9200L switch drops - Page 2

Moudar · ‎11-13-2023

Hi,

I got some 9200L switches with some drops, some people are complaining about Teams meatings are bad, when i checked the switch i could find these drops. Maybe these drops do not have a big effect on the overall switching process, but I wonder why do these happen.

I checked this guide:

https://www.cisco.com/c/en/us/support/docs/switches/catalyst-9300-switch/216236-troubleshoot-output-drops-on-catalyst-90.html

I tried to do as the guide says but still have drops:

sh interfaces | in Total output drops:
  Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 0
  Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 0
  Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 0
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 758
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 644
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 1224
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 1944
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 295
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 868
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 144
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 5030
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 1670
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 385
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 950
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 2383
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 392
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 2353
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 1570
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 798
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 1304
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 89
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0

My configuration looks like this:

policy-map QOS_Q_OUT
 class VOICE
  priority level 1 percent 10
  queue-buffers ratio 5
 class class-default
  bandwidth remaining percent 100
  queue-buffers ratio 55

!
interface GigabitEthernet1/0/3
 switchport access vlan 419
 switchport mode access
 ip flow monitor FLOW-MON input
 spanning-tree portfast
 service-policy output QOS_Q_OUT
!
All interfaces have the same confiuration!!

Any ideas on how to improve my configuration to have less drops.

It is weird to have thses drops but not showing these when trying this command:

show platform hardware fed switch active qos queue stats interface gi 1/0/4

show platform hardware fed switch active qos queue stats interface gigabitEthernet 1/0/4
----------------------------------------------------------------------------------------------
AQM Global counters
GlobalHardLimit: 2875   |   GlobalHardBufCount: 0
GlobalSoftLimit: 10437   |   GlobalSoftBufCount: 0

----------------------------------------------------------------------------------------------
High Watermark Soft Buffers:  Port Monitor Disabled
----------------------------------------------------------------------------------------------
Asic:0 Core:0 DATA Port:7 Hardware Enqueue Counters
-------------------------------------------------------------------------
 Q Buffers          Enqueue-TH0          Enqueue-TH1          Enqueue-TH2
   (Count)              (Bytes)              (Bytes)              (Bytes)
-- ------- -------------------- -------------------- --------------------
 0       0                    0                    0               203139
 1       0                    0                    0            278708956
 2       0                    0                    0                    0
 3       0                    0                    0                    0
 4       0                    0                    0                    0
 5       0                    0                    0                    0
 6       0                    0                    0                    0
 7       0                    0                    0                    0
Asic:0 Core:0 DATA Port:7 Hardware Drop Counters
-----------------------------------------------------------------------------------------------------------
 Q             Drop-TH0             Drop-TH1             Drop-TH2             SBufDrop              QebDrop
                (Bytes)              (Bytes)              (Bytes)              (Bytes)              (Bytes)
-- -------------------- -------------------- -------------------- -------------------- --------------------
 0                    0                    0                    0                    0                    0
 1                    0                    0                    0                    0                    0
 2                    0                    0                    0                    0                    0
 3                    0                    0                    0                    0                    0
 4                    0                    0                    0                    0                    0
 5                    0                    0                    0                    0                    0
 6                    0                    0                    0                    0                    0
 7                    0                    0                    0                    0                    0

sh inter gigabitEthernet 1/0/4
GigabitEthernet1/0/4 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 8c84.4248.6804 (bia 8c84.4248.6804)
  MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, media type is 10/100/1000BaseTX
  input flow-control is on, output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:05:32, output 00:00:01, output hang never
  Last clearing of "show interface" counters 8w6d
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 1224
  Queueing strategy: Class-based queueing
  Output queue: 0/40 (size/max)
  5 minute input rate 8000 bits/sec, 1 packets/sec
  5 minute output rate 17000 bits/sec, 7 packets/sec
     62003445 packets input, 56167278049 bytes, 0 no buffer
     Received 72901 broadcasts (64715 multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 64715 multicast, 0 pause input
     0 input packets with dribble condition detected
     83141837 packets output, 67288428361 bytes, 0 underruns
     Output 579517 broadcasts (2391039 multicasts)
     0 output errors, 0 collisions, 0 interface resets
     1136 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

Do my configuration do some job?! Why ?

Any ideas

Moudar · ‎11-13-2023

I don't use QoS for Teams specificly, but voice is best as you can see!

policy-map QOS_Q_OUT
 class VOICE
  priority level 1 percent 10
  queue-buffers ratio 5
 class class-default
  bandwidth remaining percent 100
  queue-buffers ratio 55

Joseph W. Doherty · ‎11-13-2023

Yes, I saw that.

Effectively you have PQ for "VOICE", whatever you're matching for that class and just one other queue for everything else. Not a very expansive QoS policy.

BTW, just reading an MS article using QoS for Teams (https://learn.microsoft.com/en-us/microsoftteams/qos-in-teams). What especially caught my attention was accessing off LAN MS Teams servers.

Moudar · ‎11-13-2023

From that guide:
"Congestion occurs when the destination interface has a number of packets that exceed its output rate."
Does this mean that if the trunk port (1GB) does not keep up with all other access ports, that time, dropping begins?

MHM Cisco World · ‎11-14-2023

Did you ever try my suggestion?

Moudar · ‎11-14-2023

Now, I am running the Cisco defaults you sent. This will need some time to test. What I needed in my question before is only to understand!

MHM Cisco World · ‎11-14-2023

Hope it works

Wishing you a good luck

Joseph W. Doherty · ‎11-14-2023

@Moudar wrote:

From that guide:
"Congestion occurs when the destination interface has a number of packets that exceed its output rate."
Does this mean that if the trunk port (1GB) does not keep up with all other access ports, that time, dropping begins?

Possibly.

Initially, such congestion will begin to fill egress queue(s). When the capacity of egress queue(s) is exceeded, then you'll see drops.

However, for particularly sensitive traffic, like voice and/or video, their packets sitting waiting in a queue can be adverse to them too. I.e. voice/video application issues without drops. To mitigate this, QoS might be used to prioritize voice/video traffic.