Efficient Micro-Mobility using Intra-domain Multicast-based Mechanisms (M&M)

One of the most important metrics in the design of IP mobility protocols is the handover performance. The current Mobile IP (MIP) standard has been shown to exhibit poor handover performance. Most other work attempts to modify MIP to slightly improve its efficiency, while others propose complex techniques to replace MIP. Rather than taking these approaches, we instead propose a new architecture for providing efficient and smooth handover, while being able to co-exist and inter-operate with other technologies. Specifically, we propose an intra-domain multicast-based mobility architecture, where a visiting mobile is assigned a multicast address to use while moving within a domain. Efficient handover is achieved using standard multicast join/prune mechanisms. Two approaches are proposed and contrasted. The first introduces the concept proxy-based mobility, while the other uses algorithmic mapping to obtain the multicast address of visiting mobiles. We show that the algorithmic mapping approach has several advantages over the proxy approach, and provide mechanisms to support it. Network simulation (using NS-2) is used to evaluate our scheme and compare it to other routing-based micro-mobility schemes - CIP and HAWAII. The proactive handover results show that both M&M and CIP shows low handoff delay and packet reordering depth as compared to HAWAII. The reason for M&M's comparable performance with CIP is that both use bi-cast in proactive handover. The M&M, however, handles multiple border routers in a domain, where CIP fails. We also provide a handover algorithm leveraging the proactive path setup capability of M&M, which is expected to outperform CIP in case of reactive handover.Comment: 12 pages, 11 figure

Bidirectional ring, an interconnection network for shared-memory multiprocessor systems

grantor: University of TorontoA bidirectional ring is proposed in this thesis as an interconnection network for shared-memory multiprocessors to improve their performance and reliability. It consists of two rings transmitting packets in opposite directions. The constituent rings are bit-parallel and use the slotted access protocol. The bidirectional ring allows a request packet to traverse one ring from a source to the destination, and the response packet to return on the other ring; hence, a request and response transaction does not require traversal of the entire ring. This transmission protocol is advantageous in exploiting the communication locality of application programs to improve their performance. The existence of two rings in the bidirectional ring improves the reliability of the system. A cache coherence protocol is proposed for shared-memory multiprocessors using the bidirectional ring interconnect. The protocol ensures sequential consistency. A reliable implementation of this protocol is also given that can handle node and link failures. The fault handling logic is concentrated in the bypass path, which is activated only after detecting a fault, hence it does not affect the normal operation of the ring. The performance of the bidirectional ring is evaluated in comparison with a hierarchy of unidirectional rings. The simulation is performed using system parameters analogous to the NUMAchine prototype. A set of applications from the SPLASH-2 benchmark suite is used for this study. The bidirectional ring shows up to 50% lower latency than the hierarchy. Its performance is less sensitive to communication patterns. Comparing the overall performance with the hierarchy, the program execution time is reduced up to 30% on the bidirectional ring. The bidirectional ring also shows a tendency to balance the network load. The utilizations of the two constituent rings has been found to be within 5% of each other. The degradation in the performance of a faulty bidirectional ring is relatively low; a maximum increase of 6% in the execution time is found for all the benchmark applications we have simulated. The faulty ring shows the same load balancing characteristic of a good ring.Ph.D

Multicast-based Mobility: A Novel Architecture for Efficient Micro-Mobility

Handover performance is very important when evaluating IP mobility protocols. If not performed efficiently, handover delays, jitters and packet loss directly impact application performance. We propose a new architecture for providing efficient handover, while being able to co-exist with other protocols. We propose a paradigm for multicastbased micro mobility (M&M), where a visiting mobile is assigned a multicast address to use while moving within a domain. The multicast address is obtained using algorithmic mapping, and handover is achieved using multicast join/prune mechanisms. This study outline

Resource Allocation for Co-Existence of eMBB and URLLC Services in 6G Wireless Networks: A Survey

Next generation of wireless networks are characterized by two main features named Enhanced Mobile Broadband (eMBB) and Ultra Reliable Low Latency Communications (URLLC). These two services can be accommodated in the same wireless infrastructure so that wide range of users, demanding either massive throughput or extremely low latency and high reliability requirements, are directly benefited for providing various mission critical services. Co-existence of eMBB and URLLC services, however, demand highly efficient and less complex resource allocation schemes. In this paper, various resource allocation techniques are studied for the co-existence of eMBB and URLLC traffic to meet the heterogeneous specifications of each class of users. A detailed study on existing resource allocation schemes for simultaneous transmission of eMBB and URLLC services based on network slicing, flexible Transmit Time Interval (TTI), scheduling and distributed and federated learning are provided. Moreover, Machine Learning (ML) aided and Reconfigurable Intelligent Surface (RIS) and Unmanned Aerial Vehicle (UAV) assisted resource allocation techniques are also studied in detail. Additionally, this paper identifies some challenges for eMBB and URLLC service accommodations in the same wireless architecture, and proposes their possible solution approaches

Abstract A Study of Profiled Handoff for Diffserv-Based Mobile Nodes

There is a growing interest in providing Internet services to the mobile nodes. When mobile nodes travel from one router's service area to another, the time-sensitive applications may see degradation in service. We investigate into the effects of handoff on service quality of mobile nodes. Several experiments are conducted using various packet metering and marking schemes with or without transferring profiles to the new router. Results indicate the relative instability period following handoff, loss of packets and delay encountered by packets in profiled or un-profiled handoffs, leading to determining suitable mix of metering and marking schemes with or without context transfer. Best effort service has been acceptable for traditional Internet applications like web, email and file transfer but it is inadequate for new classes of applications such as audio and video streaming. These new applications demand high data throughput and lo