is there a possibillity to change a vlan into a voice vlan?
We didn't create a special voice vlan for the new IP-Phones we ordered and now we are running into quality problems on the phones when somebody is talking and copying something on the network..
If we are not able to change the vlan, would it be enough to create a QoS Policy?
imho, QoS is for routing priority, VLAN separates ethernet segment into broadcast domains (for example, prevent someone with itunes running on a laptop which is continually scanning for itunes shares from hosing your phone calls)
QOS is much more than routing priority - on switches its inbound and outbound queuing, shaping, policing, remarking, etc...
Apply the following configuration on all your ports on the switch and let me know how that helps. Trafic marked as DSCP40 to 46 will be using queue 5 and get strict priority over all other queues. We use GTS to limit the SP queue to 10Mbps to ensure an incident with marked trafic does not kill the rest of your trafic. That CIR is enough for access or uplinks on a given 48 ports, but you would obviously want to adjust it higher if you have a thousand users behind a given interface.
If you can confirm that your telephony solution marks its RTP voice payload with DSCP 40 up to 46 (it should be the later), this configuration will quite happily prioritize voice as your requirements.
---- CCIE 24349, MASE 2011 Networking Canadian HPN Partner of the Year
