Latency/Jitter Degradation on Single Channel Backhauls in .NET Generate qr codes in .NET Latency/Jitter Degradation on Single Channel Backhauls

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15.4 Latency/Jitter Degradation on Single Channel Backhauls using vs .net toadd qr code on web,windows application gs1 bar code 128 Latency is inve VS .NET Denso QR Bar Code rsely related to available bandwidth: thin pipes can provide only so much flow. Single channel backhauls suffering from bandwidth degradation also suffer from poor latency and jitter over multiple hops.

This is primarily due to the need for a single radio to serve both backhaul and client traffic. The result is that most First Generation single-. 320 First, Second and Third Generation Mesh Architectures channel backhau Visual Studio .NET qr bidimensional barcode l networks provide reliable video- or voice service over only one- or two hops. As a result many more costly wired or fiber Internet or intranet drops are needed to deliver adequate service, increasing the ongoing total cost of ownership.

Third Generation mesh products do not suffer from bandwidth degradation they use multiple backhaul radios to obviate radio channel interference. Field tests indicate a latency of less than 1 millisecond per hop even under heavy traffic. Since latency is thus not a factor of traffic or user density, jitter (variation in delay) is also very low.

This makes Third Generation products suitable for networks serving large number of users, demanding applications, video, and voice - even simultaneously. These capabilities of Third Generation wireless mesh networks make them especially useful where video surveillance is part of a metro/muni requirement, for expanding coverage into under-served areas with limited high speed wired or fiber infrastructure, and for border and perimeter networking, where bandwidth must be extended node-to-node as if in a long string of pearls. Additionally, MeshDynamics multi-radio backhauls also incorporate VoIP concatenation for timely VoIP packet delivery.

VoIP packets are small typically less than 300 bytes but sent frequently, generally once every 20 milliseconds. Networking protocols like CSMA/CA do not transport small and time sensitive packets well. The VoIP concatenation engine aggregates small VoIP packets into a larger packet for more efficient delivery.

This aggregation takes place every 5-10 milliseconds. USAF tests (Figure 15.4) show overall latency is less than 10 ms + 1 ms per hop over a 4 hop network.

Jitter is less than 1 ms per hop.. Figure 15.3: Live Feed from a multi-hop dual channel backhaul. First, Second and Third Generation Mesh Architectures 321 One way delay e xperienced by the 36 simultaneous callers: Latency with Concatenation is 10 ms + 1 ms per hop. Figure 15.4a: L Visual Studio .NET QR Code 2d barcode atency for 36 simultaneous VoIP calls over a 4 hop Mesh Network running VoIP Concatenation over the backhaul.

. Jitter experienced by 36 simultaneous callers. Less than 4 ms average over 4 hops. Figure 15.4b: J QR Code for .NET itter for 36 simultaneous VoIP calls over a 4 hop Mesh Network running VoIP Concatenation over the backhaul.

. 322 First, Second and Third Generation Mesh Architectures USAF tests foun QR for .NET d comparable latency/jitter for single channel backhauls to be an order of magnitude higher. Some reasons for this: Bandwidth degrades with each hop.

As an analogy to water pipes, the smaller the pipe, the slower the flow. With all radios on the same channel, there is compounded contention will packets fighting each other, all on the same channel. The overall efficiency of the CSMA/CA protocol used degrades exponentially as the number of clients on the same channel increase.

. 15.5 Frequency Agility through Distributed Intelligence Wireless is a s Denso QR Bar Code for .NET hared medium. Radios communicating on the same channel and within range of each other contend for available bandwidth.

In single channel backhauls, there is one radio acting as the repeater between nodes: all backhaul radios must be on the same radio channel. The entire network is susceptible to channel interference/jamming. System performance is compromised.

Figure 15.5 shows how the dual channel backhaul can switch channels to avoid debilitating external interference effects. This first step of providing two-radio backhauls provides an obvious theoretical advantage over single-channel backhauls, but management of channel selection and interference avoidance becomes a challenge addressed in a number of different ways.

One of the first approaches applied to this problem was to segregate the backhaul links with hardware radio switching and sectored directional antennas. Since each sectored antenna sees only a narrow field of view, radio emissions from adjacent nodes do not create interference. The limitations of this hardware-centric approach are the costs of sectored antennas and custom-developed radio hardware, the relative inflexibility of the system in dealing with perturbations and new external interference sources, and the complexity of sitesurveying and installation.

The alignment of the directional antennas must be precise and installation must include some manual determination of channel choices to maximize the efficient use (and re-use) of channels as well as a manual configuration of network topology. A more-recent alternative approach utilized by MeshDynamics automates the channel-selection and topology-definition tasks by distributing dynamic radio intelligence in each node, in effect creating multiple RF robots . Sophisticated algorithms allow each node to listen to its environment continuously to determine its relationship with neighboring nodes as well as extraneous and potentially interfering radio sources.

Based on this analysis of the environment, an individual node selects the best channels to use to connect to the optimal nearby node for highest performance. In this distributed dynamic radio intelligence approach, the network forms a tree-like structure emanating from one or more root nodes that have the wired or fiber connection to the Internet or intranet. As the branches of the tree radiate outward, eventually they become geographically distant enough from one another for nodes to begin re-using channels.

This greatly increases the data-carrying capacity of the network, since it makes.
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