Single-radio Shared Wireless Mesh in .NET Generator qr-codes in .NET Single-radio Shared Wireless Mesh

How to generate, print barcode using .NET, Java sdk library control with example project source code free download:
10.3 Single-radio Shared Wireless Mesh use visual studio .net qr barcode implementation toembed qr code with .net bar code In a single-radio mesh, each QR Code JIS X 0510 for .NET mesh AP node acts as a regular AP that supports local Wi-Fi client access as well as forwarding traffic wirelessly to other mesh points. The same radio is used for access and wireless mesh links.

This option has the advantage of providing the lowest cost deployment of a wireless mesh network infrastructure. However, each mesh AP typically uses an omni-directional antenna to allow it to communicate with all of its neighbour mesh APs, where all the mesh APs share the same channel for their mesh links..

220 Capacity of Wireless Mesh Networks Further, in a single-radio s Visual Studio .NET qr codes hared mesh every packet generated by local clients must be repeated on the same channel to send it to at least one neighbouring mesh AP. The packet is thus forwarded to successive mesh nodes and ultimately to the mesh portal that is connected to a wired network.

This packet forwarding generates excessive traffic on the channel shared by all the mesh links and clients. As more mesh APs are added, a higher percentage of the wireless traffic in any cell is dedicated to mesh link forwarding. Very little of the channel capacity is available to support users.

The impact of mesh forwarding is that capacity varies with between 1/N times the channel capacity and (1/2)N times the channel capacity where N is the number of mesh link hops in the longest path between a client and the wired infrastructure mesh portal.. Number of Mesh APs Figure 10.2: Single-Radio Shared Mesh Per-AP Capacity, Mesh Portal at End. Figure 10.2 shows mesh AP ca pacity estimates for a single-radio Wi-Fi mesh network using these equations. Shared radio meshes always display the undesirable characteristic that user capacity available at each mesh AP declines as you add more mesh APs to the network and increase the number of wireless links.

The starting capacity of 5 Mbps assumes a single channel of 802.11b, which has a raw data rate of 11 Mbps and useful throughput measured at the TCP/IP layer of about 5 Mbps. This throughput is shared between the access traffic and the mesh link traffic in a single-radio mesh.

This is the maximum throughput available in an 802.11b system. As distances from the AP increase, throughput will of course decrease with the varying modulation schemes used by 802.

11. The results presented here will still be valid for an entire cell, but should be scaled accordingly. The choice of model to use, 1/N or (1/2)N, will vary with the topology of the mesh, the location of the mesh portal and the extent of the interference domain between mesh APs.

The interference domain describes the number of nodes in the mesh whose transmissions will be sensed by and hence block the transmission of other nodes. More details on this can be found in the Appendix. The 1/N model is obviously the most.

Capacity of Wireless Mesh Networks 221 optimistic. In all cases, ca pacity available in each mesh cluster declines rapidly as more mesh APs are added. There are mesh routing protocols that can optimize the forwarding behaviour and eliminate unnecessary transmissions.

But the best these optimizations can do is to bring the network closer to 1/N performance. It should be noted that these analysis assume perfect mesh forwarding, no interference and perfect coordination of the Wi-Fi channel access. Actual delivered throughput and capacity will usually be lower.

. Figure 10.3: Single-Radio Mesh Architecture, String of Mesh APs. Consider a linear string of mesh APs arranged so that each one can sense only one adjacent neighbour on either side (Figure 10.3), that is, with an interference domain of one node. This is not a likely real world deployment, but it simplifies the analysis and we will use this example to compare each of the wireless infrastructure mesh approaches.

Throughout this chapter we will also assume that client access load is evenly distributed across the mesh APs. In this string of mesh APs with the mesh portal on the end, N the number of hops from Figure 10.4, is same as the number of mesh APs.

The total channel capacity is 5 Mbps. It can be seen that in this topology the best case 1/N performance is not achievable. N=5, so each AP should have 1 Mbps of capacity.

All of the traffic from the entire mesh cluster will have to flow through AP5 to get to the wired portal. If each mesh AP accepts a load of exactly 1 Mbps of traffic from its clients, then AP5 will have to forward 4 Mbps of traffic from APs 1, 2, 3 and 4; and has exactly 1 Mbps of capacity left for its local clients. This analysis assumes perfect contention and collision management.

If that is not the case, then more collisions and re-transmissions will result in further congestion and still lower capacity than shown by the simplified analysis. In a single-radio Wi-Fi mesh network, all clients and mesh APs must operate on the same channel and use the 802.11 Media Access Control (MAC) protocol to control contention for the physical medium.

As a result, the entire mesh ends up acting like a single access point - all of the mesh APs and all of the clients must contend for a single channel. As we have seen, this shared network contention and blocking reduces capacity. It also introduces unpredictable delays in the system as forwarded packets from mesh APs and new packets from clients contend for the same channel.

Copyright © . All rights reserved.