HP 5800 and QoS

[L1nklight]

I am getting ready to undertake a voice project and I am going to need to configure QoS across the board. I haven't really been able to find any detailed information about how other users have done it and I was wondering if any one had any good links or references for QoS on Comware/5800 based switches and integrating with a Cisco voice system. I've read though the ACL and QoS documentation available from HP and it looks like I should go with an IntServ based model but I am unsure of any real differences between IntServ and DiffServ besides the fact that DiffServ does not signal the network to reserve resources prior to sending data. The manual mostly deals with DiffServ. 

What do you guys use? IntServ or DiffServ?

[Vince-Whirlwind]

The amount of effort you put into implementing QoS should be proportional to the scale of the problem.

For QoS on a LAN, hopefully there are no over-subscribed bottlenecks to deal with, so QoS rarely comes into play. Therefore you should go with whatever requires minimal effort.

For the WAN, QoS becomes much more necessary, but you depend on the WAN service provider for that - all you have to do is ensure each packet is correctly classified and then shape your traffic on egress to the WAN provider, ensuring the markings on the outgoing traffic match the provider's scheme.

intServ is more for complicated multimedia applcations anyway - diffServ is good for voice packets.

[L1nklight]

Thanks for the good information. So my current architecture is as follows:

• Datacenter A (primary) housing all connections to the LEC
• Datacenter B (secondary) housing alternative connections to the LEC
• Central Office where users and phones are located

All three facilities are based on HP 5800 series switches and all 3 sites are connected directly to each other over a layer 2 WAN link. The carrier has ensured us that QoS is supported on the link. Based on what you advised (very sage like by the way, I appreciate it) it sounds  like the recommendation anecdotally is to only apply QoS on the long distance WAN links. Does this imply that I only need to apply a QoS policy to that related interface?

[Vince-Whirlwind]

You'll have 3 aims for your QoS policy:

1/ traffic is correctly classified as, eg,  Voice/Video/Priority Apps/Default

2/ the QoS markings (DSCP) match exactly what the provider is expecting. For example, I'm looking at one right now where the WAN provider offers 4 classes of service to my customer. I normally would configure Voice to use DSCP EF(46) and Video to use AF41(34), BUT, in this case the WAN provider has both EF and AF41 assigned to the "Gold" class, so I'm going to have to re-classify the Video to something like AF31 so that when it hits the WAN, it will get put in the "Silver" class and won't be competing with the Voice for bandwidth. In turn, this means I have to reclassify everything else currently with a DSCP value between 16-30 to 0 so that the WAN provider will treat it as "Bronze".

3/ You shape the traffic as it exits your devices to go to the WAN so that you are only feeding the amount of bandwidth that your WAN service specifies. The shaping uses the defined traffic classes to ensure that your shaping does not kill any Voice traffic, and only drops Video traffic if there is no lower priority traffic to drop instead.

I'm not saying don't apply QoS internally, I'm just saying it almost certainly won't be necessary, so don't spend too much effort on it - go with a simple internal QoS - the sort of thing that automatically sets itself up when you define the Voice VLANs as "voice" for example.

[L1nklight]

I was looking for documentation on what exactly happens on HP A5800s when you designate a voice VLAN. I have a lot of experience with Cisco and their Call Manager Express system as well as Unity Express on their 2800 and 2900 series routers and integrated switch platforms, but I am unsure if the same behavior as tagging a voice VLAN on Comware applys. Do you happen to know which of the technical manuals goes through that? 

I have gone through the following documents from HP already:

• ACL and QoS (5998-1618 software release 1211, old documentation I know)
• Command References for ACL and QoS
• Command References for Layer 2

[Vince-Whirlwind]

I use the

HP 5920 & 5900 Switch Series
ACL and QoS
Configuration Guide

(There is one of these for each model).