QoS in Cisco unmanaged switch

[mblagojevic]

I am looking for information about QoS on the 100 series unmanaged swtches. I am interested in 24-port switches and I have found that such switches provides 4 egress queues with scheduling: "Priority queuing and weighted round-robin (WRR)".

I could not find any details about applied scheduling, e.g., weights in WRR, mapping of CoS to eqress queues, etc.

Can anyone help me to find these information?

[Tom Watts]

Hi Milos,

Here's one document I found, which isn't particularly helpful for your inquiry.

03 Apr 2012 -                                           www.cisco.com/en/US/partner/prod/collateral/switches/ps5718/ps10007/qa_c67-584063.html

Q. How does Auto-QoS work?

A. No configuration is required by the user for Auto-QoS to work in the  Cisco 100 Series Switches. The switch performs the prioritization  automatically. These switches use standard 802.1p class of service (CoS)  settings. They are set with the same QoS settings as the Cisco SPA IP  phones, automatically helping deliver improved voice quality for phones.  Layer 3 QoS (differentiated services code point [DSCP]) is not  affected.

To give a bit more technical answer, the switch has an embedded ability to check the PCP codes for the traffic entering the switch. What this does is give the media contention priority for the uplink when the CoS is greater than normal data traffic. Unfortunately I don't believe there are any actual specifics

Here's other documentation I've found;

http://www.cisco.com/cisco/web/solutions/small_business/products/routers_switches/100_series_switches/index.html

www.cisco.com/en/US/partner/prod/collateral/switches/ps5718/ps10863/at_a_glance_c45-584096.pdf

-Tom
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[Tom Watts]

Milos, here is a screen shot for the unmanage switches. This does answer your question.

Thanks.

-Tom
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[mblagojevic]

Thanks a lot. This is exactly what I was looking for.

From the picture it seems that switch has "Four Internal Hardware Queues" and "Two Priority Queues". What is difference between these queues? Are these Eggress and Ingress queues respectively? I have not seen these in the data sheet.

[Tom Watts]

This information is not in the documentation. 802.1p is the PCP codes. When the PCP code matches the classification for the ingress port, it is placed into the internal queue.  The WRR should be the egress queue.

-Tom
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