Benefits of load balancing Skype for Business

Deploying Skype for Business with a load balancer enables organizations to create a feature-rich highly resilient solution that ensures that wherever staff are located, and however they connect, they can depend on a platform that allows seamless communications wherever and whenever needed using the communications medium of their choice.

About Skype for Business

Skype for Business is a business class instant messaging, voice over IP (VoIP) and video collaboration tool by Microsoft. Since 2015, it has served as a replacement for Microsoft Lync (formerly Microsoft Office Communications Server).

Unlike the consumer version of Skype, the infrastructure for is hosted on Skype for Business Server. This is comprised a number of individual servers including, Frontend/Backend, Mediation, Director and Edge servers. Due to the number of servers and services provisioned, there is inherent complexity in the deployment. This requires a considered approach to high availability and distribution of user traffic.

Why Loadbalancer.org for Skype for Business?

Loadbalancer’s intuitive Enterprise Application Delivery Controller (ADC) is designed to save time and money with a clever, not complex, WebUI. 

Easily configure, deploy, manage, and maintain our Enterprise load balancer, reducing complexity and the risk of human error. For a difference you can see in just minutes.

And with WAF and GSLB included straight out-of-the-box, there’s no hidden costs, so the prices you see on our website are fully transparent.

More on what’s possible with Loadbalancer.org.

How to load balance Skype for Business

Loadbalancer.org appliances are configured to present a series of Virtual Servers (VIPs). These VIPs become the connection points for internal and external clients. The load balancer is then able to distribute requests to the Skype for Business servers that make up the various pools.

Direct Routing (DR) mode a.k.a. Direct Server Return (DSR) mode is not supported for Skype for Business.

UDP traffic must be configured with Layer 4 NAT mode.

TCP traffic can use either Layer 7 Reverse Proxy or Layer 4 NAT.

Front end servers protocols

Protocol	Role	Ports	Load balancing methods
TCP/HTTP	Internal Web Services	Internal Web Services	Layer 7 Reverse Proxy – (Flexible, Source IP and cookie insertion capabilities)
TCP/DCOM/RPC	Various DCOM based operations	135	Layer 7 Reverse Proxy – (Flexible, Source IP and cookie insertion capabilities)
TCP/HTTPS	Internal Web Services: Used for HTTPS communication between the Focus (the Skype for Business Server component that manages conference state) and the individual servers.	443,444	Layer 7 Reverse Proxy – (Flexible, Source IP and cookie insertion capabilities)
TCP/TURN	Used for call admission control by the Skype for Business ServerBandwidth Policy Service	448	Layer 7 Reverse Proxy – (Flexible, Source IP and cookie insertion capabilities)
TCP/TLS/MTLS/SIP	Various SIP based communication	5061	Layer 7 Reverse Proxy – (Flexible, Source IP and cookie insertion capabilities)
TCP/SIP/TLS	Used by the Mediation Server for incoming requests from the Front EndServer to the Mediation Server	5070	Layer 7 Reverse Proxy – (Flexible, Source IP and cookie insertion capabilities)
TCP/SIP/MTLS	Used for incoming SIP requests for the Response Group application, Attendant (dial in conferencing), the Skype for Business Server Conferencing Announcement service (that is, for dial-in conferencing), the Call Park application	5071, 5072, 5073, 5075	Layer 7 Reverse Proxy – (Flexible, Source IP and cookie insertion capabilities)
TCP/SIP	Used for incoming SIP requests for the Audio Test service	5076	Layer 7 Reverse Proxy – (Flexible, Source IP and cookie insertion capabilities)
TCP	Used for call admission control by the Bandwidth Policy service for A/VEdge TURN traffic	5080	Layer 7 Reverse Proxy – (Flexible, Source IP and cookie insertion capabilities)
TCP/HTTPS	External Web Services – from Reverse Proxy	4443	Layer 7 Reverse Proxy – (Flexible, Source IP and cookie insertion capabilities)
TCP/HTTPS	External Web Services – from Reverse Proxy	8080	Layer 7 Reverse Proxy – (Flexible, Source IP and cookie insertion capabilities)

Director servers protocols

Protocol	Role	Ports	Load balancing methods
TCP/HTTPS	Internal Web Services	443	Layer 7 Reverse Proxy – (Flexible, Source IP and cookie insertion capabilities)
TCP/HTTPS	Inter-server communication between Front End and Director	444	Layer 7 Reverse Proxy – (Flexible, Source IP and cookie insertion capabilities)
TCP/TLS/MTLS/SIP	Internal SIP communications between servers and for client connections	5061	Layer 7 Reverse Proxy – (Flexible, Source IP and cookie insertion capabilities)
TCP/HTTP	External Web Services – from Reverse Proxy	4443	Layer 7 Reverse Proxy- (Flexible, Source IP and cookie insertion capabilities)
TCP/HTTP	External Web Services – from Reverse Proxy	8080	Layer 7 Reverse Proxy – (Flexible, Source IP and cookie insertion capabilities)

Edge servers (external interface)/access (SIP) service protocols

Protocol	Role	Ports	Load balancing methods
TCP/STUN	Audio/Visual service	443	Layer 4 NAT – (Fast Load balancing throughput Source IP persistence) or Layer 7 Reverse Proxy – (Flexible, Source IP persistence)
UDP/STUN	Audio/Visual service	3478	Layer 4 NAT – (Fast Load balancing throughput Source IP persistence) or Layer 7 Reverse Proxy – (Flexible, Source IP persistence)
TCP/MTLS/SIP	Access (SIP proxy) service	5061	Layer 4 NAT – (Fast Load balancing throughput Source IP persistence) or Layer 7 Reverse Proxy – (Flexible, Source IP persistence)
TCP/MTLS/SIP	Audio/Visual authentication service	5062	Layer 4 NAT – (Fast Load balancing throughput Source IP persistence) or Layer 7 Reverse Proxy – (Flexible, Source IP persistence)

Web conference service protocols

Protocol	Role	Ports	Load balancing methods
TCP/TLS/STUN/SIP	Web conferencing	443	Layer 7 Reverse Proxy – (Source IP persistence)

Audio/visual service protocols

Protocol	Role	Ports	Load balancing methods
TCP/TLS/STUN/SIP	Access (SIP proxy), Web Conferencing, Audio/Visual services	443	Layer 4 NAT – (Fast Load balancing throughput Source IP persistence) or Layer 7 Reverse Proxy – (Flexible, Source IP persistence)
UDP/STUN	Audio/Visual service	3478	Layer 4 NAT – (Fast Load balancing throughput Source IP persistence) or Layer 7 Reverse Proxy – (Flexible, Source IP persistence)

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