 0
IcmpInEchos.................................... 188452
IcmpInEchoReps................................. 8
IcmpInTimestamps............................... 0
IcmpInTimestampReps............................ 0
IcmpInAddrMasks................................ 0
IcmpInAddrMaskReps............................. 0
IcmpOutMsgs.................................... 200602
IcmpOutErrors.................................. 0
IcmpOutDestUnreachs............................ 12142
IcmpOutTimeExcds............................... 0
IcmpOutParmProbs............................... 0
IcmpOutSrcQuenchs.............................. 0
IcmpOutRedirects............................... 0
IcmpOutEchoReps................................ 188452
IcmpOutTimestamps.............................. 0
IcmpOutTimestampReps........................... 0
IcmpOutAddrMasks............................... 0
Anonymous
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July 12th, 2016 08:00
That is interesting that is says it is dropping because of lack of resources. It might be a good idea to take a look at the resources during packet loss.
# show process cpu
# show memory cpu
If the resources are being used up, it could explain the packet loss.
MauricioUsatai
12 Posts
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July 12th, 2016 08:00
Just to clear this up, the packet dropping occurs all the time. About 1/s.
There are plenty of resources. There is not much traffic either on all interfaces.
The greatest load on the switch is the camera network traffic (Video stream). There is any way to check the buffers utilization?
#show cpu utilization
...output omitted...
Total CPU Utilization 13.88% 22.53% 20.50%
#show memory cpu
Total Memory................................... 262144 KBytes
Available Memory Space......................... 23915 KBytes
Anonymous
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July 12th, 2016 08:00
The CPU and memory usage look fine to me. I am not aware of a command to check the buffer utilization. We can use the command, console>show ip stats, to check for IpInDiscards and IpOutDiscards. Those would be an indicator of lack of buffer space.
Getting a packet capture of the interface is still a good way to gain further info on the packets being dropped.