When you weigh just the benefits of mobility, flexibility, and productivity, going wireless is a no-brainer. But factor in
roaming issues, spotty coverage on the corporate campus, and security vulnerabilities, and the decision can get complicated.
I looked at roaming solutions from ipUnplugged and NetMotion designed to solve these problems. Although the products take
slightly different tacks, they share the same goal: to provide secure, continuous connectivity to corporate applications over
inherently insecure and disparate wireless networks.
Both solutions appear equally matched when it comes to meeting subnet roaming expectations, enabling wireless sessions to
move across router boundaries without breaking the connection. Both have components that can be deployed on pretty much any
Intel-based hardware; both require a software client.
However, they also share a couple of major flaws. They support only a Windows-based mobile infrastructure and are limited
to networks that can transport IP.
Overall, NetMotion Mobility 5.01, a software-only solution, has a larger array of authentication infrastructure support to
manage users and groups. However, it’s also much more expensive than a similar deployment with ipUnplugged’s combined Roaming
Gateway, Server, and Client offering.
ipUnplugged
ipUnplugged leverages standards-based MobileIP and IPSec technology to create a solid, seamless roaming solution using what
is truly a mobile wireless VPN. Most interesting is that moving over different media types appears truly seamless. Although
ipUnplugged does not offer application persistence to the degree that NetMotion does, it is still a serious and reliable WLAN
mobility solution.
A typical deployment of ipUnplugged consists of a Roaming Gateway appliance, the Roaming Server —both of which are managed
via a Web-based interface —and the Roaming Client.
During my tests, I didn’t have a problem with roaming as much as I did with application persistence. Unlike NetMotion, ipUnplugged
doesn’t proxy for a client, so when a client application is cut off from its server, the client’s virtual adapter is still
up, but the session is no longer there. Depending on the robustness of the application, it may several minutes before it terminates.
Getting up and running with the Roaming Server was a fairly quick process. The server is the central location for network
configuration, security, and client management via a Web-based interface. Annoyingly, ipUnplugged requires at least an SMTP
infrastructure to function properly.
During installation, the Roaming Server installs its own RADIUS (Remote Authentication Dial-In User Service) server where
users and groups are managed. Although I could have also tied my RADIUS server to that of the Roaming Server’s to support
guest users, the ipUnplugged installation provides all subsequent authentications. Unfortunately, ipUnplugged supports only
RADIUS and SecureID but no other authentication methods.
The Roaming Gateway forwards traffic from app servers to the Roaming Client over whatever transport media may be present,
including GPRS, and CDPD (Cellular Digital Packet Data). The gateway, which typically sits between the enterprise network
on either the Internet or on a DMZ (demilitarized zone), has a built-in stateful firewall. The server automatically generates
the firewall rules during the process of creating the gateway.
I was up and running fairly quickly on the Roaming Gateway. The gateway provides a portal or a walled garden for users not
using the client software. The walled garden restricts WLAN guests to specific Web sites and can limit other protocols via
the firewall.
After the Roaming Gateway is installed, the Roaming Server sends an e-mail to each user with information on how to log on
and download the Roaming Client. This client software installation method is not ideal for an enterprise deployment. The vendor
did provide me with a command-line workaround.
The Roaming Client is unobtrusive and virtually transparent to the end-user. It manages both the security and type of media
connection to the corporate infrastructure. When on the corporate LAN, the client connects via unencrypted connection. When
on insecure media, such as a public hot spot, the client encrypts the connection and maintains a solid roaming connection
back to the corporate landscape.
There is no way to create reports of any kind regarding clients except via RADIUS accounting, nor is there a way to gather
client statistics via the Web-based interface. The RADIUS server can provide client information on session tine and byte/packets
information. However, the Roaming Server does provide detailed logs of server statistics.