You may know the saying: “Give a man a fish and you feed him for today. Teach a man to fish and you feed him for a lifetime.” Well, that is my intention with this series: To help you isolate the SFB issues based on the services delivering the respective features in UC world. In this way you can narrow down the issue to a specific component that need to be worked up on. In the below table, I’ll be explaining about the functionalities of different SFB services running on FE and Edge Servers.

 

Skype for Business FE Server Services:

1 Skype for Business Server Application Sharing SFB integrates many conferencing features, including Desktop Sharing and Application Sharing, into the client software. Selecting between these two feature elements determines whether participants see the entire desktop or only a single program during a conference. Port and protocol requirements are the same for both types.

Application Sharing uses RDP over SRTP/TCP and operates over media ports in the 49152-65335 range. The Front End servers listen for incoming requests on port 5065/TCP

2 Skype for Business Server Audio Test Service The Audio Test service enables Skype for Business Server 2015 users to test their voice connections before they make a voice call.
3 Skype for Business Server Audio Video Conferencing A/V conferencing enables real-time audio and video communications between your users.

Audio Conferencing Features

  1. Audience mute
  2. Conferencing Entry/Exit Announcements
  3. Adding a user by dialing out

Video Conferencing Features

  1. Gallery View
  2. Panoramic Video
  3. Presenter only video mode
  4. HD video
  5. Video Spotlight

  

4 Skype for Business Server Call Park Call Park enables an Enterprise Voice user to put a call on hold from one telephone and then retrieve the call later by dialing an internal number (known as a Call Park orbit) from any telephone.
5 Skype for Business Server Centralized Logging Service Agent ClsAgent runs on every machine with Skype for Business Server deployed. It listens (on ports TCP 50001-50003) for commands from ClsController over WCF and sends responses back to the controller. It manages log sessions (start/stop/update), and searches logs. It also performs housekeeping operations like log archiving and purges.
6 Skype for Business Server Conferencing Announcement Conferencing Announcement is a unified communications application that plays tones and prompts to PSTN participants on certain actions, such as when participants join or leave a conference, participants are muted or unmuted, someone enters the conference lobby, or the conference is locked or unlocked. Conferencing Announcement also supports dual-tone multifrequency (DTMF) commands from the phone keypad. Conferencing Announcement is automatically installed and activated by default when you deploy a Conferencing workload and select the dial-in conferencing option.
7 Skype for Business Server Conferencing Attendant Conferencing Attendant is a unified communications application that accepts public switched telephone network (PSTN) calls, plays prompts, and joins the calls to an A/V conference. Conferencing Attendant is installed and activated by default when you deploy a Conferencing workload and select the dial-in conferencing option
8 Skype for Business Server File Transfer Agent It is the responsibility of the FTA service running on the CMS master to copy the data packages from the master to the replicas. The FTA service has change notifications. Read reference for details
9 Skype for Business Server Front End
  1. User authentication and registration
  2.  Presence information and contact card exchange.
  3. Address book services and distribution list expansion
  4. IM functionality, including multiparty IM conferences
  5. Web conferencing, PSTN Dial-in conferencing and A/V conferencing (if deployed)
  6. Application hosting, for both applications included with Skype Server (for example, Conferencing Attendant and Response Group application), and third-party applications
  7. Monitoring to collect usage information in the form of call detail records (CDRs) and call error records (CERs). This information provides metrics about the quality of the media (audio and video) traversing your network for both Enterprise Voice calls and A/V conferences.
  8. Web components to supported web-based tasks such as web scheduler and join launcher.
  9. Optionally, Archiving, to archive IM communications and meeting content for compliance reasons.
10 Skype for Business Server Health Agent Helps in health monitoring, administrators can identify potential problems before they turn into actual problems.
11 Skype for Business Server IM Conferencing Enables group IM by relaying IM traffic among all participants. When a third participant is added to a peer-to-peer IM conversation, the initiating client invites the IM Conferencing Server to the conversation. From that point, all messages among the participants are routed through the IM Conferencing Server. The IM Conferencing Server is an integral part of the Front End Server and cannot be installed on a separate computer.
12 Skype for Business Server Master Replicator Agent

In every SFB Server deployment there is only a single master CMS and all servers running SFB have a local replica of CMS. All updates to information in CMS takes place at the master.

The location of the master is found by looking up a Service Connection Point (SCP) for the master CMS. Read reference for details

 

13 Skype for Business Server Mediation
  1. Encrypting and decrypting SRTP on the Skype for Business Server side.
  2. Translating SIP over TCP (for gateways that do not support TLS) to SIP over mutual TLS.
  3. Translating media streams between Skype for Business Server and the gateway peer of the Mediation Server.
  4. Connecting clients that are outside the network to internal ICE components, which enable media traversal of NAT and firewalls.
  5. Acting as an intermediary for call flows that a gateway does not support, such as calls from remote workers on an Enterprise Voice client.
  6. In deployments that include SIP trunking, working with the SIP trunking service provider to provide PSTN support, which eliminates the need for a PSTN gateway.
14 Skype for Business Server Replica Replicator Agent On a replica the REPLICA service has change notification on the “from-master” directory, it gets alerted when the FTA service has copied the data package to the replica. Read reference for details.
15 Skype for Business Server Response Group Manage certain types of calls, such as for customer service, an internal help desk, or general telephone support. The Response Group Service routes and queues incoming calls to designated persons, who are known as agents.
16 Skype for Business Server Web Conferencing Below are the features offered by this service

  1. Whiteboard and Annotations
  2. Polling
  3. Application Sharing and Desktop Sharing
  4. PowerPoint Sharing
17 Skype for Business Server XMPP Translating Gateway Service handles Outbound extensible messaging and presence protocol (XMPP)traffic from XMPP Gateway service running on Front End Server or Front End pool to Edge server or Edge Pool.

 

 

Skype for Business Edge Server Services:

1 Skype for Business Server Access Edge The Access Edge service provides a single, trusted connection point for both outbound and inbound Session Initiation Protocol (SIP) traffic.
2 Skype for Business Server Audio/Video Authentication Generates tokens for access to media relay.

MRAS explained.

3 Skype for Business Server Audio Video Edge The A/V Edge service makes audio, video, application sharing, and file transfer available to external users. Your users can add audio and video to meetings that include external participants, and they can communicate using audio and/or video directly with an external user in point-to-point sessions. The A/V Edge service also provides support for desktop sharing and file transfer.
4 Skype for Business Server Centralized Logging Service Agent ClsAgent runs on every machine with Skype for Business Server deployed. It listens (on ports TCP 50001-50003) for commands from ClsController over WCF and sends responses back to the controller. It manages log sessions (start/stop/update), and searches logs. It also performs housekeeping operations like log archiving and purges.
5 Skype for Business Server Replica Replicator Agent Responsible for pulling the latest update from the CMS master replica.
6 Skype for Business Server Web Conferencing Edge The Web Conferencing Edge service enables external users to join meetings that are hosted on your internal Server deployment.

 

 

Happy Learning…!!
Anoop Karikuzhiyil Babu
Former Microsoft Premier Unified Communication Engineer

By Anoop Karikuzhiyil Babu

Started his career with Exchange 2003 as a Microsoft Support Engineer, later moved to Microsoft Enterprise Unified Communication Team as Premier Engineer. Post handling numerous Premier environments and deployments, currently settled as a Solution Architect for Messaging and Collaboration in United Arab Emirates largest Tier3 Datacenter.