RE: LLQ

Hi Scott,

Thanks for your contribution. I stand corrected on the amount a router can
send.

I failed to notice the input and output stats on the directly connected
switch even if the packets were shown as dropped on the source router.

Per your observation and guidance and I checked the switch.

SW-1#sh int f0/5 | i rate

  Queueing strategy: fifo

  30 second input rate 5870000 bits/sec, 485 packets/sec

  30 second output rate 5864000 bits/sec, 484 packets/sec

With that said, I still want to see the 'policy-map interface' output from
Ron and see if the packets were dropped because of the police command or
just dynamips.

Regards,

Edison Ortiz

Routing and Switching, CCIE # 17943

  _____

From: Scott M Vermillion [mailto:scott_at_it-ag.com]
Sent: Tuesday, December 08, 2009 4:51 PM
To: Edison Ortiz
Cc: Cisco certification
Subject: Re: LLQ

Hi Ed,

I've done this many times on both routers and switches - the 6500 story was
just a little anecdote to keep things interesting and to tie what I was
saying back to some real-world circumstance. Also, this isn't so much about
>forwarding< as it is about >sourcing<. So the bigger/more powerful the
CPU, the more Mbps of IMCP Echo Requests you are likely to be able to
generate. But even with the little guys, you can do fairly well (especially
if, as I mentioned beforehand, you specify a large ICMP Echo Request size
along with timeout zero).

Yes, you see periods in your below output because you aren't awaiting any
reply (and thus no "!" will be possible). This does not indicate that the
sourcing router dropped its own ICMP traffic outbound. Rather, it just
means it didn't get an Echo Reply in a span of zero milliseconds. If you
repeat that test and watch your interface counters every couple of seconds,
you'll see what I mean.

And my Dynamips comment was directed more towards what Ron was attempting
(he mentioned using Dynamips for his QoS testing, which I was just
cautioning against).

Cheers,

Scott

On Dec 8, 2009, at 2:35 , Edison Ortiz wrote:

Hi Scott,

First

You can't compare the forwarding rate on a switch vs a router.

Second,

Timeout 0 will dropped all packets on a router's ping:

R0#ping 150.1.15.1 size 1500 repeat 100000 time 0

Type escape sequence to abort.

Sending 100000, 1500-byte ICMP Echos to 150.1.15.1, timeout is 0 seconds:

......................................................................

......................................................................

......................................................................

...................................................................

Third,

I used real hardware on my test (masking my serial number just in case..)

R0#sh diag

Slot 0:

        C2651XM 2FE Mainboard Port adapter, 4 ports

        Port adapter is analyzed

        Port adapter insertion time 4w5d ago

        EEPROM contents at hardware discovery:

        Hardware Revision : 4.1

        PCB Serial Number : xxxxxxxxxxxx

        Version Identifier :

        Product (FRU) Number :

        Chassis Serial Number : xxxxxxxxxxx

        Part Number : 73-7756-06

        RMA History : 00

        RMA Number : 0-0-0-0

        Board Revision : B0

        Deviation Number : 0-0

        EEPROM format version 4

        EEPROM contents (hex):

          0x00: 04 FF 40 03 6F 41 04 01 C1 0B 46 4F 43 30 39 30

          0x10: 38 34 4B 4C 43 89 FF FF FF FF CB 12 FF FF FF FF

          0x20: FF FF FF FF FF FF FF FF FF FF FF FF FF FF C2 0B

          0x30: 46 54 58 30 39 32 30 41 31 39 42 82 49 1E 4C 06

          0x40: 04 00 81 00 00 00 00 42 42 30 80 00 00 00 00 FF

          0x50: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF

          0x60: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF

          0x70: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF

        WIC Slot 0:

        Serial 1T WAN daughter card

        Hardware revision 1.0 Board revision J0

        Serial number xxxxxxxxx Part number 800-01514-01

        FRU Part Number WIC-1T=

        Test history 0x0 RMA number 00-00-00

        Connector type Wan Module

        EEPROM format version 1

        EEPROM contents (hex):

          0x20: 01 02 01 00 01 5E 68 18 50 05 EA 01 00 00 00 00

          0x30: 98 00 00 00 00 09 11 01 FF FF FF FF FF FF FF FF

        WIC Slot 1:

        Serial 1T WAN daughter card

        Hardware revision 1.0 Board revision J0

        Serial number xxxxxxxx Part number 800-01514-01

        FRU Part Number WIC-1T=

        Test history 0x0 RMA number 00-00-00

        Connector type Wan Module

        EEPROM format version 1

        EEPROM contents (hex):

          0x20: 01 02 01 00 01 5D FB 79 50 05 EA 01 00 00 00 00

          0x30: 98 00 00 00 00 09 10 01 FF FF FF FF FF FF FF FF

Edison Ortiz

Routing and Switching, CCIE # 17943

-----Original Message-----
From: Scott M Vermillion [mailto:scott_ccie_list_at_it-ag.com]
Sent: Tuesday, December 08, 2009 4:19 PM
To: Edison Ortiz
Cc: 'ron wilkerson'; 'Cisco certification'
Subject: Re: LLQ

Hey Ed,

Depending on the platform, you can generate several Mbps of traffic

with ICMP Echo. You simply need to specify the timeout as zero so

that there is no wait for a reply. It helps to specify a large echo

request size as well. The only time I ever saw a 6500 CPU spike to

and remain near 100% was when I used this technique to remotely

troubleshoot a throughput problem (the 6500 being the only "host" on

the network over which I had any control from afar).

Having said that, this is one area where Dynamips falls flat on its

face; I wouldn't trust any results involving Dynamips and any QoS

function, as there is no physical interface into which and out of

which to clock traffic. Dynamips is OK for practicing the

configuration of QoS, but not for capturing any meaningful results of

said configuration.

Regards,

Scott

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Received on Tue Dec 08 2009 - 16:57:56 ART