Fast recovery protocol for database and link failures in mobile networks

The design of TCP/IP is the key of the success of Internet. Due to the network considered as a “black box”, the congestion control algorithm becomes the most important part of TCP. TCP Westwood provides an eligible rate estimation algorithm that improves upon the performance of TCP Reno in wired as well as wireless networks. The improvement is most significant in wireless networks with lossy links. In mobile communication, due to the node mobility, the bandwidth shifting requires higher demands to QoS. In mobile networks with high bandwidth, such as 3G/LTE, the bandwidth will shift rapidly in different positions. We call this bandwidth instability, which is the cause of the degradation of performance. However, Westwood TCP or the other popular TCP cannot response quickly to this situation. In this paper, we verify the problem mentioned above of varied TCP protocols. After that, we propose an improved fast recovery mechanism based on Westwood TCP. The new mechanism can adjust the congestion window in time when the bandwidth shifts.

Download Full-text

Software-Defined Networking Switches for Fast Single-Link Failure Recovery

Journal of Interconnection Networks ◽

10.1142/s0219265918500147 ◽

2018 ◽

Vol 18 (04) ◽

pp. 1850014

Author(s):

DAWEI LI ◽

JIE WU ◽

DAJIN WANG ◽

JIAYIN WANG

Keyword(s):

Network Topology ◽

Routing Protocols ◽

Shortest Paths ◽

Software Defined Networking ◽

Failure Recovery ◽

Link Failure ◽

Fast Recovery ◽

Link Failures ◽

Single Link

In this paper, we consider IP fast recovery from single-link failures in a given network topology. The basic idea is to replace some existing routers with a designated switch. When a link fails, the affected router will send all the affected traffic to the designated switch (through pre-configured IP tunnels), which will deliver the affected traffic to its destination without using the failed link. The goal of the approach is to achieve faster failure recovery than traditional routing protocols that employ reactive computing upon link failures. Software-Defined Networking (SDN) switches can serve as the designated switches because they can flexibly redirect affected traffic to other routes, instead of only to the shortest paths in the network. However, SDN switches are very expensive. Our objective is to minimize the number of SDN switches needed and to guarantee that the network can still recover from any single-link failure. For networks with uniform link costs, we show that using normal non-SDN switches with IP tunneling capability as designated switches can guarantee recovery from any single-link failure. For networks with general link costs, we find that not all single-link failures can be recovered by using non-SDN switches as designated switches; by using SDN switches only when necessary, we can reduce the total number of SDN switches needed compared to an existing work. We conduct extensive simulations to verify our proposed approaches.

Download Full-text

Link Recovery Scheme for Multi-Point mmWave Communications

Electronics ◽

10.3390/electronics9010050 ◽

2019 ◽

Vol 9 (1) ◽

pp. 50

Author(s):

Adel Aldalbahi

Keyword(s):

Mobile Station ◽

Base Station ◽

Fast Recovery ◽

Link Failures ◽

Access Scheme ◽

Directional Transmission ◽

Recovery Scheme ◽

Recovery Times ◽

Efficient Power ◽

Recovery Schemes

Directional transmission in millimeter wave (mmWave) communications results in prolonged access times. This is attributed to the increased number of conducted measurements to determine optimum beam directions at the mobile station (MS) and base station (BS) that return the highest received signal levels. Additionally, once these beams are determined and links are established for data-planes, then blockage effects and outages make these links more vulnerable to link failures, resulting in communications drops. Hence, dynamic and fast recovery schemes are required to maintain communications sessions following the beam access stage. In this paper, a novel recovery access scheme is proposed for multi-point mmWave communications based on fog access points (AP). Namely, the scheme leverages diversity and network coding techniques to achieve near-instantaneous recovery times, without the need for beam scanning. The scheme features near-instantaneous data recovery times and efficient power consumption as compared to traditional recovery methods.

Download Full-text