The desire to improve the overall performance of IP network leads to designing new
QoS achitectures. The new Enhancement in providing quality of service (QoS) on the
Internet is based on the Different Services (DiffServ). DiffServ divides traffic i
nto small
classes and allocates network resources on a per-class basis. In this architecture, packets
are marked with different DiffServ code points (DSCP) at edge routers, and the priority for
packets is given via the value of this field. On the other hand, MPLS is a fast forwarding
mechanism that depends on Label's. The main advantage of MPLS is its support for traffic
engineering which results in best utilization of network's resources like link capacity. The
integration of using MPLS (as a forwarding mechanism) with DiffServ (as a QoS
mechanism) offer high Quality of service especially for real time applications (such as
VoIP, Video Conference).
We evaluate the performance of MPLS-DiffServ networks in our research. We study
QoS metrics as delay, variation of delay, upload response time, link utilization, packet loss
for several kinds of traffic (Voice, Video, FTP) by using OPNET Simulator and we
showed its superiority over MPLS network and pure IP ones. We compare our results with
MPLS networks and pure IP ones. Our results showed superiority of MPLS-DiffServ over
other kinds of networks. This is clear in decreasing delay ,delay variation, upload response
time, queuing delay, reduction of lost packets and best utilization of link capacity.
The process of transfer a speech signal by high confidentially and as quickly as possible through the Internet needs to develop compression and encryption technology for a speech signal, so as, to reduce its size and make it understandable to persons
not authorized to listen to.
A system was designed to encrypt the voice over Internet Protocol (VoIP) and use compression technique for the purpose of reducing the size of data and send it over the network, (A_law PCM) algorithm was used the to compress audio data. Then algorithms of Triple Data Encryption Standard (TDES) and Advanced.
Encryption Standard (AES) were applied. A new encryption algorithm was proposed based in its work on the block cipher encryption system called the Direct and Reverse algorithm, which based on three basic steps, firstly expand the initial key, secondly direct the encryption of each round in one direction, and finally substitute (Bytes) as used in the Compensation Box in AES algorithm by making it moving. In general compression ratio was calculated and it was (50%) and the results of the correlation coefficient for the proposed algorithm was compared with the results of (AES, TDES) algorithms.
