QoS: Don’t VoIP without it!

Jeff SzczepanskiFounder and CTO

Allworx Corpjrs@allworx.com

Agenda

• QoS Philosophy• Relativity• How Good is Good?• Pitfalls of VoIP• QoS Management• Conclusions

QoS Philosophy

• QoS = Quality of Service• Defining Quality• Quality is a relative concept.

…but Quality Relative to what!?

QoS Relativity

• The “relativity” part here implies a comparison or a continuum of quality

…and a continuum of quality implies invoking a process to maintain or improve such quality.

QoS is a Process

• Think about QoS like you think about quality on a manufacturing line

Achieving good QoS is more about the processes you deploy than it is about the products, features, or technologies involved.

How Good is Good?

• The Manufacturing analogy is Six Sigma• IT Planning, Server and Data Network folks talk

about and strive to a goal of “Five 9’s” of reliability.

• But is 99.999% Good? Expectations in telephony is very high.

…Understand that in traditional telephony, reaching “Five 9’s” is still a bad day at the office.

Traditional Telephony

TDM is really simple, if the wires are connected, it is probably going to work.

Data Networks

…especially without QoS processes

Pitfalls of VoIP

• Echo• One-Way Audio• Packet Loss• Speech Artifacts• 911 Call Location Management• Intermittent Problem Isolation• General System Complexity

VoIP Traffic

VoIP is the ‘Canary in the Coal Mine’ of your data network.

Why VoIP?

• Increased channel densities• Lower Network Costs• Single Shared Infrastructure with Data• Presence Integration• Unified Messaging• New Service Offerings

Moral of StoryIt is easy to under estimate the task of building

and maintaining a robust VoIP network…

TDM QoS VoIP QoS….is a bit more relative

vs.

Deploying VoIP

• Managed Switches• Dedicated VLAN for Voice Traffic• Traffic Prioritizing Routers• Guaranteed Bandwidth -> SLA’s• Redundant Uplinks and Equipment

– Avoid single point of failure

• Plan for 911 location Requirements

Managing VoIP

Call Logging and Traffic Monitoring

is key…

…especially for isolating apparently intermittent problems. Change Logs and Version Control very helpful too.

Conclusions• VoIP has many advantages but relative to QoS it is

certainly not without its pitfalls.• It’s still new and while no longer bleeding edge it is still

relatively early on the overall curve.• A QoS plan is critical to doing Enterprise VoIP successfully• Good QoS only results with:

– Staffing IT with VoIP Knowledgable People– Deploying the right kind of Equipment– Configuring Systems Properly– Tracking Changes and Logging Performance– Closing the process loops on all of the above

Q&A

Thanks!