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bdearlove

65 Posts

10940

January 17th, 2006 15:00

QOS Based on VLAN, Unable to Set

Good Day,
 
I am in the process of implementing a Nortel VOIP solution over my 40 or so Dell Switches.
 
Reading the documentation, I need to set a higher priority for my voice VLAN. On the 3348's that I have with a Voice VLAN configured I go to Interface Cos/Qos Settings to set a higher priority, but cannot choose the VLAN as shown in the documentation. Is this a version issue? I seem to be at the correct version, or am I doing something incorrectly. Any help would be appreciated!
 

Unit No.

 Software Version Boot Version Hardware Version
Unit 1              1.2.0.6              1.0.0.13                  00.00.03
Unit 2              1.2.0.6              1.0.0.13                  00.00.03

bdearlove

65 Posts

January 18th, 2006 20:00

Hey All!
 
Anyone know what could be happening here?
 
Thanks!

DELL-GregG

812 Posts

January 19th, 2006 10:00

The User's Guide was provided by the vendor and was based on a pre-release firmware. I do not believe any of the shipping versions of the firmware supported setting default CoS values based on the VLAN.

bdearlove

65 Posts

January 19th, 2006 13:00

Bugger, that isn't good.
 
Our vendor(Nortel) does not support DSCP. Their documentation reccommends placing their VLAN on a higher priority. Is this possible to do with 3348's, 6024's and 5324's?
 
We are looking at purchasing another 10 or so Dell switches but I will be holding off until I can figure this out. Should I contact Dell directly?
 
Thanks for the help.

DELL-GregG

812 Posts

January 19th, 2006 15:00

None of the switches support setting the default CoS value based on the VLAN. The default CoS value can only be configured on a port or LAG.

However, this setting simply tells the switch what CoS value to use for UNTAGGED traffic entering the port. Most VOIP devices that do not support DSCP use the VPT value in the 802.1p priority tag. Voice traffic is sent tagged with the CoS value and data traffic is sent untagged. In this scenario, you would simply need to configure the switch to trust the CoS value and map that value to a higher priority queue.

bdearlove

65 Posts

January 19th, 2006 18:00

Good Day,
 
Thanks for your Quick response. According to Nortel, their device only supports SVP, not 802.1p or DSCP.
They mention that you can tag the port that the Voice server is on with higher priority. Is that possible?
Here is what I think I do:
1. Enable Trust Mode, set DSCP on all switches.
2. At interface, choose the port, set default COS incoming traffic to set to 7

Here is a excerpt from the documentation.
End-to-end QoS, such as DiffServ, and Layer 2 QoS, such as 802.1 Q/p, are
not supported on the wireless telephone system. Any UNIStim commands
sent to the wireless handsets attempting to adjust Layer 2 or Layer 3 QoS
parameters are ignored. In addition, the WLAN IP Telephony Manager 2245
does not support any Layer 2 or Layer 3 QoS mechanisms.

However, it is possible to provide QoS mechanisms through configuration of
network equipment.
The Layer 2 switch port to which the WLAN IP Telephony Manager 2245 is
connected can be configured to add 802.1 Q/p tagging. The Layer 3 port that
acts as the gateway for the WLAN IP Telephony Manager 2245 can be
configured to add the appropriate DiffServ tagging. Since all of the signaling
and media traffic passes through the WLAN IP Telephony Manager 2245, all
packets are tagged with the appropriate priority. If more than one WLAN IP
Telephony Manager 2245 is used, each Layer 2 port to which a WLAN IP
Telephony Manager 2245 is connected must be configured to add the
802.1 Q/p tagging.
 
Thanks for all your help!

DELL-Randy

132 Posts

January 30th, 2006 21:00

The documentation indicates the WLAN IP Telephony unit does not support the QoS mechanisms, however these services may be provided by the networking devices in the topology.
 
Essentially the networking equipment may use QoS mechanisms to differentiate the VoIP traffic from the data traffic and then mark the VoIP traffic with a higher priority via Layer 2 (802.1p) or Layer 3 (DSCP) methods.
 
The PowerConnect 6024 (Layer 3 switch) is the only PowerConnect switch capable of differentiating and marking traffic with a specific priority; this feature is unavailable on the Layer 2 PowerConnect product line. 
 

bdearlove

65 Posts

January 30th, 2006 22:00

Hi Randy,

Sounds good, the Cisco Ap's can take the Voice traffic with a COS value and the desktop phones can take voice with a COS value also, so as long as I let my 3348's trust the ports we should be good to go.

Thanks for the help!

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