QOS on UC540 eth ports?

[ambleside]

Have a customer with a small UC540 system. 4 users in the office, all with SPA525G2's.  All have Mac's on their desk connected to the PC port on the 525's, all phone ethernet lands directly on the UC540.  Also attached to the UC540 ethernet is a mac time capsule.

Every hour, time machine runs an incremental backup and if they are on the phone, call quality suffers.  The smart-port macro's for cisco-phone don't appear to assign a COS to the voice vlan nor can I find any 1Q settings on the ethernet side.

The bandwidth reservation means that the outbound is just fine - they just can't hear the callers.

I opened case # 616822475 for this but it seems like both me and tech support must be missing something.

Technically, I could throw in an ESW-540-8P - it allows QOS tagging for the VLANs - but that seems a little drastic....Meanwhile the customer is faced with no backups or broken calls.

[mcasimirc63]

You are correct.  You will need to purchase an additional switch to allow QOS markings.  The UC500 does not have the functionality to allow you to extend the trust boundary to the IP Phone and or perform QOS functions at the access layer for endpoint devices.

When you get the switch all you would need to do is set the IP Phone as a conditionally trusted device.  Once that's done the switch and the IP phone exchange CDP information. The phone will then mark (or rewrite if needed) its VOIP (RTP) traffic with COS 5 and signaling packets (RTCP) with COS 3.  The conditional option works well because the switch will not honor any QOS marking unless an IP phone is connected.

[ambleside]

What protocol needs to be enabled to enable this autodiscovery?  Or does it only work with CCA and ESW switches? I'm going to throw something in there this AM but it won't be an ESW...If I set the up as the phones as trunk ports will that do it? Or should they be general ports?

[JOHN NIKOLATOS]

is the Time capsule wireless?  Are you using the UC500 wireless to transfer the backups?  If it is I am curious what VLAN it is connected to the data or vocie vlan...

[ambleside]

Time capsule is wired. Wireless doesn't cause any conflict - moved them off wired to make this work for the weekend for the client.

[mcasimirc63]

The ESW will place DSCP marked traffic into a queue.  If you select the "strict priority" queue it will place a delay free guarantee for that traffic no matter what the percentage.  The rest of the traffic can go into the weighted round robin queue.  Similar to LLQ but not exactly the same.  The standard practice is to put DSCP 24 (CoS 3) into queue 2 and DSCP 46 (CoS 5) into queue 4.   DSCP 46 is used to the actual voice packets (RTP) and 24 is used for control/statistics (RTCP).

You should set the queues as follows

Queue 1   10%  Data – Best effort

Queue 2   20% RTCP

Queue 3   70% Routing protocols / IP Routing

Queue 4   1% Strict priority – RTP