Voice Over IP Intro

VoIP Introduction

• Originally separate infrastructure
• VoIP is overlay on top of data services
  • A wire that basically handles both things

• Audio is digitized by a codec
  • Analog to digital conversions
    • Something your sound card does
• Traffic classification
  • If you see real time audio you can enable policies to speed it out or slow it down for example
• Traffic marking
  • When we set things like the Type of Service (ToS) or the Class of Service (CoS)
  • To set priorities between services
• Traffic prioritization
  • We use it to leverage queuing, have some packets go before these other packets
  • Which data gets served first.

VoIP Components

• When we want to take the VoIP traffic we may encounter with the Voice Router
  • Routers are smart enough to monitor for quality over the internet
• It's too hard to deliver a consistent audio stream
• Call Center
  • Cisco call manager
• Voice gateway
  • May be able to handle PSTN stuff
  • ISDN interface
  • Deadends on device

VoIP Considerations

• Service Level Agreement
  • Application will perform at a given level
  • Is a promise.
• Cost of downtown
  • Maybe it is important to have backup solutions
• Location services
• 911
  • We need our 911 services in place
  • If 911 services are not functioning you can fall in a law suit
• Network Performance
• Quality of Service (QoS)
  • Maintain a particular level of quality for our service.
• Traffic Policing
  • You can specify how fast certain applications perform on the network
  • Figure out who are my top talkers then you can create policies to balance traffic