Few Questions

[aali]

Do I need to setup QOS for Voice Traffice in HP Procurve 5400 and 3800 switches.   I understand that the ports for Voice are tagged members and that takes care of QOS, and the data is untagged.  Just wondering if sthat will suffice for QOS or If I still needed to specify, then that setting is applied to the untagged voice ports.

What is HP Equivalent to Cisco "Show interface trunk" command to see what is being trunked.

Thanks

[LorenzoCastro]

Hello, whether that will suffice or not really depends on the specific network requirements of the customer. You are correct in saying that if the port is tagged it will include Dot1p information which can then be used to achieve QoS. The dot1p levels map to priority levels which are mapped to queues, which have outbound scheduling priorities that can also be modified.  Higher priority traffic would go into higher queues.  If you have untagged voice ports then those will not behave the same as the tagged ports because they will not carry dot1p info.  There are several ways you can make sure untagged voice traffic gets a certain priority though.  Mark the specific untagged VoIP ports with port priority; give the Voice VLAN itself a specific priority mapping, mark the vlan itself as a voice vlan.  If the environment required it and needed more granularity you can classify traffic and apply service policies to your interfaces.  The other thing you’ll want to take into consideration is using DSCP marking to classify the traffic as close to the edge as possible as well as preserve the markings over layer 3 links.   

In regards to the show trunk interface command, I do not believe there is an equivalent command in the HP OS.  You would have to do the show vlan # and check the specific port for tagged membership in each vlan.   The show interface trunk command allows you to see any trunked ports, the encapsulation and the allowed vlans on the trunk.  I guess if you have a lot of VLANs to sift through this command would be helpful.  

[Brad_199]

LorenzoCastro,

There seems to be various different ways of implementing QoS and I have never really understood if there is a common rule of thumb or best practise that means one method of QoS would be better than the other (& so on....)

Could you expand further to what you've already mentioned to help understand it better?

[LorenzoCastro]

Hey Brad,  I'm no QoS expert, so I won't try and expound on the various aspects of QoS.  There are volumes written on it.  I would suggest checking out some Cisco press QoS books for a good reference.  Safari is a great resource for this.   The ASE Network Infrastructure study guide and QoS guides in the documentation sets of procurve E and HP A series switches have some great info for understanding and implementing.  As far as QoS for your environment you really need to know how traffic flows, potential choke points in your network, capabilities and behavior of your sensitive traffic, etc.  For example, if you have a VoIP system, it probably marks traffic at a certain priority.  That needs to be understood and then compared to where that fits in on your switch.  For example, based off of traffic types and requirements you may only need 4 queues instead of the default 8.  If you change these you will probably want to to customize GMB on these queues as well.  You may want to mark your VoIP traffic with higher priority by applying a DSCP value directly on your Voice VLAN and then assigning that value a higher priority queue assignment (you would usually give it EF).   If you have a delay sensitive application that uses a certain port you can assign priority based off of the apps TCP port number, ip address, Ethernet interface number, etc. You can also get very granular and classify traffic and based off it's classification assign, reassign, and or mark different CoS values using either dot1p or DSCP markings, which then ties into your egress queues mentioned above.  Anyway, I think checking out the resources above is probably your best bet to get an understanding of the various methods.