Overview
This post discusses easy methods to develop training video above wireless performance. Many organizations are applying various new movie articles technologies today for example survive video clip streaming, webcasting, video conferencing and online conferencing. YouTube expertise stay popular and so are making use of more and more far more bandwidth as organizations use training video with regard to teaching and promoting purposes. Google words translation provider is now able to turn text, generating that English text message dependent movies designed to some other countries as well. Keep around head that with all the proliferation connected with provider VPNs intended for safety purposes, staff will use handheld in the office when seamlessly because at home or for a court network. They can easily access the identical movie companies from anywhere. This is the reason why cellular is and so common right now and the requirement for training video grade cellular infrastructu re performance.
The recent 80.11a/g cellular admittance position can be simply swamped when a few clientele start saving substantial files along with running training video applications. The greatest solution intended for guaranteeing ideal video clip overall performance is already the 802.11n the now necessary wireless standard. According to some Cisco predict study, the quantity of the now necessary wireless gadgets will certainly discuss wired systems around the world wide web by 2015 plus consideration intended for 54% of IP traffic. In addition video clip targeted visitors will probably akun to get 90% belonging to the customer online targeted visitors through 2015.
Video Basics
Video plus voice are generally real-time traffic streams by nature that are sensitive to network congestion plenty of latency (delay). Video offers both equally some sort of data plus an sound recording component. It must be listed which the exact same operation metrics for instance jitter, latency, bundle reduction and also throughput have an effect on video when well seeing that tone of voice site visitors throughout online along with company network. Packet reduction has a greater outcome on video though latency affects voice a great deal more. Guaranteeing precise assistance amounts for video about the network may possibly need applying QOS, escalating network bandwidth, system design changes and machines changes. All these types of changes usually are with the objective with creating your system "video ready". Companies progressively more work with web conferencing, webcasts as well as video conferencing regarding gatherings and also for training purposes. Colleges us e it to deliver training when well. It will be a very cheap application in order to lower company journey costs.
Types regarding Video
It is worth dealing with the many different types of movie companies popular currently and also where, from some sort of web 2 . 0 perspective, people form that content. Note how almost all of the expert services are all around the particular internet.
�Live Video Streaming online connected with provider Webcasts in addition to TV broadcasts typically transported to your current desktop.
�Web Conferencing on the desktop by using software like Skype and the very popular Go to be able to Meeting service.
�Video Conferencing assistance that will owns through as well as over the corporation network along with Cisco Telepresence plus equipment through firms just like Tandberg and Polycom.
�Progressive Video download from businesses just like YouTube to the desktop.
�Broadcast Video multicast with you to definitely numerous training video revenues like Netflix.
Video Performance
H.323 defines a collection of networks to get music plus movie targeted visitors like H.264 and also G.729 protocols. It will be your shape with regard to establishing hiburan purposes using a business network. The G.729 protocol is usually a well-known acustic codec to get compressing music traffic during 8 Kbps with a 10 ms delay. The H.264 video clip codec normal is the most up to date adopted movie data compresion standard. It specifies 24, 30 as well as 60 frames for every next (fps) to get excessive classification (HD) movie conferencing along with data compresion from 1.5 Gbps connected with video tutorial targeted traffic to 4 Mbps with a solution involving 1920 x 1080 along with 30 fps.
It is vital to understand the overall performance metrics which have an impact on online video media performance like packet loss, latency, jitter along with throughput. Video is actually despatched as a continuous stream involving traffic unlike records visitors for instance e-mail that may be re-transmitted using many hold off and possess very little important relation to company level. Congestion will be standard indication of the network this will be busy in addition to going through circle performance problems. The lists are usually busier through times of amplified multi-level activity. This causes increased latency, jitter, packet loss, dropped throughput plus re-transmission of packets. Implementing good quality regarding program (QOS) will probably often basically bring about fallen records packets to avoid voice/video packet loss. The records packets are then re-transmitted along with some delay. The adhering to defines these kinds of industry standard functional ity metrics.
Latency: Amount of your respective for a packet to visit through resource in order to destination
Jitter: Amount with typical variation in latency of every packet
Packet Loss: Percent of packets slipped from reference to be able to destination
Throughput: Average lots of packets routed throughout a preset period regarding time
Each online video media provider needs various quantities regarding bandwidth. Some services like video conferencing are definitely affected by improved latency, packet loss and jitter as compared to computing applications. For satisfactory video conferencing performance, the actual bundle loss must not exceed 1%, jitter 30 ms and a one-way latency involving more than two hundred microsoft (latency regarding a hundred and fifty ms intended for higher description online video media conferencing resolution). When these kinds of thresholds are maxed the picture can deteriorate. Bandwidth requirements to get video clip are caused by the specific sort of service, quantity involving resolution and also frames every second. For case in point a regular online video media conferencing resolution involving 704 x 576 at 30 fps needs 768 Kbps - 1 Mbps with bandwidth when a High Definition (HD) resolution regarding 1080 x 1920 with 30 fps demands 4 Mbps - 12 Mbps. Desktop companies for instance surging training video and internet conferencing have lower bandwidth needs compared to video conferencing, nevertheless the same latency, jitter in addition to packet loss difficulties have an impact on video performance. In accessory having almost all services, you need to add the average of 20% added bandwidth cost pertaining to Ethernet as well as IP method processing.
Video Quality regarding Service (QOS)
Implementing level of quality connected with company (QOS) using a organization multi-level is usually an ending to get rid of process commencing having the online video media approach source. Video conferencing finish details will often be attached to a company borders switch whilst video streaming into the computer help will be internet based. The procedure for developing any QOS entails prioritizing page views to get preferential service. Considering video clip conferencing, the actual Cisco 3560 along with 3750 access advantage changes are often accustomed to link video clip equipment. The part only two facts shape includes an 802.1p header having 3 rolls that may be placed for 8 different class associated with service (CoS) prices through 0 - 7. For occasion movie is usually given CoS regarding some though style packets tend to be assigned CoS connected with your five along with the increased variety gets far better service. High concern facts is often assigned CoS co nnected with 2.
DSCP is a coating 3 QOS protocol utilized to lay down various kinds involving assistance (ToS) lessons for data, words and movie traffic. DSCP attitudes are usually layer 3 therefore are emerge the primary 6 rolls with the IP Precedence field from the IP header. The very best perform suggestion out of Cisco to get tagging training video may be a DSCP involving AF41. Data page views is definitely assigned your decrease goal just like AF21 for example while express can be allocated a larger main concern associated with DSCP EF. Video targeted traffic will be classified along with access lists that determine training video site visitors including a class map is definitely explained for movie that fits a great accessibility list and points to a distinct policy map. The protection plan map should the particular DSCP observing connected with video targeted visitors as well as DSCP valuation can be allocated into a queue. Class of program (CoS) packets is often fixed which includ es a scheme map but it surely is often marked with admittance goes along with SRR sufficient reason for WRR with distribution/core switches.
Shaped Round Robin (SRR) is usually a equipment centered queuing technique deployed using obtain switches. SRR allows stratum 2 category of service (CoS) along with stratum a few (ToS) mappings to queues. The submitter along with core community layers generally have 6500 Cisco goes and they also apply Weighted Round Robin (WRR) equipment queuing. WRR may be the same idea however the queuing structures is definitely relatively diverse and also merely core 2 training associated with service values will be mapped to be able to queues.
WAN routers are generally used by using Low Latency Queuing (LLQ) plus Class Based Weighted Fair Queuing (CBWFQ) that will assigns video site visitors on the high priority queue which includes a specific main concern proportion like seeing that 15%. That warranties many video clip traffic will receive 15% from the website bandwidth. For instance a one particular Gbps Metro Ethernet circuit will certainly allocate 150 Mbps with bandwidth to video clip targeted traffic without method overhead. Company WAN back links like a best process don?t want to exceed approximately 33% regarding available bandwidth for all those words in addition to training video traffic. That retains space for method cost to do business plus facts packets. Data site visitors overall performance worsens since packets are usually lowered and also video clip targeted traffic QOS turns into much less effective.
Desktop uses create a savings fund very same QOS resources nonetheless the organization internet connection plus the wireless circle element straight into that design. In add-on the public cellular multi-level you come about for being using affects that overall video circle performance. The bandwidth of your respective property internet connection along with congestion impinges on overall performance as well as any kind of blockage things along the network. The handheld network will be frequently where movie operation degrades specially on an 802.11b public network.
Wireless Standards
These explain that industry typical handheld methodologies currently deployed.
80.11b
This instant standard accepted around 1999 specifies a new greatest files amount associated with eleven Mbps with the 2.4 GHz unlicensed group of musicians inside United States. The band suffers from a lot of disturbance from commercial gadgets employing that frequency. The common from the United States assigns 11 routes along with bandwidth of close to 80 MHz at 5 various MHz per channel. The United States allocates 3 or more non-overlapping avenues associated with 1, some along with 11 using a center frequency broken relationships associated with 25 MHz for every channel. The modulation system utilised by using 802.11b is definitely Direct Sequence Spread Spectrum (DSSS) along with CCK with characteristics that minimize side effects related having interference. The 802.11b additional information prices incorporate 1, 2, in addition to 5.5 Mbps.
802.11g
This wireless normal authorised throughout 2003 specifies a optimum files rate regarding 54 Mbps with all the exact 2.4 GHz group because 802.11b. The 802.11g standard is usually popular with greater throughput and increased coverage. The exact same interference problems arise even so with the 2.4 GHz band. The 802.11g works iwth with all the 802.11b ordinary along with assigns the particular very same 11 options along with 1, some and 11 because non-overlapping. The modulation plan used in combination with 802.11g is OFDM that will specifies bigger information rates. The further 802.11g facts fees include 1, 2, 5.5, 6, 9, 11, 12, 18, 24, 36 in addition to twenty four Mbps.
802.11a
This wireless standard had been approved throughout 1999 specifying some sort of maximum data amount involving 54 Mbps using this 5 various GHz unlicensed music group inside the United States. The advantage of 802.11a is definitely higher throughput however the cellular policy is actually scaled-down in addition to additional admittance items will probably be required for identical 802.11g coverage. There is a lot less interference from units like wireless phones, bluetooth devices, microwaves in addition to financial equipment using the 2.4 GHz band. There will be 23 non-overlapping programmes when using the current 802.11h specification. Some Cisco gadgets support each 2.4 GHz plus five GHz transmitters to the very same accessibility point. The modulation structure utilised with 802.11a is OFDM, along with greater files costs in addition to minimizing results involving interference. Each region specifies the quantity of stations and frequencies the item permits with all the 5 various GHz band.
802.16
This is usually a metropolitan (MAN) wireless ordinary to deliver residence along with company clients seamless cell access from anywhere. The line of picture technological innovation specifies a distance involving all-around 27 mile after mile in addition to rates with upward for you to 120 Mbps. The place that will multipoint specification operates while in the 10-66 GHz range. There is definitely 802.16a specification having nylon uppers topologies and non-line involving picture having frequencies from your licensed and unlicensed 2 GHz along with 11 GHz group of musicians at a velocity connected with 70 Mbps. The crucial difficulty with just about any MAN setup using unlicensed frequencies can be interference through comparable devices.
802.11n
The fresh 802.11n the now necessary wireless standard okayed in 2009 defines with more speed information rates involving 300 - 1000 Mbps along with a thousand Mbps from gain access to position that will multi-level transition boosting throughput from clientele to reach position plus admittance point that will system switch. It works out both in this 2.4 GHz and also five GHz bands using useful brand-new effectiveness innovations just like several insight a number of result (MIMO) in addition to channel bonding.
Wireless Contention
Access factors are generally fundamentally some sort of a lesser amount of efficient link fashion shared mass media system which includes a chiseled send out domain. Contrast that which has a Cisco Ethernet switch who has 100/1000 Mbps bandwidth per vent in addition to send out segmentation along with VLANs. The move functions a a lot more powerful storage devices admittance contention system when compared with wireless access points. The instant community engages an older much less efficient service sense several access together with injury avoidance (CSMA/CA) progression to manage consumer entry on the network. The influence regarding CSMA/CA is usually amplified bandwidth usage, bundle loss along with bundle re-transmits using this type of shared media. In add-on you'll find the typical wireless reactions to this 2.4 GHz group of musicians disturbance and multipath indication lose colour in which occurs if the sign bends or is usually altered because of the setting up s tructure. From some sort of sensible opinion 15-25 cellular customers can easily connect having a single entry position grow older and also continue to keep fine performance. This certainly adjustments as a lot more video and higher bandwidth purposes are used. The 802.11n might essentially support all of those purchasers operating simulataneous live video tutorial streaming together with age 14 ones jogging hi-def movie streams.
Data Rate, Distance in addition to Frequency
So uncontrollable people understand there is absolutely no warp speed together with older wireless. Data rate (speed) in addition to effectiveness metrics decrease since the wireless purchasers move more through the access point. Beyond a typical connected with 50-60 feet, the speed lessens as well as latency, bundle damage and jitter increase. The the now necessary wireless multi-level web site questionnaire can determine exactly where and the amount of access things ought to always be started so every single cell (defined coverage area) features a sign energy with 54 Mbps. The insurance coverage area is often extended which has a more powerful directional antenna. For instance, these are rough graded distance, speed in addition to rate specifications house for the Cisco 1240AG entry point. Note the 802.11a long distance is usually fifty percent this of the 802.11g radio stations however this specific ranking seemed to be with a better 3.5 dBi antenna.
802.11a (5 GHz): 54 Mbps @ 60 foot - 80 ft using 3.5 dBi omnidirectional antenna
802.11g (2.4 GHz): 54 Mbps @ 80 ft - 100 ft using 2.2 dBi dipole antenna
As the info amount improves your own efficient multilevel range decreases. Clients that will want your steady greatest bandwidth will need to set up additional entry points per design. Increasing transmit electric power will actually minimize circle range from higher facts charges whilst boosting the actual selection with lower information rates for instance your case together with 802.11g entry points. The problem is actually with increased transmit power, the particular receiver empathy minimizes which has a progression called error vector magnitude. That doesn't apply at that cellular purchasers where by monitor power really should be established from maximum to get best results. The community duration or perhaps handheld greatest distance is just about 100 meters through client to access point, is actually Ethernet wired design 100 meters from gain access to place in order to switch. The campus design is usually lengthy with additional move - transition connectivity of course.
Wireless records prices specify highest throughput however that isn't really your functional value. Mixed conditions such as 802.11b and 802.11g could cut down throughput regarding each purchasers around the exact same multi-level segment. As stated the actual 802.11b in addition to 802.11g clients are similar value as well as can certainly companion with all the exact entry stage using the 2.4 GHz group of musicians spectrum. Throughput with regard to 802.11b is just about 6 Mbps however that may are different with antenna type, range from your accessibility place in addition to monitor power. Configure this obtain stage with 54 Mbps intended for 802.11g clients and also basic 11 Mbps to the 802.11b clients. That prevents this access point from operating at less in comparison with eleven Mbps. Some accessibility tips might operate together with double band 802.11a as well as 802.11g nonetheless there're separate logical systems as well as need to have individual instant i nternet site surveys. The 802.11a gain access to issue purposes the a few GHz rate band. As rate wavelength improves the community variety will decrease. The style and design along with 802.11a truck covers a reduced amount of way away likened having 802.11g in the same facts rates. The greater rate (5 GHz) signals do not traverse the creating system as speedy since lower frequencies.
These are usually some normal bandwidth throughput valuations and related cellular standards. From a new handy viewpoint almost all 24 options shouldn't get offered with all the 802.11h standard as well as 802.11a access items expected for you to sales channel overrun interference. Note the impact connected with mixed environment cellular gear such as 802.11b/g with similar multi-level and diminished throughput. This comes about also when you can find 802.11n gain access to points by using older access factors about the exact same network.
802.11b - half a dozen Mbps back button three channels
802.11g - twenty two Mbps x 3 or more channels
802.11b/g - 8 Mbps back button three or more channels
802.11a - 25 Mbps back button twenty one channels
802.11n - a hundred and fifty Mbps/300 Mbps x 21 years of age channels
Decreasing that transfer electrical power of an obtain stage will probably minimize route interference. The powerful network assortment is often extended using repeater accessibility points, increasing entry point transfer strength or perhaps altering that access stage position. Using a better gain antenna about the entry stage is surely an solution while well. Cisco access points possess a lot of options for deploying antennas along with better achieve plus sensitivity. Note you need to minimize this cable tv size of any kind of antenna. The more antenna cabling will attenuate this signals. Some locations control the uppermost level of access issue transfer energy setting.
RF Propagation
As mentioned mark attenuation is usually a whole lot worse with increased frequencies. There is actually however loads of environmental elements which distort, bend in addition to decrease sign strength. The end result is usually something labeled multipath fading exactly where an indication uses numerous routes to your destination. These are some examples.
� Diffraction - sign bending due to constructing framework angles
� Refraction - geographical aspects for instance humidity could potentially cause mark for you to bend
� Reflection - water, tumbler or almost any clean floor can jump a signal distorting and also remover it
� Absorption - buildings absorbing signal (trees)
� EMI disturbance - cordless phones, microwave ovens, power motors, bluetooth devices
Fade Margin is the amount of recipient awareness strength that is often decreased although preserving appropriate community performance. That is really a element with deployment of exterior wireless bridges using position to help stage topologies these as homes for a campus. Problems by using rain will attenuate signs in addition to figuring out the particular fade margin will probably prevent effectiveness issues. Polarization is the location from the radiated pattern from your antenna and also for a key need to go with using transmitting as well as acquiring antenna. The most often polarization combined with entry stage antenna is definitely linear. Antenna might transmit horizontal or a vertical polarized signal.
Improving Video through Wireless Performance
When discussing bandwidth prerequisites along with numerous video expert services it is vital to note which a instant circle will invariably require considerably far more bandwidth as compared to your small business LAN and also the house internet relationship to the similar video service. An example is usually high description dwell video internet when the particular wireless bandwidth essential is higher as opposed while using LAN or maybe home cable/DSL internet connection. The house internet association would certainly need 500 Kbps - a single Mbps. That seriously isn't a problem also to get household world wide web the place that the wire download rate is definitely an common 10 Mbps. The wireless multi-level with gain access to contention and also multipath remover troubles won't be when useful as well as would use a good bandwidth involving 5 various - eight Mbps. In addition, be aware which packet decline does impact video above wireless performance over latency an d jitter however all metrics can be improved with the next advised improvements.
1. Deploy the brand new 802.11n Access Point plus Client Adapters
The new 802.11n instant accessibility stage is actually scored at 300 Mbps considering the brand new element enhancement. That is 6x speedier as opposed to nearest 802.11g standard. Deploying 802.11n inside the a few GHz music group also , you have 21 years old non-overlapping options obtainable seeing that well. That will allow to get better info fees every insurance coverage area. The innovative enhancements include many reviews multiple output (MIMO), route bonding, MAC block acknowledgment, payload optimization plus unicasting and QOS prioritizing of traffic classes.
MIMO Explained
802.11n functions various input/output antennas about the access position as well as cellular client to add to data rates and minimize re-transmits and packet loss. The gain access to position along with clients can easily send simultaneous targeted traffic revenues increasing as much files as well as extending the circle selection (distance). The current most widely used Cisco 1250 AP makes use of what's called a 2T x 3R MIMO. That will be 2 transfer antenna to the obtain point and three or more receive antenna within the client. The most effective outcomes take place when almost all cellular clientele make use of 802.11n adapters as well as obtain points are usually most of 80.11n with no merged environment involving 802.11a/g accessibility points.
Channel Bonding
The technique of route bonding today enables incorporating with only two non-overlapping channels inside 5 various GHz piece in order to give files during 2x the standard files rate for your theoretical 300 Mbps. In training the common files rate have been screened at 180 Mbps and 140 Mbps for video tutorial streaming. That is usually really extraordinary weighed against 802.11g regular throughput with twenty two Mbps.
Payload Optimization
The aspect involving payload marketing or maybe bundle aggregation is absolutely settling far more data in each one bundle despatched resulting throughout more effective technique carry media.
MAC Block Acknowledgment
Previous obtain things needed that every MAC core MPDU supply was on their own recognized by using an ACK packet. The brand-new 802.11n standard currently utilizes just one hinder ACK to be able to acknowledge a number of MPDUs. This lessens the amount of method cost in addition to less bandwidth required.
Multicast to Unicast Traffic
Video above the now necessary wireless provides a selected trouble together with multicasting that the wired entire world will not have. Wireless obtain things tend not to support multicasting on the other hand 802.11n can now convert multicast to help unicast revenues per wireless client at core 2.
2. Network Design
The wireless gain access to items must always end up being powering a new 100 Mbps entire duplex switch port. The 802.11n entry things really should be connected to some sort of 1 Gbps or perhaps 10 Gbps switch port. Video end items ought to be coupled finer on the submitting coating and with a a lesser amount of chaotic line card. The ending point training video origin apparatus could be located in the system edge because well, then again a person should pick out some sort of swap having the many performance features and rather located in that facts center. Wireless several SSIDs should always often be defined for you to segment page views and also issued VLANs to complement a similar VLAN schema executed within the wired network.
Use your hierarchical pattern having any different wireless/wired deployments and also in which achievable spread out plus connect access items across multiple network changes as an alternative to an individual switch. Consider accomplishing some operation supervising on the multilevel to do away with mass media mismatches. For example a multi-level transition with a Gigabit vent that's uplinked to some swap using a 100 Mbps interface. As well WAN circuits tend to be chapter 13 this slowest link compared with the particular transition infrastructure.
�Have an effective cell network website customer survey carried out pertaining to each one piece in order to reduce mark overrun and optimise coverage.
�Deploy internal purchaser adapters instead of external USB style at your laptop with regard to very best performance.
�When deploying 802.11a/b/g access tips (mixed environment) having 802.11n gain access to points, this is more preferable for you to assign the 802.11n access details and clients into the 5 GHz group exactly where there is far more non-overlapping channels and also a smaller amount interference.
�Use almost all 802.11n entry points along with people exactly where possible rather then mixed ecosystem and at the least 2T x 3R x 2S spatial streams.
�Use additional accessibility points per protection community having 802.11n during 5 GHz with regard to increased facts rate, array (distance), variety of consumers and also multilevel availability.
�Deploy bigger extended array antennas to be able to raise the data price plus range.
�Clean up difficulties with virtually any sub-optimal routing on the network.
�Consider deploying the WLC 4400 WLAN controllers. This calls for a firmware up grade upon most of 1100 as well as 1200 string autonomous access points, nevertheless you will find advantages such as advanced RF direction features.
3. End that will End Quality of Service (QOS)
Any fine level of quality of service deployment need to consider each wired in addition to wireless QOS techniques for insuring end to end performance. The wired QOS was already discussed these with Shared Round Robin (SRR) and Weighted Round Robin (WRR) hardware queuing about switches. As very well there is Low Latency Queuing (LLQ) in addition to Class Based Weighted Fair Queuing (CBWFQ) integrated upon WAN routers. DSCP and also CoS bundle paying attention to can be used that will prioritize certain traffic forms for preferential queuing. Wireless now has Wireless Multimedia Extensions (WMM) that classifies targeted traffic together with 4 categories as outlined by targeted traffic type. These comprise voice, video, most effective effort along with background. This offers some sort of guaranteed service level regarding video tutorial traffic throughout periods with network congestion.
The part 2 information shape through the change provides a strong 802.1p industry the location where the course of provider (CoS) bits are usually set. The admittance place examines that will field as well as lists page views which includes a precise CoS establishing towards assigned queue. The words targeted traffic line could be the largest concern queue along with any kind of visitors queued there is serviced in advance of video tutorial and also data. Any instant people possibly not implementing VoIP will have movie prioritized first. Note in which despite the fact that queue 3 best hard work has a CoS connected with 0 that queue remains higher priority than background traffic. Cisco VideoStream program layer enhancement makes it possible for project of video traffic with a priority stream as outlined by some sort of VLAN as well as SSID assignment for preferential queuing.
Access Point Priority Queuing:
Queue 1: Voice Traffic CoS = 6,7
Queue 2: Video Traffic CoS = 4,5
Queue 3: Best Effort (Transactional Data) CoS = 0,3
Queue 4: Background Traffic (Email) CoS = 1,2
Call admission manage is usually a type of QOS of which limitations how many video times in order to avoid oversubscription from the goal line at the actual switches as well as routers. The us going for a gatekeeper support computer monitors the amount with video classes and denies any kind of more sessions determined by the particular bandwidth setting of the queue. The goal queue is definitely configured having more than enough bandwidth for just a unique number of sessions and virtually any demands for added classes tend to be denied in case of which exceeds this queue size.
4. Bandwidth
As mentioned, carrying out a effectiveness examination with the present multilevel will probably discover exactly where additional bandwidth is actually needed. The company WAN is the most frequent source of problems with bandwidth. The occurrance and also less costly involving Metro Ethernet Gigabit circuits right now allow it to become fantastic opportunity release it around the provider network.
Shaun Hummel may be the writer of Network Planning and Design Guide and also offering Networking Books, eBooks, Certifications, Articles and Design Tools.
Copyright 2011 Shaun Hummel All Rights Reserved
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