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Tuesday, March 27, 2012

Delay,Packet loss,Jitter & Echo


 Delay – Delay is a measure of time delay experienced in a system. The precise definition of which depends on the system and the time being measured. The delay of a network specifies how long it takes for a bit of data to travel across the network from one node to another.

Packet loss - Packet loss means when one or more packets traveling across a computer network to particular destination it is fail to reach their. Every data packet has a life time to when it is traveling on a network. If it is expired due to traffic congestion the packet will be loss.

Jitter - Jitter is the variation in the delay of received packets. If we sent data packets evenly spaced intervals, but due to traffic congestion, improper queuing or configuration errors packets may come at unequal intervals.

Echo – Echo means when a person is specking with a phone he will hear the same voice through earpiece with the delay.

NGN (Next Generation Network )


NGN the Next Generation Network will be the future of all telecommunication. Tease technologies which are categorized as Networks can integrate and handle networks of different technologies. It is a packet-based network which can provide services including telecommunication Services. For example it can handle a land line network, a data network, a VOIP network and even a CDMA network at once. It can provide every current services and service switch are expected to be provided in future at single platform. NGNs are commonly built around the Internet Protocol, and therefore the term "all-IP" is also sometimes used to describe the transformation toward NGN. NGNs offer significant cost savings to operators and new services to consumers, but there are also challenges in maintaining the quality, reliability and security of communications.

NGN has 4 layers. they are,
  • Service management
  • Network control
  • Core switching
  • Edge access

NGN Supports for a wide range of service applications and mechanisms based on service building blocks (including real-time/streaming/non-real-time services and multi-media). When we consider internet access people want speed data access therefore NGN can handle Broadband capabilities with end-to-end QoS and transparency.

NGNs combine a number of different networks, so a new approach to assign numbers or addresses in the network may be desirable. In particular, numbers could be assigned to individual users, rather than to devices. Ofcom has also proposed that the transition to NGNs offers an opportunity to make number portability (retaining your number when you change provider) more efficient. In an NGN, there is a more defined separation between the transport (connectivity) portion of the network and the services that run on top of that transport. This means that whenever a provider wants to enable a new service, they can do so by defining it directly at the service layer without considering the transport layer. That means services are independent of transport details. Increasingly applications, including voice, tend to be independent of the access network (de-layering of network and applications) and will reside more on end-user devices (phone, PC, set-top box).
NGN includes a wide range of protocols (including various profiles) at both service and network levels. Thus it is essential to ensure interoperability between different systems and networks.

After few more years we can have the advantages of NGN, They are

  • Reduced call charges
  • New innovative services
  • Single connection and bill for voice, data, video, mobile (Quad play)
  • Better QoS
  • Faster speed
  • Availability of Bandwidth on Demand

When we consider future telecom BT’s 21st Century Network, due to be completed by2012, will make the UK the first country to use an NGN for its national communications infrastructure. Challenges arising from switching to 21CN include maintaining the quality and security of the UK’s telecoms network and communicating the implications of the transition to consumers and businesses. As NGNs are introduced, they will connect with traditional networks through ‘gateways’ that translate signals in and out of IP. This is not technically difficult, but quality may be lost if a call travels through several such gateways. A more difficult problem is defining the technical standards and commercial model for ‘all-IP’ interconnects between competing NGNs and service providers.
Next Generation Network