5412Zl with Cisco IP phones

[ahmede1]

I have 5412zl switches as L2 access and they are connected to Cisco 6500 siwthes (L3, core/aggreg.). We need to connect Cisco IP phones to the 5412zl switches.

My plan is do this extra config only on the 5412zl switches.

vlan 10 voice

   name "Voice-Vlan"

   tagged user_interface,uplinks

!

According to HP manual , "Labels this VLAN as a Voice VLAN, allowing you to separate, prioritize, and authenticate voice traffic moving through your network"

But does that mean, the voice traffic will be maked as "46 or 5" and the signalling will be marked as "3" when they hit the 6500 or do I need to remark them again.

Is there a way to trust the IP phone marking on the HP switches?

Thanks in advance

[Chrisd131313]

Hi ahmede1,

If you flag a VLAN as a voice VLAN it will automatically set the L2 priority to 6 and RTP to 46 (101110 - EF), I believe that signalling is not included in the voice VLAN option (someone please correct me if they now better) .  But if you want to mark signaling aswell you will need to use DSCP mappings instead of the VLAN voice option...

        vlan <vid> qos dscp-map <codepoint> priority <0-7>

By default signaling has a 802.1p value of 3  and a DSCP value of 24.

011000         24         3           cs3

and EF has a 802.1p value of 7 and a DSCP value of 46.

 101110         46         7           ef

to honor the DSCP values enable diff-services.

        qos type-of-service diff-services

Hope this helps.

[ahmede1]

Thanks for your response..

But I still need the "voice" part for pariotization of the traffic.. Can I mix the two commands? Something like

vlan 10  voice

   name "Voice-Vlan"

   tagged user_interface,uplinks

!

vlan 10 qos dscp-map 101110 priority 5
vlan 10 qos dscp-map 011000 priority 3

qos type-of-service diff-services

Thanks

[Chrisd131313]

Hi ahmede,

My apologies, I made a mistake in the vlan qos line. You can not apply two dscp markings to the same VLAN, you will need to apply the dscp markings globally on the switch.

qos dscp-map <codepoint> priority <0-7>

and then enable the diff-service. That should then do it. You can then still flag the VLAN as voice.

[ahmede1]

Thank you..

I just have a last question. After I configure the Voice VLAN and assign it to the user port (where the IP phone will be connected), if I didn't connect an IP phone and connect a PC directly in the transition period, will the PC work fine? Giving that another un-tagged data vlan is already assigned to the same port. 

[Matcol]

Ahmed, the data VLAN should be untagged and the voice VLAN tagged on each port.

That way, when you attach a PC to any port, it gets onto the DATA VLAN, and if you put a phone, phones should be VLAN-aware (via DHCP maybe?) and use the tagged VOICE VLAN.

[Matcol]

And your DSCP-map looks good - 101 in binary is 5, so 5 is the correct value for DSCP precedence bits set like that.

You really don't need to use QoS to prioritise the signalling.