One of the biggest productivity killers in the warehouse occurs when wireless barcode scanners lose their connections to the mission-critical applications they rely on to do their jobs.  The result is that the worker cannot do their job until the dropped session problem is resolved. Other serious ramifications of dropped sessions are lost data, poor employee morale, and the need for additional mobile device inventory and support staff. This blog post will discuss the causes costs of dropped sessions.

 What is a dropped session?

A “dropped user session” is the result of a remote RF/Wireless terminal emulation device losing its connection to the host computer and application that it is feeding real-time bar-coded scanning information to and not being able to continue the current process when the connection is re-established.

Because of the frequency with which a connection disruption can occur, dropped user sessions are the number one problem associated with RF/Wireless 5250, 3270 and VT emulation environments. Therefore, it is very important to understand the true impact of this situation on the various entities within an enterprise.

Users of RF/Wireless 5250, 3270 and VT emulation solutions are typically scanning barcoded information on materials and goods as part of the process of tracking real-time inventory movement for distribution and retail warehousing enterprises. The information from these scanning sessions is transmitted to host applications that then process the information to provide accurate and timely accounting-related reporting and records retention.

Any disruption in the process of completing an accurate bar-code scanning session will result in a delay or disruption in the process of moving inventory from one location to another and can also result in generating inaccurate accounting information.

A dropped scanning session is not only frustrating and time-consuming for the user who is performing the scanning function, but also for the various IT-related personnel that must get involved to assist with remedial action to resolve the problem. Until recently, this problematic situation has had to be tolerated by both the users and IT-related personnel due to the lack of availability of an effective solution.

 What happens when a scanning session is dropped?

Scanning sessions can be dropped by the server-side host computer (IBM AS/400-iSeries, IBM Mainframe-zSeries, RS6000-pSeries, HP9000/HP-UX, Windows Server, etc.) when the connection to the client-side RF/Wireless 5250, 3270 or VT terminal device being used has been disrupted for any period of time. This can be caused by a variety of everyday client-side events including battery replacement, the user going out of access point range with a device, or a device reset or reboot.

The host server-side processes (jobs) linked to the client device scanning session become abandoned without possibility of re-linking to the client. New server-side processes will need to be established in order to accommodate the user wishing to complete the current scanning job/data collection work at hand.

IT personnel assigned to controlling active processes on the host computer must get involved to identify and delete the abandoned sessions from the system. It is often quite time consuming to identify precisely which process (or processes) are the exact ones tied to the dropped user scanning session. Without host-centric features like “Device Naming”, all scanning sessions on the host look the same and there are no indicators that identify processes abandoned this way.

The abandoned process continues to live/run, except it is no longer receiving data from the client device and will not again. Because starting a new client device scanning session will be required, the process that has been abandoned on the host will not be the one the new client-side session will establish contact with. Rather, the new client device session, once started, will spawn a request for a new corresponding server-side process to send its scanning data to.

Further complication for the IT staff is generated from the need to “clean up” behind an abandoned session on the host and preserve the integrity of the data acquisition application and related database records. For example, if a scanning job was partially complete at the time of the disruption, the user may elect to start a new session to redo the job from the beginning to make sure all items are scanned completely. The partially completed job entries must be located and backed out of the database to avoid duplication and resulting errors.

Another alternative is an equally tedious process that requires the user to confirm with someone on the IT side as to exactly which scanned items in the job were received correctly prior to the disruption. This needs to happen if they wish to determine where to resume the job from in a new session versus starting the job over from the beginning.

In either case, IT staff members must also clear certain “in use” application flags associated with the abandoned process. An application may be licensed according to the maximum number of simultaneous users and an abandoned process left “in use” will register as an active user to the system for licensed access control purposes until it is stopped.

In addition to users having to coordinate in real-time with IT staff members to deal with the dropped session and know where to pick up the process from, they are also impacted negatively by having to start a new client session on their end. To start a new session on the client-side, a user must go through the time-consuming process of signing on to the host computer gain. They must also call up and re-start the appropriate scanning application, and navigate to the appropriate point in the application where they left off. This is possible only if they were able to determine the exact point with certainty at all.

The bottom line is that all of the time and resources expended to get a user back on their way with the scanning job at hand when a dropped session occurs is 100% unproductive and takes all entities involved away from other important tasks in a reactionary and unplanned manner.

What are the costs associated with dropped scanning sessions?

In tangible terms, the following formula can provide a measurement of lost productivity costs associated with each incident, assuming the associated labor rates for the user and IT staff members involved is made available:

Time to resolve X (IT staff combined labor rate + Scanning user labor rate)

To appreciate the full impact of this situation, it is important to also consider the frequency with which a dropped scanning session is experienced on a daily basis. It is not uncommon for dropped sessions to occur several times in a day for various users if there is no mechanism in place to prevent them from happening.

Therefore, let us consider the following example using some conservative arbitrary numbers to illustrate the potential hard costs that can be realized from these productivity losses:

Assumptions for the example:
a) Average IT staff combined labor rate is $75.00 per hour
b) Average Scanning user labor rate is $25.00 per hour
c) Dropped scanning session problem-resolution time average is 15 minutes
d) Dropped scanning sessions occur 5 times per day per 25-30 wireless user facility as an average
15 mins. (0.25 hrs) X ($75.00 + $25.00) = $25.00 per X 5 = $125.00 Daily
Weekly = $625.00, Monthly = $2,500.00 and Annually = $30,000.00 per facility per year

 It is important to note that the example we are using here to illustrate hard costs is very conservative. Large enterprises experience a greater frequency of dropped session incidents based on larger numbers of simultaneously active scanning client users.

In addition to the pure costs associated with productivity losses, other potentially costly aspects associated to this situation and the resulting delays in inventory movement include missed shipping deadlines to customers, lack of available material for steps in a manufacturing process, warehouse location crowding as new material arrives for the same space, as well as a multitude of other factors impacting physical inventory logistics.


In order to prevent the potentially huge productivity time losses, as well as the tangible and intangible costs associated with dropped RF/Wireless 5250, 3270 and VT terminal sessions, any viable solution must feature server-based emulation architecture.

Otherwise, the best any other approach can hope to offer is a limiting of the impact of the dropped session situation and streamlining of remedial processes. Furthermore, the most reliable server/environment to run the emulation software on is usually the computing platform where the applications are hosted.

The conditions that cause wireless barcode scanning devices to lose connectivity with their hosts will always exist, but the impact on the end users can be addressed.  Click Here to find out how StayLinked can virtually eliminate dropped sessions for your business.

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