Benefits & Shortcomings1

Community Wi-Fi

1 The planned Greenspring PON upgrade will provide wireless networking for all Residents, Staff, and guests however it will NOT provide WIRED Internet service.

Wireless Local Area Network (WLAN)

Wireless Router Modem

Coax Outlet

A Wireless Router forwards data packets between devices, creating a network. It also provides access to WIRED Internet, currently at Greenspring through a cable Modem. Connection to the devices is made wirelessly, via radio waves. It can function in a wireless-only LAN (WLAN), or in a mixed wired/wireless network, depending on the model. A Wired Router connects with wires only and performs the same functions. The Router also serves as a firewall accessible only to its owner.

Options currently available: 1) A Directly wired connection to a single computer 2) A wired Router connecting to multiple devices 3) A wireless Router connecting to all devices 4) A mix of wire and wireless

Note that when connected a device becomes a “client” of the WiFi Router

What is a PONPassive Optic Network

What is PON?

• Passive Optical Network

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An Optical Network Terminal (ONT) will be provided for each apartment located under the shelf outside your apartment door. It will be fed with fiber from the PON and will convert the optical data from the PON to the electrical signals that enter your apartment through the existing twisted pair and coax cables AND convert the return electrical signals from your apartment back to optical for delivery to the PON. Wi-Fi transmitters will be located in the ceilings of the hallways.

Hallway Access Point

<----To Other Apartments To Other Apartments ---->

The Community Wi-Fi planned for Greenspring will provide access points in the hallway ceilings each serving several apartments. All of the Resident's devices must be Wi-Fi capable and can only access the Internet via the Hallway Access Point. No Wired Internet will be available. Virtual LAN's will provide a level of security and allow devices to exchange data.

Walls

There will be no options available with the planned Community Wi-Fi

CAUTION:Do not use an Ethernet cable to connect the extender to a router. If you do so, the extender does not work because it is designed to use only a wireless connection to the router.

When to Use Your ExtenderNETGEAR recommends that you connect to the extender only when your home network connection is poor. Because data traffic routed through the extender is inherently slower than traffic routed directly from the network, the computer should stay on the network if the connection is good enough. NETGEAR recommends that you connect through the extender network only when the computer is in a “dead zone” where connection from the network is very poor or non-existent.

NETGEAR Range Extender WN2500RP

Benefits of Community Wi-Fi

• Wireless networking for all Residents, Staff, and guests

• The simplicity may stimulate more Computer and Tablet use by novices & newbies

• Some Users may have a useful experience from the Community Wi-Fi for low to medium bandwidth activities such as web browsing and checking email

The Shortcomings• No device,computers, printers etc. can connect to the

network without Wi-Fi capability

• Routers, wired or wireless, are unusable and may be replaced by wireless VLAN (Virtual Local Area Network)

• The security of a VLAN is controlled by the network administrator and therefore Residents will not have exclusive control of their network security

• Over Wi-Fi, it is unlikely that the promised high levels of availability & speed will be realized. Over Wi-Fi, Internet service may not even be as fast or as reliable as that currently available to us.

• A Community Wi-Fi isn’t dependable for consistent multiple streams of HD IP video(e.g. NetFlix and Hulu). VoIP and Skype may be erratic and large network downloads may be unpredictable and slow.

The Benefits of Wire• Networking, wired or wireless, can be set up and managed by

the resident of each apartment allowing them to isolate their devices with a secure firewall under their exclusive control

• The fast changing Wi-Fi technology will be managed by the Resident leaving the campus wide Wi-Fi network independent and still available to all (residents and visitors)

• Provides options: the simplicity of Community Wi-Fi or the capacity of wired Internet to access the full speed and potential of the Internet or both

• By connecting their client devices to their own network, high bandwidth users relieve the burden on the Community Wi-Fi.

• Avoids the cost and complexity of VLANs and mitigates the shortcomings of the planned Community Wi-Fi

• Wired Internet benefits all Residents, those who chose Wi-Fi, the technophiles current and future and those who just want ‘Zero TV’ homes and NETFLIX.

WHY NOT WIRE?

• New Ethernet cabling could be installed in the apartments but if too costly, why not connect each apartment to its ONT with Multimedia over Coax technology (MoCA) allowing use of the existing coax cable to deliver Ethernet as well as TV

• The PON can thus deliver both Internet and TV service to the existing coax in the apartment. With MoCA technology we would have high speed Internet access on every coax outlet. Cox and Verizon do this for their customers

★ The Question is WHY NOT for us

Wi-Fi Limiting Factors

• Limitations of the Wi-Fi protocols

• The number and types of wireless clients* in an area**

• The infrastructure in an area(i.e., the number and layout of wireless access points, the building structure and walls to pass through)

• The level of interference in an area

• An individual client's wireless hardware and software

* In a Wi-Fi network, a "client" is simply a device that joins the network, like a computer or a wireless printer, Smart TV, a tablet device, an iPhone etc.** The term ‘area’ as used here is the sector covered by a single access point (e.g.wireless router) providing access to the Internet and interconnection of its’ client devices

Wi-Fi ProtocolAre Rules governing the exchange or transmission of data between devices

• For example: Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) is a media access control protocol. It works as follows:

• Wi-Fi networks are shared media and the access point and the computing devices all vie for use of the same channel.

• Wi-Fi systems are half duplex where all stations transmit and receive on the same radio channel. (e.g. walkie talkie protocol – push to talk – say “Over” when your ready to listen)

• The problem this creates in a radio system is that a station cannot hear while it is sending, and hence cannot detect a collision*.

• The developers of the 802.11 specifications came up with a collision avoidance mechanism where a Wi-Fi station will transmit only if it thinks the channel is clear.

• All transmissions are acknowledged, so if a station does not receive an acknowledgement, it assumes a collision occurred and retries after a random waiting interval.

• The incidence of collisions will increase as the traffic increases or in situations where mobile stations cannot hear each other. Data transfer speed will slow down.

*A network collision occurs when more than one device attempts to send a packet on a network segment at the same time.

The Wireless Standards

802.11b/g (2.4 GHz) and 802.11n (5 GHz)

• A single access point can serve approximately twenty-five 802.11b/g (2.4 GHz) clients* and forty 802.11n (5 GHz) clients*.

• A maximum of three 802.11b/g (2.4 GHz) radios can be installed in close proximity. More than three can decrease network performance.

• More bandwidth available with 802.11n in 5 GHz, so more clients can be supported However: 5 GHz signals have shorter range and are absorbed more readily by walls and other solid objects. Also some clients may not be 802.11n capable

• Types of clients affect the user experience For example, one 802.11b client will slow down all 802.11g and 802.11n clients using 2.4 GHz frequencies

• Overhead from network protocol data that Wi-Fi connections must exchange for security and reliability purposes reduces actual speed. Rule of thumb for actual speed capability of Wi-Fi is half of the peak data rate. So if the device says it can do “54 Mbps” you may get 27

• Half-speed rule applies to optimal connections: good signal strength, no interference. With poor connection speed will be even lower

Wi-Fi, A Shared Medium• Signal strength and "connection speed" do not reflect what a

client's Wi-Fi experience will be like. • Clients in an access area share the finite bandwidth resources of a

single router -- Increase the number of clients and the network becomes slower for all.

• An 802.11g access point can achieve about 27 Mbps at best. Shared by 10 clients, each gets a modest 2.7 Mbps. If shared by 25 clients, around 1 Mbps.

• 802.11n improves this a bit. Advertised speed of 150 Mbps becomes 70 Mbps. But advantage is lost because of the shorter range and absorption of the 5 GHz frequency by walls.(Particularly Greenspring walls)

• There is no fairness mechanism built into the Wi-Fi protocols, so it is possible for few clients to consume most of the available bandwidth in an area, so that other clients will experience slow performance even with a strong signal and high connection rate.

Other Factors

• Interference, plays major role in quality of user experience.

• Many types of devices use the radio frequencies used in Wi-Fi including cordless phones, wireless headsets, wireless microphones, microwaves, etc. can cause interference. DAS transmitters may also be a source of interference.

• The presence of interference can result in a client showing connection but unable to perform network operations, slowing down network operations, or completely disconnecting the client from the wireless infrastructure.

• Wi-Fi connection speed varies with distance. When you join a Wi-Fi network and the access point is nearby, your device will typically connect at its maximum speed. Move away from the access point, connection speed will drop and can become very slow. A feature of Wi-Fi called dynamic rate scaling causes this phenomenon.

Will increasing a Wi-Fi access point power extend its range?

The Answer is "No" • A notebook computer or tablet using built-in Wi-Fi adapter

transmits with a power level of 100 mW (or less). If an access point puts out more than 100 mW signal then the access point will be capable of transmitting to a distance from which the notebook computer can't transmit back.

• The Wi-Fi client (the notebook computer) "hears" the access point. Unfortunately, the access point has no way to "hear" the client to acknowledge receipt of a packet.

• The client connection fails, even though the signal level seen from the access point may be stronger than other, lower power, access points.

• The output power from an access point should never exceed the output power from the clients that are attaching to it.

The Reply to Why Not

Mr. Raymond:The primary answer is one of cost.  An approximate charge of $300 per additional drop has been estimated by our vendors through Hans Keller.  Knowing our number of drops to be 1,686, which includes 1,404 Independent Living apartments and 282 Assisted Living and Skilled Nursing units, the additional cost would be $505,800.A second answer is one of service where entrance to an apartment would be required to source possible issues with the connections.Greenspring’s Board of Directors, advised by management and with guidance and assistance from Erickson’s IT department, has made a decision to move ahead with wireless internet.  We appreciate your interest and input, but there are no anticipated deviations from that plan.Thank you!GSV Director of Finance

My Response• The Erickson/Greenspring plan is to use existing coax in the apartment to

provide TV. That requires a “drop” so you can use that “drop” to also provide Internet with a cable modem as we have now or with the MoCA technology. If we want wired Internet we would purchase and maintain our own modems, adapters and routers as needed as we do now.

• It is unlikely that sharing the coax would cost nearly the $300 per apartment but even if it did and it totaled and additional $500,000 for the multi-million dollar DAS/PON project it is worth it. It allow access to the full potential of the Internet that Wi-Fi can not.

• Rates will be raised by $50/m, add $5 and the “drop” cost would be paid off in less than 5 years.

• Wi-Fi will have many problems and they all will be manifested by the connected client devices located in the apartments. You cannot avoid entering apartments to resolve issues that may or may not be with the network Access Point in the hallway.

• Erickson/Greenspring is making a very big mistake to rely solely on Community WiFi. It will cause more grief than wire ever will.

An IEEE initiative called EPON protocol-over-coax (EPoC) has the goal of enabling cable companies initially to offer high-speed services over coax—and eventually boost residential broadband speeds

Take it or Leave itMr. Raymond:

We thank you for your continued input, and in that light, let us be very clear…if there were any concerns on the part of Erickson Living Management LLC or Greenspring management we would never have recommended this solution to the Board of Directors, and if the Board of Directors had any concerns, they would never have approved the project as designed.  We do not have any concerns about the privacy of any information that will be transmitted over this wireless network.  We do not have any concerns on how the network will be managed and supported, nor do we have any concerns about how our residents will be supported.  This is the solution the community will implement. Please feel free to continue to comment as you deem appropriate, but understand that we will have to agree to disagree about any and all of the concerns you continue to raise.  This solution will work, and is in the best interest of the community…residents, staff and visitors.  That is our firm conviction and will remain so through the entire life of this project, and beyond. Thank you.Director of Finance

Information from Hans Keller V.P. of Information Technology for Erickson Living,

Received May 8, 2013

• Hans: Will not provide specific Service Level Agreements such as those offered by Verizon or other carriers in regards to guaranteed bandwidth. This is not to be construed to mean that we will not be providing equal or better service, but that we are simply not measuring the quality of the service by bandwidth alone.My Comment: No guaranteed speeds?? What is the measure of service?

• Hans: Providing 680 access points (AP) for the community. Worst case scenario, one AP will support four Resident units.My Comment: Expect WiFi co-channel interference. Given the number of access points for the community, my building, (Walden Court) will have 6 to 8 AP's on each floor and 30 to 40 AP's in the building. Given that 802.11 protocol allows for only three non overlapping channels in the 2.4 GHz band mode how can you possible prevent serious co-channel interference?

• Hans: The service that we will be providing WILL ensure that our residents can enjoy high definition streaming services.My Comment: In my judgement this is unlikely for many reasons.

• Hans: Each AP will be connected back to the network with a 1 GB connection.  If we figure that each unit has 10 devices they are connecting to the AP, that is 40 devices leveraging this 1 GB connection.My Comment: What sense does it make to provide a 1 Gigabit connection to a WiFi access point that can't delivery any where near that. It is like connecting a fire hose to a garden hose. At best 802.11bg can deliver 27 Mbps and the 5 GHz 802.11an will not get through the walls and even if it did it can deliver no where near a Gigabit — maybe 150 Mbps. Divide those numbers by 40 and we are well below our current speed.

• Hans: Regarding security over the wireless network, we are still in the process of finalizing exactly how this will be provisioned.

Multimedia over Coax Alliance (MoCA)Internet Protocol over Coax

Offers reliable, high-speed, full-bandwidth, quality access to HD IP video streams, Ethernet to TV, content such as NetFlix or Hulu

802.11 Protocol

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RayNet Signal

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RayNet Signal

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Wireless  Performance  in  General  (Not  all  Mbps  are  Equal):Brian  Verenkoff,  Director  of  Marke2ng  and  Business  Development,  Buffalo  TechnologyOne  of  the  most  common  confusions  surrounding  wireless  networking  devices  is  performance.  Historically,  interface    speeds  with  computer  related  technologies  have  been  highly  accurate.  For  example,  a  100  Mbps  wired  Ethernet  connecJon  is  capable  of  regularly  producing  100  Mbps  data  transfer  speeds.Wireless  networking  equipment  involves  much  greater  complexiJes.  Unlike  a  wired  Ethernet  connecJon,  wireless  communicaJons  cannot  be  ensured.  When  a  wireless  device  sends  data  to  another  wireless  device,  the  sending  device  cannot  determine  if  the  receiving  device  acquired  the  message  unless  the  receiving  device  posiJvely  confirms  it.  This  is  called  an  acknowledgement.  While  many  issues  can  prevent  two  wireless  devices  from  successfully  communicaJng,  here  are  a  few:•   Devices  are  too  far  away  from  each  other  •   Another  device  was  transmiQng  at  the  same  Jme  •   An  external  interference  source  caused  excessive  interference,  etc.  

To  work  around  these  issues,  a  wireless  device  sends  data  in  small  chunks  with  addiJonal  verificaJon  data  (checksum/CRC).  The  client  receives  the  small  chunk  and  

compares  it  with  the  verificaJon  data.  If  the  verificaJon  is  successful,  the  receiving  device  then  sends  a  message  (ACK)  back  to  the  original  sending  device  informing  it  that  the  data  was  received  successfully.  Once  that  message  is  received,  the  sending  device  begins  sending  its  next  chunk  of  data.  On  top  of  this,  only  one  wireless  networking  device  in  a  network  will  communicate  at  any  given  Jme  so  there  is  addiJonal  technology  and  overhead  to  make  sure  that  devices  are  only  communicaJng  in  turn.  These  advanced  and  tedious  methods  of  sending  data  require  a  lot  of  overhead.  Using  802.11g  as  an  example,  it  offers  performance  of  up  to  54  Mbps.  Of  the  54  Mbps,  roughly  half  of  the  wireless  data  being  sent  is  overhead  to  support  transmission.  This  makes  actual  data  throughput  roughly  half  of  the  maximum,  or  around  25-­‐27  Mbps  of  actual,  usable  data  throughput.  Finally,  the  rated  performance  (e.g.  54  Mbps)  is  assuming  a  link  integrity  that  is  pre^y  close  to  perfect.  As  a  signal  weakens  or  interference  is  increased,  this  speed  is  greatly  affected.  Wireless  networking  technologies  are  capable  of  transmiQng  very  far  given  their  power  output.  To  achieve  long  range,  the  devices  negoJate  slower  rates.  The  signal  strength  and  negoJated  speed  is  o_en  displayed  to  users  in  the  form  of  signal  bars  and/or  link  speed.  The  reported  link  speed  always  considers  the  addiJonal  overhead  and  does  not  indicate  the  speed  at  which  data  will  actually  be  transmi^ed.

Wi-Fi networks support certain maximum connection speeds (data rates) depending on their configuration. However, the maximum speed of a Wi-Fi connection can automatically change over time. Answer: This behavior is called dynamic rate scaling, a design feature of Wi-Fi networks. When a device initially connects to a network via Wi-Fi, its rated speed is calculated according to the current signal quality of the connection. The rated connection speed then automatically changes over time if necessary to maintain a reliable link between the devices. Wi-Fi dynamic rate scaling extends the range at which wireless devices can connect to each other in return for lower network performance at the longer distances.802.11b/g/n Dynamic Rate ScalingAn 802.11g Wi-Fi device in close proximity to a network router will often connect at 54 Mbps. This maximum data rate is displayed the device's wireless configuration screens. Other 802.11g devices located further away from the router, or with obstructions in between, may connect at lower rates. As these devices move further away from the router, their rated connection speeds eventually get reduced by the scaling algorithm, while devices that move closer can have speed ratings increased (up to the maximum of 54 Mbps.

Wi-Fi devices have their rates scaled in pre-defined increments. For 802.11g, the defined ratings are (from highest to lowest)

54 Mbps 48 Mbps 36 Mbps 24 Mbps 18 Mbps 12 Mbps 9 Mbps 6 MbpsSimilarly, old 802.11b devices supported the following ratings

11 Mbps 5.5 Mbps 2 Mbps 1 MbpsControlling Dynamic Rate ScalingFactors that determine which data rate is dynamically chosen for a Wi-Fi device at any given time are:

•" Distance between the device and other Wi-Fi communication endpoints

•" Radio interference in the path of the Wi-Fi device

•" Physical obstructions in the path of the Wi-Fi device, that also interfere with signal quality

•" The power of the device's Wi-Fi radio transmitter/receiver

Wi-Fi home network equipment always utilizes rate scaling; a home network administrator cannot disable this feature.

Why Do Wi-Fi Connection Speeds Keep Changing?