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QOS configutration for Mitel VOIP

PEI_1
Advisor

QOS configutration for Mitel VOIP

Our company has decided to implement VOIP to all regional offices. Each region will be installed with Mitel IP phones and a Mitel MXe box to the existing LAN network. The WAN network which connects all the regions is maintained by our service provider. We only have control to the LAN switches.

I need some advises on QOS and DSCP for VoIP. We use Procurve 2610 switches in LAN except the edge switch, Catalyst 3750 which connects to WAN via Fiber.

We will use our Server 2008 as DHCP for the IP phones. For DHCP option, the settings:
DCSP 46 Priority 6
VLAN Voice priority 6
TFTP : Mitel MXe

There will be data and voice vlans. All ports on VLAN voice will be tagged. Data vlans as untagged ports.

I am thinking when an IP phone receives the DHCP options, the voice packets will be tagged with the DSCP and VLAN priority settings as above.

Q: Would these packets retain the Qos and DSCP information travelling all the way from the IP phone to the LAN Switches, L3 Catalyst switch, the WAN, then to the destination IP phone?

Q: If the packets would retain these information, do I still need to set the priority for VLAN voice on LAN Switches and the edge switch Catalyst 3750?


Q: Should I have single connection between the LAN switch (Procurve) and edge switch (Catalyst)or separate connections for each vlan (voice and data)?

Please refer to attached picture explain the existing (as is) and proposed (to be) network.

Thanks.

2 REPLIES
Pieter 't Hart
Honored Contributor

Re: QOS configutration for Mitel VOIP

Q1 : Within each "branch" you can configure "trust" for packets allready marked with DSCP value.
Than packes will keep their DSCP/priority setting within the branch network.
Across the WAN probably not.
Ask your WAN-provider, mostly they do QOS on a less granular way (COS instead of DSCP).

Q2 : Assigning the DSCP value through DHCP is not enough.
You have to configure the switches to actually "use" the DSCP value, so packets are treated differently.

Q3: You can connect the procurve with the Cisco with a single link (tagged vs vlan-trunk)
or do the same with multiple links (port-trunk vs etherchannel)
PEI_1
Advisor

Re: QOS configutration for Mitel VOIP

Thanks Pieter.

on Procurve 2610, I can set the vlan to voice:
sw1(config)#vlan 10
sw1(vlan 10)#voice

Q:What does the voice setting on vlan 10 has effect to the incoming/outgoing voice packets?

Q:If the packet has DSCP 46, do I have to assign priority value to it? i read that DSCP 46 is default to priority 7. Then my only job is to turn on DSCP classifier as below:

#qos type-of-service diff-services
Please let me know i am right on this.


Q:For incoming/outgoing voice ports, what Qos options should i use. 802.1P priority or DSCP policies with 802.1p priority?

Q: If the packet is tagged with priority 7 (from DHCP option), it will be sent to high priority buffer queue of outgoing port. No additional Qos configuration is required.

If this priority 7 is retained over the WAN and arrives remote branch with priority 7, why do we need DSCP?