Convert QOS from Cisco to Extreme.

[Jim_Keeffe]

Hi - we're converting some Cisco 6509s to your BD8810 switches and I need to know how to set up QOS in EXOS, mainly on the uplinks where congestion may occur. On the Cisco switch, I use 'mls qos' and tweek the output queues a little bit, then I configure 'mls qos trust dscp' on the access and uplink ports to trust the dscp markings. (The IP phones and PBX mark the traffic with the appropriate DSCP values and we just want to trust them)

I only have four QOS classes as follows:

voice = 46, EF
video = 32, CS4
signaling = 24, CS3
default = 0

I understand how to tag the voice and data vlans on the uplinks ports, but I'd appreciate it if you would let me know how to configure QOS to trust the DSCP markings and place traffic in the appropriate queues.

Thanks.

[Jim_Keeffe]

Hi Paul - Thanks for the info above.

Here's what I've come up with so far from your info and reading an Avaya/Extreme QOS document. In this case I want to put both video conferencing and voice in the same queue. (Same as I do on Cisco - the same priority queue as Cisco recommends. Sounds strange but it works just fine.)

create qosprofile qp7
create qosprofile qp4
disable dot1p examination ports all
enable diffserv examination ports all
config diffserve examination code-point 46 qp7
config diffserve examination code-point 32 qp7
config diffserve examination code-point 24 qp4

That's it so far. Do you see anything I'm missing or doing wrong?

- Jim

[treese]

I've testing this config in the our lab and enabled diffserv examination on all ports on the edge switches and cores. The VOIP servers reside on the cores. In production would you only enable diffserv examination on all ports with voice vlans and voip server vlan or keep the config "enable diffserv examination ports all"? Lot of ports on our cores doing different things. Thank you

[treese]

I've testing this config in the our lab and enabled diffserv examination on all ports on the edge switches and cores. The VOIP servers reside on the cores. In production would you only enable diffserv examination on all ports with voice vlans and voip server vlan or keep the config "enable diffserv examination ports all"? Lot of ports on our cores doing different things. Thank you


Try this again - In production would you only enable diffserv examination on ports with voice vlans and voip server vlan only or keep the config "enable diffserv examination ports all"? Lot of ports on our cores doing different things. Thank you

[Paul_Russo]

Hey Jeff

In order for the switch to honor the DSCP we have to do a few things on the switch but before I explain that let me give a little detail to how QoS works on the switch. There is a precedence to how QoS is looked at in the switch. ACLs have the highest then .1p then port-based, then VLAN and finally DSCP. In addition .1p examination is enabled by default. This means that if a packet has 802.1p and DSCP we will look at .1p before we look at DSCP.

If you want to look at DSCP then I recommend either disabling .1p and enabling DSCP or using an ACL policy to look at the DSCP to map the traffic.

In order to look at traffic we have to do a number of things. 1) create the QoS profile for example create qosp qp4. 2) config the diffserv Code-Point and add it to the QP for example config diffserv examination code-point 46 qp4 3) enable diffserv examination on the ports for example enable diffserv examination ports
all all
port list

As I mentioned above if you go with DSCP examination then disable .1p or map the .1p value to the same queue for example config dot1p type 6 qp4.

Let me know if that helps or if you need me to give more information.

Thanks
P