Call Queue Timers and Tips

If you need backup or alternate agents to answer a call, Call Queues offer a number of ways to do this with call distribution methods like round robin or serial routing. Every so often, I encounter an organization that wants to have a second Call Queue be a backup or escalation for a primary Call Queue.

This could be because the primary Call Queue already has multiple agents that are busy, so a second Call Queue is needed to add a second list of ordered agents. It can often be because the organization wants a different call routing method used for the backup vs the primary. For example, the primary might be round-robin, and the back might be attendant. That would be a case of “if you’ve tried everyone available in customer service in round-robin, now try everyone in inside sales at the same time”.

There are some considerations here with Call agent alert time (how long each agent rings for) and call timeout handling (how long the caller is in this queue before some timeout action takes place), as well as the Call overflow handling (what to do when there are too many callers waiting in this queue).

Let’s start with a simple example. If you have an Agent Alert time of 15 seconds and a Call Timeout value of 20 seconds, the caller will remain in the queue for 30 seconds:

This is because the “Call Timeout” value is only considered each time the Agent Alert Time expires. At the 15 second mark, the first Agent Alert time has expired, Teams checks the Call Timeout and it has not expired, so it rings another agent and keeps the caller in the Queue.

After 30 seconds when the second Agent Alert time expires, Teams checks the call Timeout and finds it has expired and takes the timeout action that you’ve defined.

Call Overflow handling takes place when a new caller would be added to the Queue. If the Overflow value is 10 and the 11th caller tries to join, Teams will instead use the call Overflow action that you’ve defined.

Let’s say your second queue overflow and timeout actions send the caller to voicemail. Your primary queue call timeout should send callers to the second queue. However, your primary queue overflow should send users directly to the voicemail and not to the second queue. This is because these callers are new and sending them directly to the second queue means that they are skipping the line and now have less time to wait for an agent than those callers waiting in the primary queue:

When Your IP Subnets Span Sites and Break Teams Location Things

Perhaps the most time consuming portion of the Teams voice projects that I’m involved in relates to location…  A Teams user’s location can be used for emergency calling, bandwidth consumption over constricted WAN or internet links, or things like location based routing and local media optimization.

One of the first questions I ask is: “Do you have subnets that span multiple buildings, especially for wifi”. For emergency calling, each building or facility may need to be broken up into “dispatchable locations” if you’re reading legislation or “places” in Teams lingo. Essentially, if you’re a large building like a school or factory, how do the first responders find you? That’s your “emergency response location” or your “place”. You’ll need a network characteristic to establish which place a Teams client is in. That could be subnet, the switch chassis ID, or the switch port on that switch you are connected to, or it could be the BSSID, which reflects which access point you’re connected to.

If you have IP subnets that span buildings, you will need to re-subnet in order to get the proper physical granularity that’s needed for location-based functions in Teams.  There are a couple of exceptions to this.

First, if the only spanned subnets you have are for server/storage infrastructure, you’re fine. Just ensure that phones can’t be plugged into this network (which you should be doing anyway!), especially a server room phone.

The second exception would be if you don’t need any Network Site based policies other than Emergency Calling Policy. This is the one that notifies someone at the facility that an emergency call has been placed. In the US, the FCC website says (this is Kari’s law):

“When a 911 call is placed on a MLTS system, the system must be configured to notify a central location on-site or off-site where someone is likely to see or hear the notification.”


Typically, you would need to notify someone at that site about the emergency call, and “that site” has IP subnets associated with it, and an Emergency Calling Policy associated with it. The Emergency Calling Policy handles the notifications, so if a subnet spans multiple sites, you can see how this makes it impossible to notify someone only at the site from which the call was placed.

There are two options or scenarios here. The first is one in which you can notify parties at both/all sites, and train them how to tell when a call is from their site, and to take appropriate action. The second would be when you have something like a central security desk that can be notified, and that security desk can then take appropriate action – commonly this is facilitating first responder access to the building, but it could also be first aid or security teams responding to the incident.

A university campus is an example of a site where I common encounter IP subnets that span sites/buildings/facilities. It’s also a great example of a site where this many not matter, and every university that I’ve encountered has security and/or police departments who can handle responses to these notifications.

An example of where things don’t work with spanned subnets would be a wifi subnet that spans the facilities for a municipality that doesn’t have a security desk (though they may have some “in charge” of security). A call to emergency services from a library would need to notify someone at the library, and not HR, IT or city hall reception. This isn’t so much because they couldn’t in turn notify someone else at the library to take action. My concern here would mainly be around availability and hours of work. If the library is open until 9pm and HR, IT, and city hall are all closed, you’re not notifying anyone.

In a case like this, I would recommend the city to re-subnet their wifi. In some cases, depending on their wifi controller(s), this could be a painful exercise, as some wifi controllers cannot have a single SSID (which is desirable) across the organization use a different subnet at each location. Instead, one SSID would need to be created per location, and then all of the wifi clients at that location would need to have their wireless connections updated to the new SSID. That’s no fun but is necessary in many cases to properly meet emergency calling legislation, or to use other location-based policies like Network Roaming (WAN/Internet bandwidth consumption limits for Teams, based on the site).