SPA 500 Phones and ESW Switches QOS Best Practice

Unanswered Question
Jul 15th, 2010

Hello all,

I have a quick question about QOS on SPA phones and ESW switches and what the best practice is.  Do the SPA phones mark their packets at both layer 2 and layer 3?  If they do, what markings do they use?  COS 5 for layer 2 and EF for layer 3?  When setting up QOS on an ESW switch, is it best to leave it at the default advanced mode?  Or is it better to set QOS on the switch to basic and set it to trust either cos or dscp?

Thanks in advance,


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Alberto Montilla Thu, 07/22/2010 - 06:04

Dear Sir;

SPA phones in fact marks packets/frames at both L3 and L2, this is to handle different QoS schemes without any configuration change requirement.

Together with the ESW switches, the QoS settings are plug and play. ESW and SPA set two VLANs, one for Voice (100) and one for data/default traffic. QoS is handled at L2, with the VLAN ID + the 802.1p bits. This is plug and play by using the Cisco Discovery Protocol, available in both products.

The phones use a different setting for signaling and voice packets as recommended. Settings below:

SIP traffic (signaling): CoS 3, ToS 0x68

RTP traffic (voice): CoS 6, ToS 0xb8

Again, for ESWs with SPA phones, dont touch anything ;-), default settings works perfect for best QoS.



techiegzz Fri, 07/23/2010 - 07:04

Seeing that the ESW switches currently either have gigabit ethernet or PoE and not both, how does this all work with the SGE and SFE series gigabit switches such as the SGE2010P? Does it require configuration or default like the ESW switches?

David Harper Fri, 07/23/2010 - 20:44

The ESW family have gigabit PoE options in 8 and 24 port form factors - the model numbers are ESW-540-8P-K9 and ESW-540-24P-K9 respectively.  You can configure an SFE or SGE switch with close to equivilent functionality, but it is a very manual process.  Is there a specific reason for using the other switch types, or were you unaware of the gig/PoE options in the ESW family?



techiegzz Fri, 07/23/2010 - 20:48

I wanted a switch with both PoE and gigabit and the ESW does not have both in one switch. The ESW series either has PoE or gigabit and not both features in a single switch. I guess I have no choice but to go with the ESW with the 10/100 PoE.

Steven DiStefano Fri, 07/23/2010 - 21:07

I have an ESW with 8 ports GIgE and POE. Have you explored all models?

Look at ESW-540 models, where you will find more port densities w PoE

and Gig.

Steve DiStefano

Technology Solutions Architect - Sales

Cisco Systems

Research Triangle Park

North Carolina, U.S.A


On Jul 23, 2010, at 11:48 PM, "techiegzz"

Steven DiStefano Sat, 07/24/2010 - 06:38

Sorry there is no POE on ESW-540-48 but does have GigE, but we do have

POE on ESW-540-24P and GigE there too, so 24 port option too.

The 48 port ESW is a funny mix, you are right in that it doest follow

the 8. and 24 port models with both Poe and GigE.

Steve DiStefano

Technology Solutions Architect - Sales

Cisco Systems

Research Triangle Park

North Carolina, U.S.A


On Jul 24, 2010, at 5:23 AM, "techiegzz"

David Harper Fri, 07/23/2010 - 23:17

I think you misunderstood me.  The two part numbers I quoted are ESW switches that are gigabit on all ports, and have power o

ver ethernet support on all ports.  They should be exactly what you are looking for.



techiegzz Sat, 07/24/2010 - 02:29

@David Harper

I clearly understood you, I just don't see how that works for my scenario since I need two 48-port switches with both gigabit and PoE for a total of 96 ports with both features as opposed to one switch with PoE and another with gigabit. With such an arrangement as you suggested I will need two ESW 48-port with PoE and two with 48-port gigabit just to achieve a combined 96 combined PoE and gigabit RJ45 ports.

OEMS are known for such products so that you have to go buy higher grade and more expensive models to achieve more of your ideal scenario, same thing happens with excluding layer 3 capabilities.


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