This thesis informs about currently used technologies, which provide loop protection on data link layer of computer networks. It clarifies issues of Ethernet networks. Chosen protocols are then closely described. There are presented advantages and disadvantages of chosen protocols and they are compared to other technologies. Practical section describes the initial implementation of IS-IS in OMNeT++ environment, which serves as the basic building block of TRILL protocol. An important issue is to verify correctness of implementation.

With a new United States Army initiative to exploit commercially developed information technology, there is a heightened interest in using Internet protocols over the military's geosynchronous satellite links. TCP is the dominant Internet protocol used for reliable data exchange, but its own design limits performance when used over long delay network links such as satellites. Initially this research set out to compare TCP with another proposed protocol, the Satellite Transport Protocol (STP). However through a series of tests, we found that STP does not fulfill its claims of increased throughput over TCP and uncovered a flaw in STP's founding research. In addition, this thesis proposes and demonstrates novel performance enhancing techniques that significantly improve transport protocol throughput.

Wireless systems with multiple antennas at both the transmitter and receiver (MIMO systems) have been the focus of research in the recent past due to their ability to provide higher data rates and better reliability than their single antenna counterparts. Designing a communication system for MIMO frequency selective channels provides many signal processing challenges. Popular methods like MIMOOFDM and space-time precoding linearly process blocks of data at both the transmitter and the receiver. Independence between the blocks is ensured by introducing sufficient redundancy between successive blocks. This approach has many pitfalls, including the limit on achievable data rate due to redundancy requirements and the need for additional coding/processing. In this thesis, we provide a filterbank precoding framework (FBP) for communication over MIMO frequency selective channels. By viewing the channel as a polynomial matrix, we derive the minimum redundancy required for achieving FIR equalization of the precoded channel. It is shown that, for most practical channels, a nominal redundancy is enough. The results are general, and hold for channels of any dimension and order. We derive the zero-forcing and MMSE equalizers for the precoded channel. The role of equalizer delay in system performance is analyzed. We extend the minimum redundancy result to the case of space-time filterbank precoding (STFP). Introducing the time dimension allows the channel to be represented by a block pseudocirculant matrix. By using the Smith form of block pseudocirculant matrices, we show that very high data rates can be achieved with STFP. When channel information is available at the transmitter, we derive an iterative algorithm for obtaining the MMSE optimal precoder-equalizer pair. We then provide a comparison of FBP with the block processing methods. It is shown that FBP provides better BER performance than the block processing methods at a lower computational cost. The reasons for the better performance of FBP are discussed.

This work shows and implements possibilities of OSI Layer-2 Network Topology Discovery based on information from Cisco Discovery Protocol, Spanning Tree Protocol and Switches' Filtering Databases. / Diese Arbeit zeigt und implementiert Möglichkeiten zur OSI Layer-2 Netzwerk Topologie Erkennung basierend auf Informationen des Cisco Discovery Protocol, Spanning Tree Protocol und Switch Filter Datenbanken.

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This work shows and implements possibilities of OSI Layer-2 Network Topology Discovery based on information from Cisco Discovery Protocol, Spanning Tree Protocol and Switches' Filtering Databases. / Diese Arbeit zeigt und implementiert Möglichkeiten zur OSI Layer-2 Netzwerk Topologie Erkennung basierend auf Informationen des Cisco Discovery Protocol, Spanning Tree Protocol und Switch Filter Datenbanken.

<p>One of the most parts of VOIP management is fault management and, in having a good fault management, finding good mechanisms to detect faults in the network have to be considered.</p><p>The main focus of this project is to implement different types of fast fault recovery protocols in networks<strong>,</strong> especially networks that carry IP telephony. Having a complete understanding of some common link failure detection and fault recovery protocols<strong>,</strong> such as spanning tree protocol (STP), rapid spanning tree protocol (RSTP) and per-VLAN spanning tree protocol (PVSTP)<strong>,</strong> and also having a complete understanding of three other common techniques for fault detection and fault recovery, such as hot standby routing protocol (HSRP), virtual router redundancy protocol (VRRP) and gateway load balancing protocol (GLBP) will be regarded in the project. We are going to test some fault recovery protocols which can be used in IP telephony networks and choose the best. We intend to focus on this issue in LAN environment in theoretical descriptions and practical implementations.</p><p>The final outcome of the thesis is implementation in the Halmstad University’s lab environment to obtain the final result. For doing our thesis, we are going to use some technical tools as hardware tools (Cisco L3 and L2 switches, Routers, IP Phones) and tools which are used for network performance monitoring<strong>,</strong> like as CommVeiw.</p>

One of the most parts of VOIP management is fault management and, in having a good fault management, finding good mechanisms to detect faults in the network have to be considered. The main focus of this project is to implement different types of fast fault recovery protocols in networks, especially networks that carry IP telephony. Having a complete understanding of some common link failure detection and fault recovery protocols, such as spanning tree protocol (STP), rapid spanning tree protocol (RSTP) and per-VLAN spanning tree protocol (PVSTP), and also having a complete understanding of three other common techniques for fault detection and fault recovery, such as hot standby routing protocol (HSRP), virtual router redundancy protocol (VRRP) and gateway load balancing protocol (GLBP) will be regarded in the project. We are going to test some fault recovery protocols which can be used in IP telephony networks and choose the best. We intend to focus on this issue in LAN environment in theoretical descriptions and practical implementations. The final outcome of the thesis is implementation in the Halmstad University’s lab environment to obtain the final result. For doing our thesis, we are going to use some technical tools as hardware tools (Cisco L3 and L2 switches, Routers, IP Phones) and tools which are used for network performance monitoring, like as CommVeiw.

This Diploma Thesis deals with problems of marketing strategy proposal for the company ZDT spol. s.r.o. – Agriculture and transport machinery Ltd. A marketing strategy proposal based on theoretical knowledge, analysis of the company’s current condition and questionnaire survey is introduced. This proposal should lead to strengthening our position on domestic market, gaining new market outlet and as a result of this to higher sales and profits.

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