LS Routing Applications Test

The VoIP components located on Front End Servers of the Microsoft Skype for Business server are as follows:

  • Translation Service
  • Inbound Routing component
  • Outbound Routing component
  • Exchange UM Routing component
  • Intercluster Routing component
  • Mediation Server component in Skype for Business Server 2013

When a call request is received by the front end servers, the components mentioned above processes the call requests and routes it to the destination. Whenever the requests stagnate and are unable to be routed, the requests time out. Administrators may want to identify the exact technical glitch that caused a large number of call requests to time out frequently in the registrar pools of the front end servers. This is where the LS Routing Applications test helps! This test reports on how well the call requests are processed and how many requests timed out in the primary and backup registrar pools. Alongside, administrators may be alerted to the number of emergency calls received and the telephone numbers that were translated.

Target of the test : A Microsoft Skype for Business server

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for the target Microsoft Skype for Business server that is to be monitored.

Configurable parameters for the test
Parameters Description

Test Period

How often should the test be executed.


The host for which the test is to be configured.


The port at which the specified host listens. The default port is 5060.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Inter cluster routing requests

Indicates the number of call requests processed by the intercluster routing component.


The Intercluster routing component is responsible for routing calls to the callee’s primary Registrar pool. If that is unavailable, the component routes the call to the callee’s backup Registrar pool. If the callee’s primary and backup Registrar pools are unreachable over the IP network, the Intercluster routing component reroutes the call over the PSTN to the user’s telephone number.

Primary registrar timeouts

Indicates the number of call requests that timed out in the primary registrar pool.


The Skype for Business Server Registrar is a server role that enables client registration and authentication and provides routing services. It resides along with other components on a Standard Edition server, Front End Server, Director, or Survivable Branch Appliance. A Registrar pool consists of Registrar Services running on the Front End pool and residing at the same site. A Skype for Business client discovers the Front End pool through the following discovery mechanism:

  • DNS SRV record
  • Autodiscovery Web Service (new in Skype for Business Server 2013)
  • DHCP option 120

After the Skype for Business client connects to the Front End pool, it is directed by the load balancer to one of the Front End Servers in the pool. That Front End Server, in turn, redirects the client to a preferred Registrar in the pool.

Each user enabled for Enterprise Voice is assigned to a particular Registrar pool, which becomes that user’s primary Registrar pool.

To assure voice resiliency in the event of a central site failure, the primary Registrar pool must have a single designated backup Registrar pool located at another site. Assuming a resilient WAN link between the two sites, users whose primary Registrar pool is no longer available are automatically directed to the backup registrar pool.

Backup registrar timeouts

Indicates the number of call requests that timed out in the backup registrar pool.



Received emergency calls

Indicates the number of emergency calls received in the pool.



Emergency call failure responses

Indicates the number of emergency calls that failed to receive a response at the gateway.


Ideally, the value of this measure should be zero.

Phone numbers translated

Indicates the total number of telephone numbers translated by the Translation Service.


The Translation Service is the server component that is responsible for translating a dialed number into the E.164 format or another format, according to the normalization rules that are defined by the administrator. The Translation Service can translate to formats other than E.164 if your organization uses a private numbering system or uses a gateway or PBX that does not support E.164.