06-09-2015 07:58 AM - edited 03-08-2019 12:28 AM
Some colleagues notified me that RDP connection they are using hiccups. Windows draw after a second and so on.
Those colleagues are in a branch office connected to a 2960s that is also connected to a 2960 located in headquarter office via dedicated link, using TRUNK.
Both uplink trunk switches are forced to 100Mb full duplex because of layer1 appliance of the provider.
Investigating a bit using "sh controllers ethernet-controller" turns out that uplink trunk interfaces of both switches report a lot of "Too large frames".
MTU size of 2960 is 1500.
QoS is disabled.
CPU seems ok (40/60)
Can you please help me to diagnose and fix this behavior ?
Thanks for help.
06-09-2015 08:01 AM
Please share
sh int <>
sh int <> counters errors
Thanks,
Madhu
06-09-2015 08:03 AM
Are both sides MTU 1500?
06-09-2015 08:12 AM
Both 2960 are MTU 1500.
Don't know the SDH layer 1 MTU size appliance though.
06-09-2015 10:30 AM
Is the output drops increasing continually? Configure Load interval on the interface to 30 sec so that we can have a much better view of how much traffic traversing over it.
06-09-2015 10:32 AM
Also is it possible to increase the MTU on both sides just to check if that solves this problem?
Thanks,
Madhu
06-09-2015 10:35 AM
Since it is 2960 you have to apply system mtu jumbo globally and requires a reload.
Thanks,
Madhu
06-10-2015 12:24 AM
Will enabling jumbo mtu disrupt something ?
Is it a safe fix ?
Thanks !!!
06-10-2015 12:23 AM
Hi,
is it load-interval 3 30 ? or load-interval 1 30 ?
06-09-2015 08:08 AM
This is the HQ uplink interface:
switch48-04#sh interfaces gigabitEthernet 1/0/43 GigabitEthernet1/0/43 is up, line protocol is up (connected) Hardware is Gigabit Ethernet, address is b4e9.b099.352b (bia b4e9.b099.352b) Description: TRUNK MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec, reliability 255/255, txload 5/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Full-duplex, 100Mb/s, media type is 10/100/1000BaseTX input flow-control is off, output flow-control is unsupported ARP type: ARPA, ARP Timeout 04:00:00 Last input never, output 00:00:00, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 22653480 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 388000 bits/sec, 303 packets/sec 5 minute output rate 1977000 bits/sec, 660 packets/sec 415966026 packets input, 149124634477 bytes, 0 no buffer Received 7321375 broadcasts (5696260 multicasts) 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 5696260 multicast, 0 pause input 0 input packets with dribble condition detected 1018735876 packets output, 604726049775 bytes, 0 underruns 0 output errors, 0 collisions, 1 interface resets 0 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 Port Align-Err FCS-Err Xmit-Err Rcv-Err UnderSize OutDiscards Gi1/0/43 0 0 0 0 0 22653480 Port Single-Col Multi-Col Late-Col Excess-Col Carri-Sen Runts Giants Gi1/0/43 0 0 0 0 0 0 0
And this is the branch office uplink interface:
switch48-07#sh int gigabitEthernet 1/0/48 GigabitEthernet1/0/48 is up, line protocol is up (connected) Hardware is Gigabit Ethernet, address is ece1.a9ae.08b0 (bia ece1.a9ae.08b0) Description: TRUNK MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec, reliability 255/255, txload 1/255, rxload 7/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Full-duplex, 100Mb/s, media type is 10/100/1000BaseTX input flow-control is off, output flow-control is unsupported ARP type: ARPA, ARP Timeout 04:00:00 Last input never, output 00:00:00, output hang never Last clearing of "show interface" counters 00:54:35 Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 3132000 bits/sec, 1204 packets/sec 5 minute output rate 426000 bits/sec, 353 packets/sec 1874124 packets input, 866594668 bytes, 0 no buffer Received 264680 broadcasts (229880 multicasts) 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 229880 multicast, 0 pause input 0 input packets with dribble condition detected 1115200 packets output, 189351650 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 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 Port Align-Err FCS-Err Xmit-Err Rcv-Err UnderSize OutDiscards Gi1/0/48 0 0 0 0 0 0 Port Single-Col Multi-Col Late-Col Excess-Col Carri-Sen Runts Giants Gi1/0/48 0 0 0 0 0 0 0
Please note that reset counter on Gi1/0/48 interface to see errors increase.
06-09-2015 08:12 AM
The interface 1/0/43 shows lot of output drops.
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 22653480
Can you please check the interface utilization graph to see you are not oversubscribing it.
Thanks,
Madhu
06-09-2015 08:13 AM
That interface is the uplink trunk to other office.
Where can I check the utilization graph and hwo to understand if oversubscribing it ?
06-09-2015 08:21 AM
I browsed switch via http and did this shot. Frames seem too big.
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