[c-nsp] ME3400 Output Drops
Pavel Skovajsa
pavel.skovajsa at gmail.com
Fri May 14 04:47:03 EDT 2010
Hello,
All I can say is that this is normal in case of rapid traffic like
video flow. FE ports of ME3400 with default configuration have output
queue
limited to 48 packets. It's not enough for burstable traffic,
especially when the uplink of your ME3400 runs at 1Gb/s. If you don't
need any QoS, just attach a service-policy like:
policy-map max-queue
class class-default
queue-limit 544
If you need QoS the best way is to change the default queue size for
the classes on which you expect to have the largest bandwidth.
Also not sure what is the effect of using "bandwidth" CBWFQ in Egress
QoS on ME3400, I only use shape/policy which IMHO is better suited for
switching hardware. There are too many limitations on these boxes, you
can very easily run into one, so designing proper policy-maps is tough
engineering. Make sure you read the ME3400 QoS config guide:
http://www.cisco.com/en/US/docs/switches/metro/me3400/software/release/12.2_50_se/configuration/guide/swqos.html
There were various discussions about this before - see
http://www.gossamer-threads.com/lists/cisco/nsp/80758 for example.
-pavel
On Fri, May 14, 2010 at 5:43 AM, Rin <rintrum at gmail.com> wrote:
> Hi group,
>
>
>
> We are facing output drops problem on interface f0/2 of ME3400. Our topology
> as below:
>
> Metro-------(G0/1)ME3400(f0/2)-------CPE---------STB----------TV
>
> |________PC
>
>
>
> We try to watch a HD movie on TV and download file on PC at the same time.
> The download rate is at 50Mbps, movie data transfer rate at 10Mbps. Due to
> the output drop, the HD movie quality is not good. The output below shows
> the drop:
>
> C3400# sho int f0/2
>
> FastEthernet0/2 is up, line protocol is up (connected)
>
> Hardware is Fast Ethernet, address is 0026.52a8.4a04 (bia 0026.52a8.4a04)
>
> Description: DUCMINH-modem-test
>
> MTU 1998 bytes, BW 100000 Kbit, DLY 100 usec,
>
> reliability 255/255, txload 119/255, rxload 75/255
>
> Encapsulation ARPA, loopback not set
>
> Keepalive set (10 sec)
>
> Full-duplex, 100Mb/s, link type is auto, media type is 100BaseLX-FE SFP
>
> 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 00:02:25
>
> Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 5034
>
> Queueing strategy: fifo
>
> Output queue: 0/4096 (size/max)
>
> 5 minute input rate 29711000 bits/sec, 3500 packets/sec
>
> 5 minute output rate 46934000 bits/sec, 5307 packets/sec
>
> 881702 packets input, 941885538 bytes, 0 no buffer
>
> Received 8 broadcasts (8 multicasts)
>
> 0 runts, 0 giants, 0 throttles
>
> 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
>
> 0 watchdog, 8 multicast, 0 pause input
>
> 0 input packets with dribble condition detected
>
> 1164876 packets output, 1238627577 bytes, 0 underruns
>
> 0 output errors, 0 collisions, 0 interface resets
>
> 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
>
>
>
> I try to apply egress QoS on interface f0/2 that reserve 23% bandwidth for
> HD movie traffic (COS=4), the HD movie quality is good but there is still
> packet drop for download traffic. Check below output:
>
> C3400#sho policy-map int f0/2
>
> FastEthernet0/2
>
>
>
> Service-policy output: EGRESS_QOS
>
>
>
> Class-map: COS45 (match-any)
>
> 237435 packets
>
> Match: cos 4 5
>
> Bandwidth percent 23 (23000000 bps)
>
> Output Queue:
>
> Max queue-limit default threshold: 160
>
> Tail Packets Drop: 0
>
>
>
> Class-map: class-default (match-any)
>
> 972306 packets
>
> Match: any
>
> Output Queue:
>
> Max queue-limit default threshold: 160
>
> Tail Packets Drop: 5266
>
> Bandwidth percent 77 (77000000 bps)
>
> Output Queue:
>
> Max queue-limit default threshold: 160
>
> Tail Packets Drop: 5266
>
>
>
> I try to change the queue size for default class to maximum value 544. The
> output drops reduce but there's still drop.
>
> C3400(config)#do sho policy-map int f0/2
>
> FastEthernet0/2
>
>
>
> Service-policy output: EGRESS_QOS
>
>
>
> Class-map: COS45 (match-any)
>
> 219146 packets
>
> Match: cos 4 5
>
> Bandwidth percent 23 (23000000 bps)
>
> Output Queue:
>
> Max queue-limit default threshold: 160
>
> Tail Packets Drop: 0
>
>
>
> Class-map: class-default (match-any)
>
> 882062 packets
>
> Match: any
>
> Tail Packets Drop: 181
>
> Bandwidth percent 77 (77000000 bps)
>
> Queue Limit
>
> queue-limit 544 (packets)
>
> Output Queue:
>
> Max queue-limit default threshold: 544
>
> Tail Packets Drop: 181
>
>
>
> My question is why ME3400 drop packet even the data rate is much less than
> the interface capability (60Mbps/100Mbps). Anyone has other solution for
> this issue?
>
> Below is the show version output
>
> C3400#sho ver
>
> Cisco IOS Software, ME340x Software (ME340x-METROIPACCESSK9-M), Version
> 12.2(50)SE1, RELEASE SOFTWARE (fc2)
>
> Copyright (c) 1986-2009 by Cisco Systems, Inc.
>
> Compiled Mon 06-Apr-09 10:05 by amvarma
>
> Image text-base: 0x00003000, data-base: 0x01C00000
>
>
>
> ROM: Bootstrap program is ME340x boot loader
>
> BOOTLDR: ME340x Boot Loader (ME340x-HBOOT-M) Version 12.2(40r)SE1, RELEASE
> SOFTWARE (fc1)
>
>
>
> C3400 uptime is 3 hours, 46 minutes
>
> System returned to ROM by power-on
>
> System image file is "flash:me340x-metroipaccessk9-mz.122-50.SE1.bin"
>
>
>
>
>
> This product contains cryptographic features and is subject to United
>
> States and local country laws governing import, export, transfer and
>
> use. Delivery of Cisco cryptographic products does not imply
>
> third-party authority to import, export, distribute or use encryption.
>
> Importers, exporters, distributors and users are responsible for
>
> compliance with U.S. and local country laws. By using this product you
>
> agree to comply with applicable laws and regulations. If you are unable
>
> to comply with U.S. and local laws, return this product immediately.
>
>
>
> A summary of U.S. laws governing Cisco cryptographic products may be found
> at:
>
> http://www.cisco.com/wwl/export/crypto/tool/stqrg.html
>
>
>
> If you require further assistance please contact us by sending email to
>
> export at cisco.com.
>
>
>
> cisco ME-3400-24FS-A (PowerPC405) processor (revision C0) with
> 118784K/12280K bytes of memory.
>
> Processor board ID XXXXXXXX
>
> Last reset from power-on
>
> 3 Virtual Ethernet interfaces
>
> 24 FastEthernet interfaces
>
> 2 Gigabit Ethernet interfaces
>
> The password-recovery mechanism is enabled.
>
>
>
> 512K bytes of flash-simulated non-volatile configuration memory.
>
> Base ethernet MAC Address : 00:26:52:A8:4A:00
>
> Motherboard assembly number : 73-11063-09
>
> Power supply part number : 341-0203-01
>
> Motherboard serial number : XXXXXXXXX
>
> Power supply serial number : XXXXXXXXX
>
> Model revision number : C0
>
> Motherboard revision number : A0
>
> Model number : ME-3400-24FS-A
>
> System serial number : XXXXXXXX
>
> Top Assembly Part Number : 800-28864-01
>
> Top Assembly Revision Number : G0
>
> Version ID : V01
>
> CLEI Code Number : XXXXXXXX
>
> Hardware Board Revision Number : 0x04
>
>
>
>
>
> Switch Ports Model SW Version SW Image
>
>
> ------ ----- ----- ---------- ----------
>
>
> * 1 26 ME-3400-24FS-A 12.2(50)SE1
> ME340x-METROIPACCESSK9-M
>
>
>
>
>
> Configuration register is 0xF
>
>
>
> Sorry for the long email. Thanks,
>
>
>
> Rin
>
>
>
>
>
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