[c-nsp] New Cisco ME3400 IOS?
Waris Sagheer (waris)
waris at cisco.com
Tue Apr 24 03:25:44 EDT 2012
Excerpt of the doc update in the config guide
<http://www.cisco.com/en/US/docs/switches/metro/me3400e/software/release
/12.2_58_ex/configuration/guide/swqos.html#wp1497063> is as follows:
WTD is configured by using the queue-limit policy-map class command. The
command adjusts the queue size (buffer size) associated with a
particular class of traffic. You specify the threshold as the number of
packets, where each packet is a fixed unit of 256 bytes or as a
percentage value. You can specify different queue sizes in absolute
(number of packets) or percentage terms for different classes of traffic
(CoS, DSCP, precedence, or QoS group) in the same queue. Setting a queue
limit establishes a drop threshold for the associated traffic when
congestion occurs.
You cannot configure the queue size in absolute and percentage terms in
the same policy.
When you configure queue limit, the range for the number of packets is
from 16 to 4272, in multiples of 16, where each packet is a fixed unit
of 256 bytes.
Excerpt of the doc update in the command reference
<http://www.cisco.com/en/US/docs/switches/metro/me3400e/software/release
/12.2_58_ex/command/reference/cli1.html#wp5095786> document is as
follows:
queue-limit
Use the queue-limit policy-map class configuration command to set the
queue maximum threshold for weighted tail drop (WTD) in an output policy
map. Use the no form of this command to return to the default.
queue-limit [cos value | dot1ad dei value | dscp value | precedence
value | qos-group value] {number-of-packets [packets]| percent value}
no queue-limit [cos value | dot1ad dei value | dscp value | precedence
value | qos-group value] number-of-packets [packets] {number-of-packets
[packets]| percent value}
Syntax Description
cos value
(Optional) Set the parameters for each cost of service (CoS) value. The
range is from 0 to 7.
dot1ad dei value
(Optional) Set the parameters for each drop eligibility indicator (DEI)
value. The range is from 0 to 1.
dscp value
(Optional) Set the parameters for each Differentiated Services Code
Point (DSCP) value. The range is from 0 to 63.
precedence value
(Optional) Set the parameters for each IP precedence value. The range is
from 0 to 7.
qos-group value
(Optional) Set the parameters for each quality-of-service (QoS) group
value. The range is from 0 to 99.
number-of-packets [packets]
Set the maximum threshold for WTD as the number of packets in the queue.
The range is from 16 to 4272 and refers to 256-byte packets. The default
is 160 packets. The packets keyword is optional.
Note For optimal network performance, we strongly recommend that you
configure the maximum queue-limit to 272 or less.
percent value
(Optional) Set the maximum threshold for WTD as a percentage of the
total number of packets (buffers) in the common pool.
The range is from 1 to 100.
Defaults
Default queue limit is 160 (256-byte) packets.
Command Modes
Policy-map class configuration
Command History
Release
Modification
12.2(44)EY
This command was introduced.
12.2(55)SE
The dot1ad dei keywords were added.
12.2(58)EX
The percent keyword was added.
Usage Guidelines
...(content)
You cannot configure the queue limit in absolute (number of packets) and
percentage terms in the same policy.
When you use the queue-limit command to configure thresholds within a
class map, the WTD thresholds must be less than or equal to the maximum
threshold of the queue. This means that the queue size configured
without a qualifier must be larger than any of the queue sizes
configured with a qualifier.
When you use the percent keyword to configure the queue limit, note that
the threshold values for WTD qualifiers are calculated based on the
number of packets (buffers) available for each policy or class (the
default for which is 160 packets if you do not configure a queue limit).
The threshold values are not a percentage of the total number of packets
in the common pool on the switch.
Examples
This example shows how to configure WTD as a percentage of packets in
the queue where freeclass1, freeclass2, and freeclass3 get a minimum of
20 percent of the traffic bandwidth. The class-default gets the
remaining 10 percent. In the example:
Part A shows how you can set a percentage queue limit for each class of
traffic.
Part B shows how you can set a percentage queue limit for the threshold.
Part C show how you can configure both in the same policy.
Part A:
Switch(config)#policy-map free-class
Switch(config-pmap)#class freeclass1
Switch(config-pmap-c)#bandwidth percent 20
Switch(config-pmap-c)#queue-limit cos 1 percent 60
Switch(config-pmap-c)#exit
Part B:
Switch(config-pmap)#class freeclass2
Switch(config-pmap-c)#bandwidth percent 20
Switch(config-pmap-c)#queue-limit percent 40
Part C:
Switch(config-pmap)#class freeclass3
Switch(config-pmap-c)#bandwidth percent 20
Switch(config-pmap-c)#queue-limit percent 40
Switch(config-pmap-c)#queue-limit cos 4 percent 10
Switch(config-pmap-c)#exit
Switch(config-pmap)#exit
Related Commands
Command
Description
class
<http://www.cisco.com/en/US/docs/switches/metro/me3400e/software/release
/12.2_58_ex/command/reference/cli1.html#wp1860245>
Defines a traffic classification match criteria for the specified
class-map name.
policy-map
<http://www.cisco.com/en/US/docs/switches/metro/me3400e/software/release
/12.2_58_ex/command/reference/cli1.html#wp1864146>
Creates or modifies a policy map that can be attached to multiple ports
to specify a service policy.
show policy-map
<http://www.cisco.com/en/US/docs/switches/metro/me3400e/software/release
/12.2_58_ex/command/reference/cli2.html#wpxref83492>
Displays QoS policy maps.
-Waris
-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Pavel Skovajsa
Sent: Thursday, April 19, 2012 2:13 PM
To: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] New Cisco ME3400 IOS?
The new 12.2(58)EX is out there, can somebody please share experience
with it?
Also would be great if someone can shed some light on what is actually
considered an 'Enhanced QoS buffer management' since from the release
notes
http://www.cisco.com/en/US/docs/switches/metro/me3400e/software/release/
12.2_58_ex/release/notes/ol24334.html
<http://www.cisco.com/en/US/docs/switches/metro/me3400e/software/release
/12.2_58_ex/release/notes/ol24334.html>
it
seems like the queue size has magically gone up:
////////
Option to configure the queue size threshold in percentage terms. You
can now specify different queue sizes in absolute (number of packets) or
percentage terms for different classes of traffic in the same queue. The
upper limit of the number of packets you can specify when configuring a
queue limit is increased from 544 to 4272.
/////////
Is there a DOC describing how these queue size thresholds actually work
on ME3400?
-pavel
On Fri, Mar 23, 2012 at 11:36 AM, Aled Morris <aledm at qix.co.uk
<mailto:aledm at qix.co.uk> > wrote:
> On 23 March 2012 07:59, Tassos Chatzithomaoglou
> <achatz at forthnetgroup.gr
> >wrote:
>
> > Can you please provide more details about "Enhanced QoS buffer
> management"?
> >
> >
> Sometimes this is marketing speak for "now works (more) like the
> documentation claims it always did" i.e. fixed wiithout admitting that
> the code was broken before.
>
> Aled
> _______________________________________________
> cisco-nsp mailing list cisco-nsp at puck.nether.net
<mailto:cisco-nsp at puck.nether.net>
> https://puck.nether.net/mailman/listinfo/cisco-nsp
<https://puck.nether.net/mailman/listinfo/cisco-nsp>
> archive at http://puck.nether.net/pipermail/cisco-nsp/
<http://puck.nether.net/pipermail/cisco-nsp/>
>
_______________________________________________
cisco-nsp mailing list cisco-nsp at puck.nether.net
<mailto:cisco-nsp at puck.nether.net>
https://puck.nether.net/mailman/listinfo/cisco-nsp
<https://puck.nether.net/mailman/listinfo/cisco-nsp>
archive at http://puck.nether.net/pipermail/cisco-nsp/
<http://puck.nether.net/pipermail/cisco-nsp/>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/cisco-nsp/attachments/20120424/d477df0d/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.png
Type: image/png
Size: 144 bytes
Desc: image001.png
URL: <https://puck.nether.net/pipermail/cisco-nsp/attachments/20120424/d477df0d/attachment-0001.png>
More information about the cisco-nsp
mailing list