[c-nsp] 2960s output drops

Sat Apr 14 02:31:07 EDT 2012

If it is cat 3560x/3750x, do we need to tune the buffer as well?

Regards,
Alexander Halim

On Apr 5, 2012, at 11:08 PM, <Vinny_Abello at Dell.com> wrote:

> I don't know about this specifically, but if it's true I know I had to manually tune the buffers on some 3560's just to make them bearable. I'm in the process of migrating away from them onto a 6500 with WS-X6748-GE-TX's instead. For what it's worth, this was how I tuned the 3560's to drastically reduce (but nowhere near eliminate) the output drops due to the tiny buffers:
> 
> mls qos srr-queue output cos-map queue 2 threshold 3 0 1 2 3 4 5 6 7
> mls qos srr-queue output dscp-map queue 2 threshold 3 0 1 2 3 4 5 6 7
> mls qos srr-queue output dscp-map queue 2 threshold 3 8 9 10 11 12 13 14 15
> mls qos srr-queue output dscp-map queue 2 threshold 3 16 17 18 19 20 21 22 23
> mls qos srr-queue output dscp-map queue 2 threshold 3 24 25 26 27 28 29 30 31
> mls qos srr-queue output dscp-map queue 2 threshold 3 32 33 34 35 36 37 38 39
> mls qos srr-queue output dscp-map queue 2 threshold 3 40 41 42 43 44 45 46 47
> mls qos srr-queue output dscp-map queue 2 threshold 3 48 49 50 51 52 53 54 55
> mls qos srr-queue output dscp-map queue 2 threshold 3 56 57 58 59 60 61 62 63
> mls qos queue-set output 1 threshold 2 400 400 100 400
> mls qos queue-set output 1 buffers 0 100 0 0
> mls qos
> 
> Props go to some blog I found this on. Hope it helps someone who might be struggling with output drops on this type of platform.
> 
> -Vinny
> 
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Nikolay Shopik
> Sent: Thursday, April 05, 2012 3:48 AM
> To: Tom Sands
> Cc: Piotr Wojciechowski; cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] 2960s output drops
> 
> I hear that 2960S and 3560X have almost similar buffers, do you know
> something about this?
> 
> On 04/04/12 23:11, Tom Sands wrote:
>> Beware that the 2960S incurred a drastic reduction in packet buffers compared to prior the initial 2960 product line (cut the port buffers in half).
>> 
>> ________________________________________
>> From: cisco-nsp-bounces at puck.nether.net [cisco-nsp-bounces at puck.nether.net] on behalf of Nikolay Shopik [shopik at inblock.ru]
>> Sent: Wednesday, April 04, 2012 1:54 PM
>> To: Piotr Wojciechowski
>> Cc: cisco-nsp at puck.nether.net
>> Subject: Re: [c-nsp] 2960s output drops
>> 
>> Hardware is Gigabit Ethernet, address is 2c3f.386c.850c (bia 2c3f.386c.850c)
>>  Description: trestcom
>>  MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,
>>     reliability 255/255, txload 1/255, 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 00:00:01, output never, output hang never
>>  Last clearing of "show interface" counters 02:41:55
>>  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 2197
>>  Queueing strategy: fifo
>>  Output queue: 0/40 (size/max)
>>  5 minute input rate 222000 bits/sec, 139 packets/sec
>>  5 minute output rate 779000 bits/sec, 159 packets/sec
>>     1001165 packets input, 123531512 bytes, 0 no buffer
>>     Received 30810 broadcasts (16248 multicasts)
>>     0 runts, 0 giants, 0 throttles
>>     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
>>     0 watchdog, 16248 multicast, 0 pause input
>>     0 input packets with dribble condition detected
>>     1428427 packets output, 830613125 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
>> 
>> 
>> On 04.04.2012 21:58, Piotr Wojciechowski wrote:
>>> On 4/4/12 18:35 , Nikolay Shopik wrote:
>>>> Hi,
>>>> 
>>>> So we just replaced some aging c3524XL with 2960S and suddenly start
>>>> seeing output drops on one of port facing client, while 3524 never had
>>>> output drops to this client.
>>>> 
>>>> Traffic levels pretty much low like 1-2mbit with 200-300pps levels. I
>>>> believe this is because uplink now 1Gbit, but previously it was just
>>>> 100mbit and client port also 100mbit.
>>>> 
>>>> But just wanna confirm with you guys should I ignore these drops or do
>>>> something about.
>>> 
>>> What kind of drops are those? Can you provide us show interface output?
>>> 
>>> Regards,
>>> 
>>> 
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