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How to limit a vNic to use 5GB/s speed. I can't find the right QOS policy to assign to a vNic

Should limit a vNic to use maximum of 5GB/s..

1 Accepted Solution

Accepted Solutions

You don't really specify the line rate. Line-rate is the speed which will cause entrie available BW to be used.

To answer the underlying question, when you lower the rate, you specify shaping value and burst.

Shaping is discussed for example here:

http://www.cisco.com/en/US/tech/tk543/tk545/technologies_q_and_a_item09186a00800cdfab.shtml#policing

Example

bdsol-6248-06-A(nxos)# show run | section Gold

policy-map type queuing org-root/ep-qos-Gold_QoS

  class type queuing class-default

    bandwidth percent 100

    shape 5000000 kbps 65000

and when using line rate.

bdsol-6248-06-A(nxos)# show run | section Platinium

policy-map type queuing org-root/ep-qos-Platinium_5124

  class type queuing class-default

    bandwidth percent 100

    shape 10000000 kbps 5124

Related output from my USC in the lab.

View solution in original post

4 Replies 4

Marcin Latosiewicz
Cisco Employee
Cisco Employee

Rate field

The expected average rate of traffic. Traffic that falls under this rate will always conform. The default is line-rate, which equals a value of 0 and specifies no rate limiting. The minimum value is 8, and the maximum value is 40,000,000.

The granularity for rate limiting on a Cisco UCS M81KR Virtual Interface Cardadapter is 1Mbps. These adapters treat the requested rate as a "not-to-exceed" rate. Therefore, a value of 4.5Mbps is interpreted as 4Mbps. Any requested rate of more than 0 and less than 1Mbps is interpreted as 1Mbps, which is the lowest supported hardware rate limit.

Rate limiting is supported only on vNICs on the Cisco UCS VIC-1240 Virtual Interface Card and Cisco UCS VIC-1280 Virtual Interface Card. The Cisco UCS M81KR Virtual Interface Card supports rate limiting on both vNICs and vHBAs.

http://www.cisco.com/image/gif/paws/110509/ucs-qos-04.gif

source:

http://www.cisco.com/en/US/products/ps10278/products_configuration_example09186a0080ae54ca.shtml

and

http://www.cisco.com/en/US/docs/unified_computing/ucs/sw/gui/config/guide/2.1/b_UCSM_GUI_Configuration_Guide_2_1_chapter_010100.html

Thank you, Marcin.

Quick question -

Once you set the line rate as 5GB/s, would that be a hard limit on that PCIe device? or can the device get more than the specified bandwidth?

You don't really specify the line rate. Line-rate is the speed which will cause entrie available BW to be used.

To answer the underlying question, when you lower the rate, you specify shaping value and burst.

Shaping is discussed for example here:

http://www.cisco.com/en/US/tech/tk543/tk545/technologies_q_and_a_item09186a00800cdfab.shtml#policing

Example

bdsol-6248-06-A(nxos)# show run | section Gold

policy-map type queuing org-root/ep-qos-Gold_QoS

  class type queuing class-default

    bandwidth percent 100

    shape 5000000 kbps 65000

and when using line rate.

bdsol-6248-06-A(nxos)# show run | section Platinium

policy-map type queuing org-root/ep-qos-Platinium_5124

  class type queuing class-default

    bandwidth percent 100

    shape 10000000 kbps 5124

Related output from my USC in the lab.

Thank you, Marcin.

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