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One of the first things administrators learn about VDI is that the network is a tier 0 infrastructure. If the network isn't available or performing well, then virtualization is not a happy place.
With fast-enough networks, a virtual desktop can feel like a PC right in front of you. Slower networks make it obvious that the desktop is being hosted remotely. The ability to deliver a great network for VDI has extended out to more locations with faster wide-area networks (WANs), Wi-Fi and 4G mobile.
There is a transformation point in terms of bandwidth where a VDI session feels like a local PC. The actual VDI bandwidth that is needed is different for each remote display protocol.
I use VMware View with PCoIP all day when I'm at my office. With a link speed of 10 Mbps or better, the VDI session seems like a local PC. The session doesn't fill that 10 Mbps link all the time, but it does need that headroom for me to forget I don't have a PC on my desk.
In my organization, most of the people who use VDI are staffers sitting in our offices that are accessing desktops in our data centers. For the past five to 10 years, we have had 100 Mb Ethernet to the desktop with Gigabit Ethernet back to the data center. This LAN has provided great support for VDI.
If the data center is in the same building or campus as the virtual desktop user, then the network hasn't been a problem. Network throughput can be a challenge, however, when the data center is at the other end of the state, or even in another country. Then the WAN links joining our locations are the limiting factor.
The cost of high-bandwidth WAN links has been dropping for years, making multi-megabit WAN attractive. The use of Multiprotocol Label Switching (MPLS) networks and ongoing advances in Ethernet and Fiber Channel are bringing faster connections to more places. Improving WAN speeds allows VDI to be centralized, simplifying virtual desktop management.
Public and guest Wi-Fi
Cafés, hotels and client sites often provide Wi-Fi Internet access. This enables mobile users to access the corporate network and virtualized desktops from wherever they work. We can thank the rise of consumer smartphones and tablets for the wide availability of Wi-Fi access in public places. Nearly ubiquitous, free Wi-Fi allows employees to use various devices and avoid relatively expensive mobile data networks.
Corporate networks often have restrictive firewall settings. These could prevent access to our VDI environment. Many corporate networks are set up to allow access only by company-owned devices, locking us out of our client's corporate network.
Many organizations now implement guest Wi-Fi that only allows Internet access, with no corporate network access and no device restrictions. These networks are often an enabler for employee-owned client devices. Guest Wi-Fi is a great way to use VDI from client sites, and it removes the need to carry one client's data to another client's site.
4G mobile and flying wireless
For all the Wi-Fi availability, there are still times when staffers must be self-sufficient. This is where 4G mobile networks come in. 4G networks provide sufficient VDI bandwidth for a great session.
In comparison, 3G allowed for usable remote desktop sessions, but not great ones. 4G pushes over that 10 Mbps threshold to make PCoIP sessions feel local.
Mobile hotspot devices, such as the Novatel Mi-Fi, have made 4G connections as easy to use as a Wi-Fi hotspot. As more carriers deploy 4G to more cities, mobile users' VDI experience is improving and becoming available in more places.
One of the classic reasons for not using VDI while flying is that there is no Internet connection on a plane. This has changed a lot over the past few years. Some airlines now provide Wi-Fi-based Internet access on longer flights. While in-flight Wi-Fi won't be available at 4G speeds (or prices), it makes it possible to get work done using VDI while up in the air.
Challenges for VDI networks
While Wi-Fi and 4G are available in a lot of places, they are not available everywhere. Outside metropolitan centers, you may find yourself searching for Wi-Fi and falling back to 3G mobile. Hunting for Wi-Fi can take up a lot of time if you are travelling to remote locations.
You only get what you pay for. Even in some big cities, Wi-Fi can be poor, with low bandwidth and lots of congestion. This is particularly true of hotels beyond tech centers. A mobile data device such as Mi-Fi is a great fall back because even if it only provides 3G quality, you can still get work done.
Sometimes you don't even get good value when you pay. Travelers are well aware of the outrageous costs of international data roaming. Often, it is better to buy a local device and data service than to take the roaming costs. It only takes one $2,000 bill during a week overseas to bring that message home.
Even with a fast network link, there are things you may not want to do with a virtual desktop. With an excellent network, you can use Voice over Internet Protocol and video conferencing. With a good network, you can still watch training videos. If all you have is slow 3G mobile, you'd best wait for another network before using video of any kind over VDI.
Another challenge is the mobile devices our staff members use to access virtual desktops. In the office, a good zero client makes management simple and provides a great experience. Mobile devices will provide a less PC-like experience. Particularly with touch-based devices such as tablets, a Windows VDI session will have a different user interface for local applications.
VDI makes the network into a tier 0 infrastructure. Thankfully, both private and public network access have become fast and widely available. The connectivity objections to VDI are growing fewer every month.