Oliver Scheer

Senior Technical Evangelist

Microsoft Deutschland

http://the-oliver.com

Network Communication in Windows Phone 8

Agenda

Networking for Windows Phone

WebClient

HttpWebRequest

Sockets

Web Services and OData

Simulation Dashboard

Data Compression

Networking on Windows Phone

Networking on Windows Phone

• Support for networking features

•Windows Communication Foundation (WCF)•HttpWebRequest•WebClient•Sockets•Full HTTP header access on requests•NTLM authentication

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New Features in Windows Phone 8

• Two different Networking APIs• System.Net – Windows Phone 7.1 API, upgraded with new features•Windows.Networking.Sockets – WinRT API adapted for Windows Phone

• Support for IPV6• Support for the 128-bit addressing system added to System.Net.Sockets and

also is supported in Windows.Networking.Sockets

•NTLM and Kerberos authentication support

• Incoming Sockets• Listener sockets supported in both System.Net and in Windows.Networking

•Winsock support•Winsock supported for native development

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Networking APIs Platform Availability

API WP7.1 WP8 W8

System.Net.WebClient

System.Net.HttpWebRequest

System.Net.Http.HttpClient

Windows.Web.Syndication.SyndicationClient

Windows.Web.AtomPub.AtomPubClient

ASMX Web Services

WCF Services

OData Services 04/12/20236

Async support in WP8 Networking APIs

• C# 5.0 includes the async and await keywords to ease writing of asynchronous

code

• In desktop .NET 4.5, and in Windows 8 .NET for Windows Store Apps, new Task-

based methods allow networking calls as an asynchronous operation using a

Task object•HttpClient API•WebClient.DownloadStringTaskAsync(), DownloadFileTaskAsync(),

UploadStringTaskAsync() etc•HttpWebRequest.GetResponseAsync()

• These methods are not supported on Windows Phone 8• Task-based networking using WebClient and HttpWebRequest still possible

using TaskFactory.FromAsync() and extension methods • Coming up later…

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Connecting the Emulator to Local Services

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• In Windows Phone 7.x, the emulator shared the networking of the Host PC• You could host services on your PC and access them from your code using

http://localhost...

• In Windows Phone 8, the emulator is a Virtual machine running under Hyper-V• You cannot access services on your PC using http://localhost...• You must use the correct host name or raw IP address of your host PC in

URIs

Windows Phone 8 Emulator and localhost

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• If you host your web sites or services in IIS, you must open your firewall for

incoming HTTP requests

Configuring Web Sites Running in Local IIS 8Firewall

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• If your service is a WCF service, you must also ensure that HTTP Activation is

checked in Turn Windows features on or off

Configuring Web Sites Running in Local IIS 8WCF Service Activation

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• Create your website or web service in Visual

Studio 2012

• Run it and it is configured to run in

localhost:port

Configuring Sites Running in IIS ExpressSTEP 1: Create Your Website or Web service

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• Remove your website (don’t delete!) from the Visual Studio 2012 solution

• Edit the file C:\Users\yourUsername\Documents\IISExpress\config\

applicationhost.config• Find the <sites> section• Find the entry for the website or service you just created• Change

<binding protocol="http" bindingInformation="*:nnnn:localhost" />

to

<binding protocol="http" bindingInformation="*:nnnn:YourPCName" />• Save changes

• Use ‘Add Existing Website’ to add the website folder back into your solution

Configuring Sites Running in IIS ExpressSTEP 2: Modify Config to Run on a URI Using Your PC Name

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• From a Command Prompt (Run as Administrator), open the port in the Firewall: netsh advfirewall firewall add rule name="IIS Express (non-SSL)"

action=allow

protocol=TCP dir=in localport=nnnn

• Also run the following at the command prompt:

netsh http add urlacl url=http://yourPC:nnnn/ user=everyone• Substitute yourPC with the host name of your Host PC• Substitute 8080 for the port where your service is running

• Run it and access from your desktop browser – Now it is hosted at

YourPCName:port

Useful References:• How to: Specify a Port for the Development Server

http://msdn.microsoft.com/en-us/library/ms178109(v=VS.100).aspx

Configuring Sites Running in IIS ExpressSTEP 3: Open Port in the Firewall and Register URL

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WebClient

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Simple Http Operations – WebClient

using System.Net;...

WebClient client;

// Constructor public MainPage() { ... client = new WebClient(); client.DownloadStringCompleted += client_DownloadStringCompleted; }

void client_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e) { this.downloadedText = e.Result; }

private void loadButton_Click(object sender, RoutedEventArgs e) { client.DownloadStringAsync(new Uri("http://MyServer/ServicesApplication/rssdump.xml")); }

•No Task-based async methods have been added to WebClient

• Async operation possible using custom extension methods, allowing usage

such as:

WebClient using async/await

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using System.Net;using System.Threading.Tasks;...

private async void loadButton_Click(object sender, RoutedEventArgs e) { var client = new WebClient(); string response = await client.DownloadStringTaskAsync(new Uri("http://MyServer/ServicesApplication/rssdump.xml")); this.downloadedText = response; }

Demo 1: Simple HTTP Networking with WebClient

More Control – HttpWebRequest

private void PhoneApplicationPage_Loaded(object sender, RoutedEventArgs e){ var request = HttpWebRequest.Create("http://myServer:15500/NorthwindDataService.svc/Suppliers") as HttpWebRequest; request.Accept = "application/json;odata=verbose"; // Must pass the HttpWebRequest object in the state attached to this call // Begin the request… request.BeginGetResponse(new AsyncCallback(GotResponse), request);} 

• HttpWebRequest is a lower level API that allows access to the request and response streams

• The state object passed in the BeginGetResponse call must be the initiating HttpWebRequest object, or a custom state object containing the HttpWebRequest

HttpWebRequest – Response Handling private void GotResponse(IAsyncResult asynchronousResult) { try { string data; // State of request is asynchronous HttpWebRequest myHttpWebRequest = (HttpWebRequest)asynchronousResult.AsyncState; ; using (HttpWebResponse response = (HttpWebResponse)myHttpWebRequest.EndGetResponse(asynchronousResult)) { // Read the response into a Stream object. System.IO.Stream responseStream = response.GetResponseStream(); using (var reader = new System.IO.StreamReader(responseStream)) { data = reader.ReadToEnd(); } responseStream.Close(); }

// Callback occurs on a background thread, so use Dispatcher to marshal back to the UI thread this.Dispatcher.BeginInvoke(() => { MessageBox.Show("Received payload of " + data.Length + " characters"); } ); } catch (Exception e) ... }  

HttpWebRequest – Error Handling private void GotResponse(IAsyncResult asynchronousResult) { try { // Handle the Response ... } catch (Exception e) { var we = e.InnerException as WebException; if (we != null) { var resp = we.Response as HttpWebResponse; var code = resp.StatusCode; this.Dispatcher.BeginInvoke(() => { MessageBox.Show("RespCallback Exception raised! Message:" + we.Message + "HTTP Status: " + we.Status); }); } else throw; } }  

HttpWebRequest – Using TPL Patternprivate async void PhoneApplicationPage_Loaded(object sender, RoutedEventArgs e){ var request = HttpWebRequest.Create("http://yourPC:15500/NorthwindDataService.svc/Suppliers") as HttpWebRequest; request.Accept = "application/json;odata=verbose";

// Use the Task Parallel Library pattern var factory = new TaskFactory(); var task = factory.FromAsync<WebResponse>(request.BeginGetResponse, request.EndGetResponse, null);

try { var response = await task;

// Read the response into a Stream object. System.IO.Stream responseStream = response.GetResponseStream(); string data; using (var reader = new System.IO.StreamReader(responseStream)) { data = reader.ReadToEnd(); } responseStream.Close();

MessageBox.Show("Received payload of " + data.Length + " characters"); } catch (Exception ex) ...

HttpWebRequest (TPL) – Error Handling private async void PhoneApplicationPage_Loaded(object sender, RoutedEventArgs e) { try { // Make the call and handle the Response ... } catch (Exception e) { var we = e.InnerException as WebException; if (we != null) { var resp = we.Response as HttpWebResponse; var code = resp.StatusCode; MessageBox.Show("RespCallback Exception raised! Message:" + we.Message + "HTTP Status: " + we.Status); } else throw e; } }  

Demo 2: HttpWebRequest

Sockets

Sockets Support in Windows Phone OS 8.0

• TCP• Connection-oriented• Reliable Communication

•UDP Unicast, UDP Multicast• Connectionless•Not Reliable

•New Features in 8.0!• IPV6 support• Listener Sockets

Web Services

WCF/ASMX Services

• Can ‘Add Reference’ from

Windows Phone projects to

automatically generate proxy

classes• ASMX should ‘just work’•WCF requires that you use

basicHttpBinding

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RESTful Web Services

Building them

• Rather than building “walled gardens,” data should be published in a way that

allows it to reach the broadest range of mobile clients

•Old-style ASMX SOAP 1.1 Web Services using ASP.NET or Windows

Communication Foundation (WCF) require clients to implement SOAP protocol

•With Windows Phone 7 and Silverlight, we use WCF with BasicHttpBinding both

on-premise and as a Web Role in Windows Azure to publish our data from local

and cloud-based data sources like SQL Azure

• Recommend using lightweight REST + JSON Web Services that are better

optimized for high-latency, slow, intermittent wireless data connections

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WCF Data Services: OData

•WCF Data Services provide an extensible

tool for publishing data using a REST-based

interface • Publishes and consumes data using the OData

web protocol (http://www.odata.org)• Formatted in XML or JSON

•WCF Data Services Client Library

(DataServicesClient) is a separate

download from

NuGet• Adds ‘Add Service Reference’ for OData V3

Services

Generate Client Proxy

• In most cases, Add Service Reference will just work

• Alternatively, open a command prompt as administrator and navigate to

C:\Program Files (x86)\Microsoft WCF Data Services\5.0\tools\Phone

• Run this command

DataSvcutil_WindowsPhone.exe /uri:http://odata.netflix.com/v2/Catalog/

/DataServiceCollection /Version:1.0/out:netflixClientTypes

• Add generated file to your project

Fetching Data

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public partial class NorthwindModel { NorthwindEntities context; private DataServiceCollection<Customer> customers;

private override void LoadData() { context = new NorthwindEntities(new Uri("http://services.odata.org/V3/Northwind/Northwind.svc/")); // Initialize the context and the binding collection customers = new DataServiceCollection<Customer>(context);

// Define a LINQ query that returns all customers. var query = from cust in context.Customers select cust;

// Register for the LoadCompleted event. customers.LoadCompleted += new EventHandler<LoadCompletedEventArgs>(customers_LoadCompleted);

// Load the customers feed by executing the LINQ query. customers.LoadAsync(query); } ...

Fetching Data - LoadCompleted

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...

void customers_LoadCompleted(object sender, LoadCompletedEventArgs e) { if (e.Error == null) { // Handling for a paged data feed. if (customers.Continuation != null) { // Automatically load the next page. customers.LoadNextPartialSetAsync(); } else { foreach (Customer c in customers) { //Add each customer to our View Model collection App.ViewModel.Customers.Add(new CustomerViewModel(){SelectedCustomer = c}); } } } else { MessageBox.Show(string.Format("An error has occurred: {0}", e.Error.Message)); } }

Demo 3: OData Services

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Network Information and Efficiency

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Network Awareness

Making Decisions based on Data Connections

•Mobile apps shouldn’t diminish the user experience by trying to send or receive

data in the absence of network connectivity

•Mobile apps should be intelligent about performing heavy data transfers or

lightweight remote method calls only when the appropriate data connection is

available

•With Windows Phone, we use the NetworkInterfaceType object to detect

network type and speed and the NetworkChange object to fire events when the

network

state changes

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NetworkInformation in Windows Phone 8.0

• In Microsoft.Phone.Net.NetworkInformation namespace:• Determine the Network Operator:

• DeviceNetworkInformation.CellularMobileOperator• Determine the Network Capabilities:

• DeviceNetworkInformation.IsNetworkAvailable• DeviceNetworkInformation.IsCellularDataEnabled• DeviceNetworkInformation.IsCellularDataRoamingEnabled• DeviceNetworkInformation.IsWiFiEnabled

• In Windows.Networking.Connectivity namespace:• Get Information about the current internet connection

• NetworkInformation.GetInternetConnectionProfile• Get Information about the NetworkAdapter objects that are currently connected to a network

• NetworkInformation.GetLanIdentifiers

Determining the Current Internet Connection Type

private const int IANA_INTERFACE_TYPE_OTHER = 1;

private const int IANA_INTERFACE_TYPE_ETHERNET = 6;

private const int IANA_INTERFACE_TYPE_PPP = 23;

private const int IANA_INTERFACE_TYPE_WIFI = 71;

...

string network = string.Empty;

// Get current Internet Connection Profile.

ConnectionProfile internetConnectionProfile =

Windows.Networking.Connectivity.NetworkInformation.GetInternetConnectionProfile();

switch (internetConnectionProfile.NetworkAdapter.IanaInterfaceType)

{

case IANA_INTERFACE_TYPE_OTHER:

cost += "Network: Other"; break;

case IANA_INTERFACE_TYPE_ETHERNET:

cost += "Network: Ethernet"; break;

case IANA_INTERFACE_TYPE_WIFI:

cost += "Network: Wifi\r\n"; break;

default:

cost += "Network: Unknown\r\n"; break;

}

Tips for Network Efficiency

•Mobile devices are often connected to poor quality network connections

• Best chance of success in network data transfers achieved by• Keep data volumes as small as possible•Use the most compact data serialization available (If you can, use JSON

instead of XML)• Avoid large data transfers

• Avoid transferring redundant data

•Design your protocol to only transfer precisely the data you need and no more

Demo 4: Wire Serialization

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Wire Serialization Affects Payroll Size

• Simple test case: download

30 data records

• Each record just 12 fields

•Measured bytes to transfer

Wire Serialization Format

Size in Bytes

ODATA XML 73786

ODATA JSON 34030

REST + JSON 15540

REST + JSON GZip 8680

Implementing Compression on Windows Phone

•Windows Phone does not support System.IO.Compression.GZipStream•Use third-party solutions instead• SharpZipLib is a popular C# compression library (http://sharpziplib.com/) – on

NuGet• SharpCompress is another (http://sharpcompress.codeplex.com/)

•On Windows Phone OS 7.1, get GZipWebClient from NuGet• Replaces WebClient, but adds support for compression•Uses SharpZipLib internally•NuGet release for Windows Phone 8 not yet available (as of October 2012)•Until updated library released on NuGet, source is available online

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HttpWebRequest – With Compression var request = HttpWebRequest.Create("http://yourPC:15500/NorthwindDataService.svc/Suppliers") as HttpWebRequest; request.Accept = "application/json;odata=verbose"; request.Headers["Accept_Encoding"] = "gzip";

// Use the Task Parallel Library pattern var factory = new TaskFactory(); var task = factory.FromAsync<WebResponse>(request.BeginGetResponse, request.EndGetResponse, null);

var response = await task;

// Read the response into a Stream object. System.IO.Stream responseStream = response.GetResponseStream(); string data; var stream = new GZipInputStream(response.GetResponseStream()); using (var reader = new System.IO.StreamReader(stream)) { data = reader.ReadToEnd(); } responseStream.Close();

Compression with OData Client Library private void EnableGZipResponses(DataServiceContext ctx)

{

ctx.WritingRequest += new EventHandler<ReadingWritingHttpMessageEventArgs>(

(_, args) =>

{

args.Headers["Accept-Encoding"] = "gzip";

} );

ctx.ReadingResponse += new EventHandler<ReadingWritingHttpMessageEventArgs>(

(_, args) =>

{

if (args.Headers.ContainsKey("Content-Encoding") &&

args.Headers["Content-Encoding"].Contains("gzip"))

{

args.Content = new GZipStream(args.Content);

}

} );

}

• Reference: http://blogs.msdn.com/b/astoriateam/archive/2011/10/04/odata-compression-in-windows-phone-7-5-mango.aspx

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Demo 5: Compression

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Data Sense

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• The Data Sense feature allows a user to specify the limits of their data plans and monitors

their usage

• Your app can use the information provided by the Data Sense APIs to change data usage

behavior• Reduce data usage when the user is close to their data limits• Discontinue data usage when the user is over their limit• Or to postpone tasks that transfer data until a Wi-Fi connection is available

• Data Sense is a feature that Network Operators optionally support• Provide a Data Sense app and Tiles to allow users to enter their data limits• Routes data via a proxy server in order to monitor data usage

• If Data Sense is not enabled, you can still use the APIs to determine if the user is

connected to WiFi or is roaming, but you cannot determine the users data limits

Data Sense API

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•If on WiFi, no need to limit data usage

1. Get the Network Type from the

ConnectionProfile by calling

NetworkInformation.GetInternetConnectionCli

ent •Returns Unknown, Unrestricted, Fixed or Variable: If Unrestricted, no need to limit data usage

2. Get the NetworkCostType by calling

ConnectionProfile.GetConnectionCost

•If any are true, your app can reduce or eliminate data usage

3. Get the ApproachingDataLimit, OverDataLimit and Roaming

properties of the ConnectionProfile

Using the Data Sense APIs

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Responsible Data Usage in a Data Sense-Aware App NetworkCostType ConnectionCost Responsible data usage Examples

Unrestricted Not applicable. No restrictions.

Stream high-definition video.Download high-resolution pictures.Retrieve email attachments.

Fixed or Variable

All three of the following properties are false. •ApproachingDataLimit •OverDataLimit•Roaming

No restrictions.

Stream high-definition video.Download high-resolution pictures.Retrieve email attachments.

Fixed or VariableorUnknown

ApproachingDataLimit is true, when NetworkCostType is Fixed or Variable.

Not applicable when NetworkCostType is Unknown.

Transfer less data.Provide option to override.

Stream lower-quality video.Download low-resolution pictures.Retrieve only email headers.Postpone tasks that transfer data.

Fixed or Variable OverDataLimit or Roaming is true

Don’t transfer data.Provide option to override.

Stop downloading video.Stop downloading pictures.Do not retrieve email.Postpone tasks that transfer data.

Demo 6: Data Sense APIs

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Network Security

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Encrypting the Communication

• You can use SSL (https://...) to encrypt data communications with servers that

have an SSL server cert

• Root certificates for the major Certificate Authorities (Digicert, Entrust,

Verisign, etc…) are built into Windows Phone 8• Your app can simply access an https:// resource and the server certificate is

automatically verified and the encrypted connection set up• SSL Client certificates are not supported, so mutual authentication scenarios are not

possible

• You can install a self-signed cert into the Windows Phone Certificate Store• Expose the .cer file on a share or website protected by authentication• Alllows you to access private servers secured by a self-signed server certificate

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Authentication

• As well as encrypting data in transit, you also need to authenticate the client to

make sure they are allowed to access the requested resource

• For communications over the Internet, secure web services using Basic HTTP

authentication• Transfers the username and password from client to server in clear text, so

this must be used in conjunction with SSL encryption

• For Intranet web services, you can secure them using Windows or Digest

authentication•Windows Phone 8 supports NTLM and Kerberos authentication

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Adding Credentials to an HttpWebRequest

private void PhoneApplicationPage_Loaded(object sender, RoutedEventArgs e){ var request = HttpWebRequest.Create("http://myServer:15500/NorthwindDataService.svc/Suppliers") as HttpWebRequest; request.Credentials = new NetworkCredential("username", "password"); // override allows domain to be specified request.Accept = "application/json;odata=verbose"; // Must pass the HttpWebRequest object in the state attached to this call // Begin the request… request.BeginGetResponse(new AsyncCallback(GotResponse), request);} 

• Provide your own UI to request the credentials from the user• If you store the credentials, encrypt them using the ProtectedData class

Encrypting Sensitive Data Using ProtectedData

private void StoreCredentials() { // Convert the username and password to a byte[]. byte[] secretByte = Encoding.UTF8.GetBytes(TBusername.Text + "||" + TBpassword.Text);

// Encrypt the username by using the Protect() method. byte[] protectedSecretByte = ProtectedData.Protect(secretByte, null);

// Create a file in the application's isolated storage. IsolatedStorageFile file = IsolatedStorageFile.GetUserStoreForApplication(); IsolatedStorageFileStream writestream = new IsolatedStorageFileStream(FilePath, System.IO.FileMode.Create, System.IO.FileAccess.Write, file);

// Write data to the file. Stream writer = new StreamWriter(writestream).BaseStream; writer.Write(protectedSecretByte, 0, protectedSecretByte.Length); writer.Close(); writestream.Close(); } 

Decrypting Data Using ProtectedData

// Retrieve the protected data from isolated storage. IsolatedStorageFile file = IsolatedStorageFile.GetUserStoreForApplication(); IsolatedStorageFileStream readstream = new IsolatedStorageFileStream(FilePath, System.IO.FileMode.Open, FileAccess.Read, file);

// Read the data from the file. Stream reader = new StreamReader(readstream).BaseStream; byte[] encryptedDataArray = new byte[reader.Length];

reader.Read(encryptedDataArray, 0, encryptedDataArray.Length); reader.Close(); readstream.Close();

// Decrypt the data by using the Unprotect method. byte[] clearTextBytes = ProtectedData.Unprotect(encryptedDataArray, null);

// Convert the byte array to string. string data = Encoding.UTF8.GetString(clearTextBytes, 0, clearTextBytes.Length); 

Summary

•WebClient and HttpWebRequest for HTTP communications

•Windows Phone has a sockets API to support connection-oriented and

connectionless TCP/IP and UDP/IP networking

• Support for ASMX, WCF and REST Web Services

•DataServicesClient for OData service access out of the box in 7.1 SDK

• Consider JSON serialization for maximum data transfer efficiency

•Windows Phone 8 supports Basic, NTLM, digest and Kerberos authentication

• Encrypt sensitive data on the phone using the ProtectedData class

The information herein is for informational purposes only an represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be

interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation.

© 2012 Microsoft Corporation.

All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.

MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.