[c-nsp] low throughput of 10GbE line

Mack McBride mack.mcbride at viawest.com
Mon Mar 15 17:38:22 EDT 2010


Those aggregates are wrong.
The port groups are arranged fairly oddly.

(fabric asic)
#show int Te7/1 capabilities | inc ASIC
  Ports-in-ASIC (Sub-port ASIC) : 1,4-5,7 (1)
#show int Te7/2 capabilities | inc ASIC
  Ports-in-ASIC (Sub-port ASIC) : 2-3,6,8 (2)

(FPGA pairs)
((1,4),(5,7)),((2,3),(6,8))

The inner pairs are 16Gbits.
The quadruples are 20Gbits.
It is easy to subscribe these blades incorrectly since the port
order is not what one would expect.

The transceiver having issues does indeed appear to be overheating.
That can cause all kinds of issues.

LR Mack McBride

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Nick Hilliard
Sent: Monday, March 15, 2010 3:17 PM
To: Jirí Procházka
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] low throughput of 10GbE line

On 15/03/2010 16:26, Jirí Procházka wrote:
> When traffic on this link reaches aproximately 6Gbps, latence to servers
> gets rapidly worse (about 100-150ms, about 2ms before)

the 6708 card has 200 megs of buffers per port.  doing the sums, this works
out at about 160ms of latency, assuming you're seeing a 10Gb microburst.
So at a superficial level, it looks like you're seeing packet drops because
of full buffers.

Also, you're running the card in oversubscription mode.  How much traffic
is te4/7 pushing?  I'd hazard a guess that you're running into
over-subscription problems on the blade.

I can't find the more detailed guide to the 6708 architecture on the cisco
web site, but there's a brief overview here:

> http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps708/prod_white_paper0900aecd80673385.html#wp9000681

while it's not going to give you exact details on tiny microbursts, I'd
consider installing RTG or YRTG with a 30 second poll interval, and monitor
all the ports on blade 4, along with the following aggregates.

te4/1 + te4/2
te4/3 + te4/4
te4/5 + te4/6
te4/7 + te4/8

te4/1 + te4/2 + te4/3 + te4/4
te4/5 + te4/6 + te4/7 + te4/8

Do you have a second 6708 blade?  You may need to consider running these
ports in non-oversubscribed mode.

Nick

 and speed is
> unpredictably slowing. Servers are able to generate much more than
> 10Gbps. I have tried to assign IP from this VLAN directly to
> vlan-interface at 3750 and latence is bad as well.
> 
> 
> The two problems which I can see at 7606 are following:
> 
> 1) Input queue drops at the interface. They appear at the same time as
> the high latence. I tried to set lower hold-queue, but no difference.
> Any type of qos or other bandwidht limiting methods are applied.
> 
> sitel-edge-new#show int te4/8
> TenGigabitEthernet4/8 is up, line protocol is up (connected)
>  Hardware is C7600 10Gb 802.3, address is 001e.f7f7.bd5f (bia
> 001e.f7f7.bd5f)
>  Description: SITEL-TTC-New10GbE
>  MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec,
>     reliability 255/255, txload 3/255, rxload 126/255
>  Encapsulation ARPA, loopback not set
>  Keepalive set (10 sec)
>  Full-duplex, 10Gb/s
>  Transport mode LAN (10GBASE-R, 10.3125Gb/s)
>  input flow-control is off, output flow-control is off
>  ARP type: ARPA, ARP Timeout 04:00:00
>  Last input 00:00:07, output 00:00:41, output hang never
>  Last clearing of "show interface" counters 18:56:25
>  Input queue: 0/4096/96151289/0 (size/max/drops/flushes); Total output
> drops: 0
>  Queueing strategy: fifo
>  Output queue: 0/4096 (size/max)
>  30 second input rate 4942942000 bits/sec, 410813 packets/sec
>  30 second output rate 143433000 bits/sec, 241176 packets/sec
>     34434311308 packets input, 51018973201607 bytes, 0 no buffer
>     Received 21472 broadcasts (17607 multicasts)
>     0 runts, 0 giants, 0 throttles
>     0 input errors, 0 CRC, 0 frame, 96151289 overrun, 0 ignored
>     0 watchdog, 0 multicast, 0 pause input
>     0 input packets with dribble condition detected
>     19623750753 packets output, 3094225873410 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
> 
> 
> the second side of line looks ok
> 
> TTC-3750-MAIN#show int te2/0/2
> TenGigabitEthernet2/0/2 is up, line protocol is up (connected)
>  Hardware is Ten Gigabit Ethernet, address is 001e.7a4f.fb9e (bia
> 001e.7a4f.fb9e)
>  Description: TTC-SITEL-New10GbE
>  MTU 1600 bytes, BW 10000000 Kbit, DLY 10 usec,
>     reliability 255/255, txload 129/255, rxload 3/255
>  Encapsulation ARPA, loopback not set
>  Keepalive not set
>  Full-duplex, 10Gb/s, link type is auto, media type is 10GBase-SR
>  Media-type configured as  connector
>  input flow-control is off, output flow-control is unsupported
>  ARP type: ARPA, ARP Timeout 04:00:00
>  Last input 00:00:51, output 00:00:16, output hang never
>  Last clearing of "show interface" counters 01:36:19
>  Input queue: 0/4096/0/0 (size/max/drops/flushes); Total output drops: 0
>  Queueing strategy: fifo
>  Output queue: 0/4096 (size/max)
>  30 second input rate 149330000 bits/sec, 249506 packets/sec
>  30 second output rate 5062720000 bits/sec, 420886 packets/sec
>     1400794396 packets input, 104446053346 bytes, 0 no buffer
>     Received 0 broadcasts (1250 multicasts)
>     0 runts, 0 giants, 0 throttles
>     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
>     0 watchdog, 1250 multicast, 0 pause input
>     0 input packets with dribble condition detected
>     2427526833 packets output, 3649915537744 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
> 
> 
> 
> 
> 2) It looks that concerned transciever is a little bit overheated..but I
> don't trust these sensors much..
> 
> sitel-edge-new#show interfaces transceiver
> Transceiver monitoring is disabled for all interfaces.
> 
>                                           Optical   Optical
>           Temperature  Voltage  Current   Tx Power  Rx Power
> Port       (Celsius)    (Volts)  (mA)      (dBm)     (dBm)
> ---------  -----------  -------  --------  --------  --------
> Te4/1        39.3       0.00      36.8      -2.8      -1.0
> Te4/2        34.6       0.00      43.1      -2.6      -3.3
> Te4/3        36.8       0.00      29.7      -2.5      -1.0
> Te4/4        35.3       0.00       5.9      -1.9      -1.7
> Te4/5        44.1       0.00      45.4      -2.0      -7.7
> Te4/6        40.0       0.00      36.0      -3.4      -2.2
> Te4/7        40.8       0.00      34.0      -3.3      -0.5 +
> Te4/8        71.9 +     0.00       6.0      -3.2      -3.4
> 
> 
> 
> 
> some more debug info:
> 
> 7606 ->
> 
> sitel-edge-new#show platform hardware capacity fabric
> Switch Fabric Resources
>  Bus utilization: current: 35%, peak was 47% at 19:53:03 CET Thu Mar 11
> 2010
>  Fabric utilization:     Ingress                    Egress
>    Module  Chanl  Speed  rate  peak                 rate  peak
>    1       0        20G   14%   21% @18:26 11Mar10   19%   31% @18:20
> 12Mar10
>    2       0        20G   25%   39% @17:50 11Mar10    2%   10% @02:07
> 12Mar10
>    2       1        20G   10%   26% @19:41 11Mar10   33%   49% @18:06
> 11Mar10
>    4       0        20G   25%   63% @13:00 14Mar10    5%   20% @18:15
> 11Mar10
>    4       1        20G   45%   79% @18:07 11Mar10   50%   73% @09:43
> 13Mar10
>    5       0        20G    2%    5% @14:22 12Mar10   12%   19% @19:08
> 11Mar10
>  Switching mode: Module                                        Switching
> mode
>                  1 truncated
>                  2 truncated
>                  4 compact
>                  5                                               flow
> through
> 
> 
> 
> 
> I'm going to replace the "overheated" transciever in 7606 this night and
> hope it's the solution..but don't trust it much.
> 
> 
> Any advice would be really appreciated!
> 
> 
> Best regards,
> 
> 
> Jiri Prochazka
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