Is QoS possible in non-routed environment

[aoshea]

Dear Netpro,

I have two sites that are separate by a laser link (100Mbps). There is currently a stack of 3 x 3548XL's and two 3550 EMI's (3550-48 port 3550-12g) and at the main site. All switches are connected via fibre to the 3550-12g and have redundant giga-stack connections for failover in the stack.

The remote site has now expanded and has a 3548XL and 3550-48 port EMI switches.

They were original configured just as a single (non-trunked) connection across the laser link. But since expansion we now have more people and have a requirement for QoS between the sites.

We have also purchased another laser connection (doubling bandwidth to 200Mbps).

Now to the question ...

Is there anyway to implement QoS across the link (or trunk/s if required) with out having to re-address the network (it is currently just one subnet 192.168.1.x /24)

Basically QoS will need to be configured between two avaya call managers, I know where these plug in, the codex they are using and also the hex code for dscp (not sure on this the avaya engineer has mentioned it may be needed).

Your help is appreciated.

Regards, Adrian.

[rais]

QoS is available at Layer-2. The tag field in 802.1Q frame contains three bits for Class of Service (CoS). Catalyst 3550s support QoS using CoS bits.

Hope this helps.

[rwcrowe]

As posted you can implement QoS via Layer 2 CoS but there is one thing you need to consider here. The Gigastack is a shared bus, so configuring QoS is not going to help you much. You might want to look at re-evaluating your physical setup and having point-to-point Gig links between the access switches and the distribution switch.

[aoshea]

sorry for the confusion, I used the term stack to describe the wiring closet. All switches are connected through multimode fibre in a point to point connection with the core switch (3550-12g), the giga-stacking modules are mearly to provide redundancy if the fibre connection fails.

Thanks again for highlighting this. Regards, Adrian.

[aoshea]

Thanks for your help here, is there any url's that may be of benefit to me.

Thanks again. Adrian,

[rais]

One helpful URL is:

http://www.cisco.com/en/US/tech/tk389/tk813/technologies_tech_note09186a00801558cb.shtml

Thanks.