Question

You are required to design a VoIP application. Discuss the requirements for such an application in terms of its protocols and performance requirements. What types of protocols you would need to design a complete VoIP application (Hint: real time streaming protocols and signaling protocols, etc.)? [5 Marks]

2. Discuss the architecture of messanging app in terms of its protocols. Address and discuss all the essential protocols used by messaging app for communication.

Answer 1

Requirements for VOIP

There are three types of requirements which is needed for VOIP which is software requirements, hardware requirements and protocol requirements.

1. Software requirements : which includes

* PCM interface

• * Voice processing module
• * Idle noise detector
• * Tone detection
• * Voice processing module
• * Echo cancellation
• * Network management protocol

2. Hardware requirements: It includes

• * PC (personal computer)
• * IP telephones
• * Gateway (allows data to flow from one network to another)
• * IP based networks
• * Voice cards (hardware interface which stimulates a FXS on a router or network switch)

3. Protocol requirements:

• * Real time transport protocol (network protocol to deliver audio over IP networks)
• * Resource reservation protocol (real time system for an efficient quality band transmission to receiver. It is usually used by receiver side for the fast delivery of transmission packets from the sender to the receiver)
• * G.711 (It is a narrowband audio codec, it passes audio signals in the range of 300Hz to3400 Hz and samples these audio signals at a rate of 8000 samples per second, with the tolerance rate of 50 parts per million. It gives best audio quality for VOIP.)
• * G.723.1 (It is a  speech codec. It is used in VOIP due to it's low bandwidth requirement.)
• * H.323 ( It is not a single protocol but rather an entire group of protocols. There are somany individual single protocol under this protocol. Users can communicate through internet and make use of different products that are H.323 standard compatible. It bridges multimedia communications between packet based and swtch circuit networks(SCN))

- Commonly using VOIP protocols are Session Initiation Protocol(SIP), Media gateway control protocol(MGCP), Skinny client control protocol(SCCP) and H.323.

- The performance matrics of VOIP includes packet jitter(It is also be called as packet delay variation(PDV). A network with constant delay has no packet jitter), packet latency(which is delay. It is the time taken from source sending packet to destination), Post dial delay and echo, and the metrics including network packet loss.