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Published in Gillian M. Davis, Noise Reduction in Speech Applications, 2018
By its very nature, IP is an unreliable networking protocol. In its most basic (and ubiquitous) form, IP makes no delivery, reliability, flow control, or error recovery guarantees and can, as a result, lose or duplicate packets or deliver them out of order.3 IP assumes that higher layer protocols or applications will detect and handle any of these problems. Obviously, this kind of network behavior can be problematic for real-time VoIP. When an IP packet carrying digitized voice is lost, the voice signal will be distorted. Before describing the kinds of distortion packet loss can create, it is useful to briefly describe the causes of packet loss:11Packet damage: Many applications will discard incoming packets when presented with one that has been damaged. An example of packet damage is bit errors due to circuit noise or equipment malfunction.Network congestion, buffer overflow, and IP routing: Perhaps the largest cause of packet loss is packet discard due to network congestion. When a particular network component receives too many packets at one time, its receive buffers overflow causing packets to be discarded. IP networks also deal with network congestion by rerouting traffic to less congested network paths, but this can increase delay and jitter.
Digital Video Transmission
Published in Goff Hill, The Cable and Telecommunications Professionals' Reference, 2012
Packet loss is when packets go missing in a network. The principal cause of packet loss is when sources overload network elements. As a network becomes congested, forwarding nodes cannot process the data at the rate at which it arrives, and it is therefore discarded by the overflowing buffers. Other loss due to equipment failure or bit error caused by interference can occur but is in general rare. Bursty traffic is particularly adept at causing buffer overflow, and the convergence of a number of VBR traffic sources at a network element (such as a router) can soon overload the buffer capabilities. Packets can also be discarded if they have been delayed. An IP packet has a Time-to-Live (TTL) stamp, which when decremented to 0 results in the packet being discarded (Peterson & Davie, 2000; Tanenbaum, 2003). This can actually be desirable because for real-time traffic the playout time at the receiving codec is likely to have passed.
Requirements of Metropolitan Area Network Services
Published in Nam-Kee Tan, MPLS for Metropolitan Area Networks, 2004
Packet loss is associated with the reliability aspect of VoIP, and it can be due to network link congestion in which router buffers are exhausted by many traffic streams and start to drop packets. Packet loss also occurs when a network link/node fails. For non-real-time applications such as file transfers and e-mail, packet loss is nonvital because these data applications use Transmission Control Protocol (TCP) to provide retransmission to recover dropped packets. However, in the case of real-time voice applications, voice packets have to reach the receiver end within a rather small time window to remain valid in the reconstruction of the original voice signal. Retransmissions in the voice situation would add a sizeable delay to the reconstruction and would result in clipped or unintelligible speech. To prevent packet loss for VoIP from happening, QoS prioritization schemes and flow control mechanisms must be deployed accordingly along the network path that is traversed by the voice traffic. In addition, the routing environment must be able to provide fast restoration to any link/node failures and topology changes to bolster network reliability, which in turn prevents unnecessary packet loss. Table 1.4 gives the reader a rough guide of the QoS requirements for some multi-service applications in a MAN setting.
Vertical handover in heterogeneous networks using WDWWO algorithm with NN
Published in International Journal of Electronics, 2021
M Naresh, D Venkat Reddy, K Ramalinga Reddy
Resultant graph 9(a) shows the PDR range vs packets per second. A number of packets increases, the PDR range will be decreasing, and data traffic also increases. At 10packets per second, the generation of PDR is 99.5% and reduces the number of packets PDR range is 97%, 95%, 93% and 92% as 20, 30, 40 and 50packets/sec. When compared with existing methods, PDR is 87%, 78% and 75% of D-TOPSIS, FIS-ENN, and F-AHP respectively at 50 packets/sec. Packet loss occurs when one or more data packets travelling over a network fail to reach their destination. Packet loss is affected by errors in the transmission of data. (Figure 9(b)) displays the packet loss. At 10, 20, 30, 40, and 50 packets/sec, ODRN shows the packet loss of 2%, 7%, 11%, 15% and 19% respectively. It is better than the existing methods of D-TOPSIS (24%), FIS-ENN (32%) and F-AHP (37%) for 50 packets/sec.
Lifetime improved WSN using enhanced-LEACH and angle sector-based energy-aware TDMA scheduling
Published in Cogent Engineering, 2020
Ramadhani Sinde, Feroza Begum, Karoli Njau, Shubi Kaijage
The average packet loss in each work is shown in Table 3, where the proposed E-LEACH is very low that the other two works. Let assume 200 packets are transmitted in total, among which nearly 6 to 7 packets are dropped and hence an average of 4% of packet loss occurs in proposed work. The increase in packet loss results in degraded performance. Approximately 12% of packet loss is minimized in E-LEACH when compared with LEACH protocol. Nearly 9% of packet loss is reduced from TTDFP work. This minimization shows improvements in other network parameters and the impact in the proposed system to sustain nodes with prompt data delivery. Increase in packet loss creates poor impacts over the designed system model. The reduction in packet loss shows the effectiveness of the method applied for data transmission. (d) Effectiveness of energy consumption
Backstepping control for stochastic nonlinear strict-feedback systems based on observer with incomplete measurements
Published in International Journal of Control, 2022
Lidong Wang, Xiaoping Liu, Xinze Xue, Yingxin Wei, Tong Li, Xuebo Chen
Packet loss can be caused by many reasons, such as physical limitation of wireless network and time-division multiplexing of a communication channel. In addition, when communication network is attacked, such as denial-of-service attacks, data will be damaged. Data is not available in both cases and we call them data-losing case. In this situation, some works such as An and Yang (2018) just discard the data and let observation data be zero, which will degrade state estimation performance. In this paper, the last normal observation value is adopted to replace the losing data, which can reduce the measurement loss to a certain extent.