802.11ac Is Here, 5 Things You Need To Know

Gigabit Wi-Fi, 802.11ac, is officially here, but what does that really mean? Here’s my list of the five things you need to know before you invest in this new wireless technology.

1) 802.11ac is not going to give you a Gigabit of throughput

True, 802.11ac access points working with 802.11ac devices will give you faster data transmission feeds than 802.11n. The Wi-Fi Alliance claims that Wi-Fi Certified 802.11ac can deliver data rates up to more than double those of a typical 802.11n network. Practically speaking the Alliance claims that “this means a network can support simultaneously streaming multiple HD-quality videos to multiple devices.”

Fair enough, but in practice you’re not likely to see an 802.11ac reach its theoretical maximum of 1.3 Gigabit per second (Gbps). That’s because the conditions you need to reach that speed requires a laboratory not your office.

To reach the highest speeds you need three data-streams, each of which can run up to 433 Megabits per second (Mbps). A typical 802.11ac access point can support up to eight data streams. Client devices must only support one.

For example, the Samsung Galaxy S4 supports 802.11ac with the Broadcom BCM4335 Wi-Fi chipset. This chipset only supports a single stream so, even in the best of all possible worlds, you’ll only see 433Mbps.

The “unofficial” 802.11ac devices that have been shipping for the last few months, and the first generation of the standard 802.11ac devices aren’t likely to hit these speeds even on a testbed. The fastest speeds here in CNeET/ZDNet land we’ve seen to date came from the NetGear R6300 WiFi Router, which hit a high of 331Mbps.

That’s great, but it’s not gigabit great. It is, however, a lot faster than you’ll see then with any combination of 802.11n gear.

2) Working out the range

802.11ac only supports the 5GHz frequency. The good news about that is that there’s far more room in that frequency spread than there is in the over-used 2.4GHz . The bad news is that a 5GHz signal has less range.

At the same time, 802.11ac has another feature, beam-forming, that gets around the general 5Ghz range problem. For the Wi-Fi access point in your office today, the signal is omni-directional—it forms a communications sphere around the device. With 802.11ac the signal is broadcast directly from the access point (AP) to a specific device and back again.

While no one seems to have published much on what this means, I expect it means that if you’re in an environment with few 802.11ac devices, say eight, you’ll actually see excellent range. But, if you’re in at a convention center with hundreds of 802.11ac devices I suspect you’ll need to be much closer to an AP to get a signal. That said, life is always miserable for Wi-Fi users in hotels and large meetings rooms.

3) Backwards Compatibility

All 802.11ac devices will support older Wi-Fi technologies such as your 802.11n-equipped laptop or even your old 802.11g network bridge. 802.11ac can’t do magic though. For example, if you buy an 802.11ac AP you’ll still be limited to your older devices’ maximum speeds.

Soon, there will be a lot of new gear that supports 802.11ac as clients. If you buy an 802.11ac AP now you’re really buying for future use. It’s not going to do you much good today.

As always you should remember that any network is only as fast as its slowest link. For instance, if you’re buying 802.11ac to improve your Netflix viewing experience and your Internet connect is 10Mbps, it won’t do you a darn bit of good. 802.11n, or even 802.11g, is all you’ll need.

4) AP Channel Conflict Ahoy

Anyone who does any Wi-Fi network management knows that the 2.4GHz range is as crowded as a Best Buy store on Black Friday morning. In theory, you can use up to 14 channels. In practice, to avoid interference, you can only use three or four channels. If you have conflicting channels, you’ll see your network performance go down the toilet. The advantage of 802.11a and 802.11n’s 5Ghz range is that was so much room that you didn’t need to worry about interference. Get worried again.

One of the big ways that 802.11ac gains its speed is by using 80MHz wide channels. In 802.11ac wave two devices–the next generation of 802.11ac, which will start showing up in 2014–the channels will take up 160MHz of frequency. What that means exactly depends on your country, since there are a wide variety of rules on how the 5GHz range can be used. But, in the United States that means 802.11ac will have at most five available channel selections. When 802.11ac second-wave appears it will go down to one or two.

80211acChannels
The 5GHz frequency range is messy, and using it is only going to get a lot messier as 802.11ac continues to evolve. (Credit: Cisco)

In other words, network administrators should start working out now where they’ll be placing 802.11ac APs, because once more you’ll need to be wary of fouling up performance because of AP interference. And, let’s not talk about that business on the floor below you that’s always munging up your network.

5) 802.11ac requires additional infrastructure

I know, you thought 802.11ac would let you get rid of some of your Gigabit wiring. Nope. Not going to happen. First, as I already explained you’re not really going to get Gigabit speeds out of 802.11ac.

Second, and what many people don’t know, is that second-wave 802.11ac APs will require two, not one, Gigabit Ethernet ports. That just doubled your need for switch ports and cable runs. Oh boy!

Sure, you can get by with one port for now, but remember you’re not really going to have that many 802.11ac clients in 2013. Next year is when they’ll start showing up in large numbers and that’s when the second wave 802.11ac APs will be appearing.

So, you can forget about doing a drop and replace for your existing 802.11g/n network APs. You won’t be able to do it. Look on the bright side: Even with the next generation of 802.11ac you probably won’t need to back them up with 10Gbps up-links.

What all this means is that Gigabit Wi-Fi isn’t really here. Faster Wi-Fi is but it’s not really going to take off until 2014 and when it does come deploying it is going to be expensive. I foresee all of us using 802.11n Wi-Fi for years still to come. 802.11ac is not going to roll out quickly.

Share XP Files With Windows 10

Summary

With Windows XP, you can share files and documents with other users on your computer and with other users on a network. There is a new user interface (UI) named Simple File Sharing and a new Shared Documents feature. This article describes the new file sharing UI and discusses the following topics:

  • How to turn Simple File Sharing on and off
  • How to manage and configure levels of access to shares and files
  • Guidelines for file sharing in Windows XP
  • Advanced troubleshoot file sharing problems
INTRODUCTION

On a Windows XP-based computer, you can share files among both local and remote users. Local users log on to your computer directly through their own accounts or through a Guest account. Remote users connect to your computer over the network and access the files that are shared on your computer.

You can access the Simple File Sharing UI by viewing a folder’s properties. Through the Simple File Sharing UI, you can configure both share and NTFS file system permissions at the folder level. These permissions apply to the folder, all the files in that folder, subfolders, and all the files in the subfolders. Files and folders that are created in or copied to a folder inherit the permissions that are defined for their parent folder. This article describes how to configure access to your files, depending on permission levels. Some information that this article contains about these permission levels is not documented in the operating system files or in the Help file.

More information

With file sharing in Windows XP, you can configure five levels of permissions. You can configure Levels 1, 2, 4, and 5 by using the Simple File Sharing UI. To do this, right-click the folder, and then click Sharing and Security to open the Simple File Sharing UI. To configure Level 3, copy a file or a folder into the “Shared Documents” folder under “My Computer.” This configuration does not change when you turn on or turn off Simple File Sharing. Level 1 is the most private and secure setting, while Level 5 is the most public and the most changeable (nonsecure) setting.

Turning on and turning off Simple File Sharing

Note Windows XP Home Edition-based computers always have Simple File Sharing enabled.

By default, the Simple File Sharing UI is turned on in Windows XP Professional-based computers that are joined to a workgroup. Windows XP Professional-based computers that are joined to a domain use only the classic file sharing and security interface. When you use the Simple File Sharing UI (that is located in the folder’s properties), both share and file permissions are configured.

If you turn off Simple File Sharing, you have more control over the permissions to individual users. However, you must have advanced knowledge of NTFS and share permissions to help keep your folders and files more secure. If you turn off Simple File Sharing, the Shared Documents feature is not turned off.

To turn Simple File Sharing on or off in Windows XP Professional, follow these steps:

  1. Click Start, and then click My Computer on the desktop.
  2. On the Tools menu, click Folder Options.
  3. Click the View tab, and then select the Use Simple File Sharing (Recommended) check box to turn on Simple File Sharing. (Clear this check box to turn off this feature.)

Managing levels of access to shares and to files

You can use Simple File Sharing to configure five levels of access to shares and files:

  • Level 1: My Documents (Private)
  • Level 2: My Documents (Default)
  • Level 3: Files in shared documents available to local users
  • Level 4: Shared Files on the Network (Readable by Everyone)
  • Level 5: Shared Files on the Network (Readable and Writable by Everyone)

Notes

  • By default, files that are stored in “My Documents” are at Level 2.
  • Levels 1, 2, and 3 folders are available only to a user who is logging on locally. Users who log on locally include a user who logs on to a Windows XP Professional-based computer from a Remote Desktop (RDP) session.
  • Levels 4 and 5 folders are available to users who log on locally and remote users from the network.

The following table describes the permissions:

Access Level Everyone (NTFS/File) Owner System Administrators Everyone (Share)
Level 1 Not available Full Control Full Control Not available Not available
Level 2 Not available Full Control Full Control Full Control Not available
Level 3 Read Full Control Full Control Full Control Not available
Level 4 Read Full Control Full Control Full Control Read
Level 5 Change Full Control Full Control Full Control Full Control
 Level 1: My Documents (Private)

The owner of the file or folder has read and write permission to the file or folder. Nobody else may read or write to the folder or the files in it. All subfolders that are contained in a folder that is marked as private remain private unless you change the parent folder permissions.

If you are a Computer Administrator and create a user password for your account by using the User Accounts Control Panel tool, you are prompted to make your files and folder private.

Note The option to make a folder private (Level 1) is available only to a user account in its own My Documents folder.

To configure a folder and all the files in it to Level 1, follow these steps:

  1. Right-click the folder, and then click Sharing and Security.
  2. Select the Make this Folder Private check box, and then click OK.

Local NTFS Permissions:

  • Owner: Full Control
  • System: Full Control

Network Share Permissions:

  • Not Shared

Level 2 (Default): My Documents (Default)

The owner of the file or folder and local Computer Administrators have read and write permission to the file or folder. Nobody else may read or write to the folder or the files in it. This is the default setting for all the folders and files in each user’s My Documents folder.
To configure a folder and all the files in it to Level 2, follow these steps:

  1. Right-click the folder, and then click Sharing and Security.
  2. Make sure that both the Make this Folder Private and the Share this folder on the network check boxes are cleared, and then click OK.

Local NTFS Permissions:

  • Owner: Full Control
  • Administrators: Full Control
  • System: Full Control

Network Share Permissions:

  • Not Shared

Level 3: Files in shared documents available to local users

Files are shared with users who log on to the computer locally. Local Computer Administrators can read, write, and delete the files in the Shared Documents folder. Restricted Users can only read the files in the Shared Documents folder. In Windows XP Professional, Power Users may also read, write, or delete any files in the Shared Documents Folder. The Power Users group is available only in Windows XP Professional. Remote users cannot access folders or files at Level 3. To allow remote users to access files, you must share them out on the network (Level 4 or 5).

To configure a file or a folder and all the files in it to Level 3, start Microsoft Windows Explorer, and then copy or move the file or folder to the Shared Documents folder under My Computer.

Local NTFS Permissions:

  • Owner: Full Control
  • Administrators: Full Control
  • Power Users: Change
  • Restricted Users: Read
  • System: Full Control

Network Share Permissions:

  • Not Shared

Level 4: Shared on the Network (Read-Only)

Files are shared for everyone to read on the network. All local users, including the Guest account, can read the files. But they cannot modify the contents. Any user can read and change your files.

To configure a folder and all the files in it to Level 4, follow these steps:

  1. Right-click the folder, and then click Sharing and Security.
  2. Click to select the Share this folder on the network check box, click to clear the Allow network users to change my files check box, and then click OK.

Local NTFS Permissions:

  • Owner: Full Control
  • Administrators: Full Control
  • System: Full Control
  • Everyone: Read

Network Share Permissions:

  • Everyone: Read

Level 5: Shared on the network (Read and Write)

This level is the most available and least secure access level. Any user (local or remote) can read, write, change, or delete a file in a folder shared at this access level. We recommend that this level be used only for a closed network that has a firewall configured. All local users including the Guest account can also read and modify the files.

To configure a folder and all the files in it to Level 5, follow these steps:

  1. Right-click the folder, and then click Sharing and Security.
  2. Click to select the Share this folder on the network check box, click to select the Allow network users to change my files check box, and then click OK.

Local NTFS Permissions:

  • Owner: Full Control
  • Administrators: Full Control
  • System: Full Control
  • Everyone: Change

Network Share Permissions:

  • Everyone: Full Control

Note All NTFS permissions that refer to Everyone include the Guest account.

All the levels that this article describes are mutually exclusive. Private folders (Level 1) cannot be shared unless they are no longer private. Shared folders (Level 4 and 5) cannot be made private until they are unshared.

If you create a folder in the Shared Documents folder (Level 3), share it on the network, and then allow network users to change your files (Level 5), the permissions for Level 5 are effective for the folder, the files in that folder, and the subfolders. The other files and folders in the Shared Documents folder remain configured at Level 3.

Note The only exception is if you have a folder (SampleSubFolder) that is shared at Level 4 inside a folder (SampleFolder) that is shared at Level 5. Remote users have the correct access level to each shared folder. Locally logged-on users have writable (Level 5) permissions to the parent (SampleFolder) and child (SampleSubFolder) folders.

Note If you are not comfortable with the information that is presented in this section, ask someone for help or contact support. For information about how to contact support, visit the Microsoft Help and Support contact information Web site:

Guidelines

We recommend that you only share folders on the network that remote users on other computers must access. We recommend that you do not share the root of the system drive. When you do this, your computer is more vulnerable to malicious remote users. The Sharing tab of the drive’s Properties dialog box contains a warning when you try to share a root folder (for example, C:\). To continue, you must click the If you understand the risk but still want to share the root of the drive, click here link. Only computer administrators can share the root of the drive.

Files on a read-only device such as a CD-ROM shared at Level 4 or 5 are available only if the CD-ROM is in the CD drive. Any CD-ROM that is in the CD drive is available to all users on the network.

A file’s permission may differ from the parent folder if one of the following conditions is true:

  • You use the move command at a command prompt to move a file into the folder from a folder on the same drive that has different permissions.
  • You use a script to move the file into the folder from a folder on the same drive that has different permissions.
  • You run Cacls.exe at a command prompt or a script to change file permissions.
  • Files existed on the hard disk before you installed Windows XP.
  • You changed a file’s permissions while Simple File Sharing was turned off on Windows XP Professional.

Note NTFS permissions are not maintained on file move operations when you use Windows Explorer with Simple File Sharing turned on.

If you turn on and turn off Simple File Sharing, the permissions on files are not changed. The NTFS and share permissions do not change until you change the permissions in the interface. If you set the permissions with Simple File Sharing enabled, only Access Control Entries (ACEs) on files that are used for Simple File Sharing are affected. The following ACEs in the Discretionary Access Control List (DACL) of the files or folders are affected by the Simple File Sharing interface:

  • Owner
  • Administrators
  • Everyone
  • System

Advanced troubleshooting for configuring file sharing in Windows XP

Note This section is intended for advanced computer users. If you are not comfortable with advanced troubleshooting, ask someone for help or contact support. For information about how to contact support, see the Microsoft Help and Support contact information Web site:

Expected upgrade behavior

A Windows 2000 Professional-based or a Windows NT 4.0-based computer that is joined to a domain or a workgroup that is upgraded to Windows XP Professional maintains its domain or workgroup membership respectively and has the classic file sharing and security UI turned on. NTFS and share permissions are not changed with the upgrade.

By default, if you upgrade a computer that is running Microsoft Windows 98, Windows 98 Second Edition, or Windows Millennium Edition that has “per share” sharing permissions to Windows XP, Simple File Sharing is always turned on. Shares that have passwords assigned to them are removed, and shares that have blank passwords remain shared after the upgrade.

If you upgrade a computer that is running Windows 98, Windows 98 Second Edition, or Windows Millennium Edition to Windows XP Professional and that computer is logged on to a domain, if that computer has share level access turned on and joins the domain while the Setup program is running, the computer starts with Simple File Sharing turned off.
By default, a Windows 98, Windows 98 Second Edition, or Windows Millennium Edition-based computer that is upgraded to Windows XP Home has Simple File Sharing turned on.

Known issues

For remote users to access files from the network (Levels 4 and 5), the Internet Connection Firewall (ICF) must be disabled on the network interface that the remote users connect through.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

298804 Internet firewalls can prevent browsing and file sharing

When Simple File Sharing is turned on, remote administration and remote registry editing does not work as expected from a remote computer, and connections to administrative shares (such as C$) do not work because all remote users authenticate as Guest. Guest accounts do not have administrative rights. When Simple File Sharing is turned on, if you configure specific user ACEs, remote users are not affected when Simple File Sharing is turned on because all remote users authenticate as Guest when Simple File Sharing is turned on.

Remote users may receive an “Access Denied” message on a share that they had connected to successfully before. This behavior occurs after the hard disk is converted to NTFS. This behavior occurs on Windows XP-based computers that have Simple File Sharing turned on that were upgraded from Windows 98, Windows 98 Second Edition, or Windows Millennium Edition. This behavior occurs because the default permissions of a hard disk that is converted to NTFS do not contain the Everyone group. The Everyone group is required for remote users who are using the Guest account to access the files To reset the permissions, stop sharing, and reshare the affected folders.

Behavior that is affected when Simple File Sharing is turned on

  • The Simple File Sharing UI in the properties of a folder configures both share and file permissions.
  • Remote users always authenticate as the Guest account.For more information, click the following article number to view the article in the Microsoft Knowledge Base:
    302927 Computer Management displays user account names when logged on as Guest
  • Windows Explorer does not keep permissions on files that are moved in the same NTFS drive. The permissions are always inherited from the parent folder.
  • On Windows XP Professional-based computers that have Simple File Sharing turned on and Windows XP Home Edition-based computers, the Shared Folders (Fsmgmt.msc) and Computer Management (Compmgmt.msc) tools reflect a simpler sharing and security UI.
  • In the Computer Management and Shared Folders consoles, the New File Share command is unavailable when you right-click the Shares icon. Also, if you right-click any listed share, the Properties and Stop Share commands are unavailable.

Behavior that is not caused by turning on Simple File Sharing

  • In Windows XP Home Edition, the Computer Management snap-in does not display the Local Users and Groups node. The Local Users and Groups snap-in cannot be added to a custom snap-in. This behavior is a limitation of Windows XP Home Edition. It is not caused by Simple File Sharing.
  • If you turn off the Guest account in the User Accounts Control Panel tool, only the guest’s ability to log on locally is affected. The account is not disabled.
  • Remote users cannot authenticate by using an account that has a blank password. This authentication is configured separately.
  • Windows XP Home Edition cannot join a domain. It can only be configured as a member of a workgroup.For more information, click the following article number to view the article in the Microsoft Knowledge Base:
    303606 Can log on without password by using Guest account after upgrade from Windows 2000
References

For information about how to configure file sharing in Windows Vista, visit the following Microsoft Web site:

Properties

Article ID: 304040 – Last Review: 06/19/2014 13:14:00 – Revision: 19.0

    • Microsoft Windows XP Home Edition

  • Microsoft Windows XP Professional