We have a client who recently updated an accounting application, after the update they have perceived slowness in the application, therefore the provider recommended that they apply QoS for this service.
I would like to know how this configuration could be done, which requires having QoS for the accounting application.
The client has a core catalyst 4500 where the server of the accounting application is connected and also the switch where the user who uses the application connects.
Before investing the time to complete the required QoS configuration, it would be worthwhile in validating the accounting software vendors recommendation.
Firstly consider monitoring the link connected to the application server during the moments of slowness. This will enable you to determine if link saturation is being observed. You may discover that the root cause is the server resource, instead of the network itself. A good tool for this is Paessler PRTG Network Monitor. They may offer you a free trial, which would be suffice for you to conduct your analysis.
Finally, is the accounting application optimised for LAN usage? Some accounting packages are very heavy, and are better delivered via remote desktop / emulation (Microsoft Remote Desktop/App or Citrix XenApp)
Without knowing the exact setup, it would be difficult to actually give you a configuration you could implement.
Generally you define class-maps to identify and classify traffic and define policy-maps that act on these classifications to alter the traffic priority and bandwidth utilization.
But "class-map", "policy-map", and "service-policy" are going to be the keywords you want to research.
Provide more information and help can continue.
Also, accounting packages tend to be written very lousy when it comes to network communication.
I've seen similar upgrades bork the network stack on a server and require the network interface on the server to be reinstalled to get things normal again. Virus scanners on the server or client could be slowing things down. The upgrade may have pushed the runtime requirements beyond what the old client and/or server is capable of....Lot's of reasons could be at play and MORE likely than NOT, that software provider is not going to admit any issues with their software. So do not be surprised if their "helpful" suggestions are simply noise to hopefully make you go away.