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October 27th, 2023 04:50

High frame discards on interfaces

Hi,

Having some issues with clients on N3248x-on switches. All client facing ports are showing very high counters for "Total received frames not forwarded".

As an example, this is 45 mins after clearing counters:

Total received frames not forwarded............ 1195490448
Total frames transmitted successfully..........    171725893

This isn't showing on upstream interface, just the client ports.

Clients on older switches (n3048), doing very much the same thing, are not showing this behavior.

The ports are just access ports in a vlan, not vlan tagged.

Has anyone else seen this behavior?

Moderator

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2.1K Posts

October 27th, 2023 09:29

Hi, Could you check VLAN config of your client ports, please ensure they are in the correct mode(access or trunk) and that they are allowed to forward traffic from VLANs . Because if there is a mismatch, you might see untagged frames or frames with unknown VLAN tags being discarded by ports. Probably good to check QoS config of ports. You can check if they have enough bandwidth resources to handle traffic from devices. If you see any drops or congestion on your queues, you can adjust QoS settings of ports. If you see alignment errors on ports which can lead to discards. You can check speed and duplex settings of client ports and make sure they match settings of devices.

October 30th, 2023 01:18

The client ports are access ports in the vlan, like so:

!
interface Te1/0/1
switchport access vlan 10
exit
!

No QoS config on these ports.

Bandwidth wise, I have a test running with a single 1Gb client connected and the uplink is 25G. Discards etc look normal on the uplink... but the access port shows total received frames not forwarded as 7x the counter for frames forwarded successfully.

Clients are 1gb full duplex, so that is all in alignment as well.

(edited)

Moderator

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3K Posts

30-10-2023 08:25 AM

Hi,

 

Can you try these commands to check if it improves the issue:

 

interface Te1/0/1
switchport access vlan 10

spanning-tree portfast

storm-control broadcast
exit

 

DELL-Joey C

Social Media and Communities Professional

Dell Technologies | Enterprise Support Services

#IWork4Dell

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November 9th, 2023 02:57

Monitoring doesn't show broadcast issues, its never a high proportion of traffic.

Receive rate bits/sec.......................... 8264
Receive rate packets/sec....................... 10
Receive percent utilization.................... 0%
Transmit rate bits/sec......................... 51888
Transmit rate packets/sec : ................... 21
Transmit percent utilization................... 0%
Total frames received without errors........... 287069839
Unicast frames received........................ 287064854
Multicast frames received...................... 1298
Broadcast frames received...................... 3687
Total frames received with MAC errors.......... 0
Jabbers received............................... 0
Fragments/Undersize received................... 0
Alignment errors received...................... 0
FCS errors received............................ 0
Overruns received.............................. 0
Total received frames not forwarded............ 1375633196
Total frames transmitted successfully.......... 1442444176
Unicast frames transmitted..................... 1441149667
Multicast frames transmitted................... 386405
Broadcast frames transmitted................... 908104
Transmit frames discarded...................... 172
Total transmit errors.......................... 0
FCS errors transmitted......................... 0
Total transmit frames discarded................ 172
Single collision frames........................ 0
Multiple collision frames...................... 0
Excessive collision frames..................... 0
Time since counters last cleared............... 0 day 21 hr 32 min 15 sec

Moderator

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3K Posts

09-11-2023 05:21 AM

Hi,

 

If you have tried the commands as suggested and still having issues, I recommend contacting the switch support to look at the support logs to identify is any issues with the hardware. 

DELL-Joey C

Social Media and Communities Professional

Dell Technologies | Enterprise Support Services

#IWork4Dell

Did I answer your query? Please click on ‘Mark as Accepted Answer’. ‘Thumbs up’ the posts you like!

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