What’s New in Communications Server‘14 – DNS Load Balancing

DNS Load Balancing is a new feature in CS’14. it simplify HLB (Hardware Load Balancing) configuration, reduce dependence on HLB. DNS LB support
  • Internal Pool
  • Director Pool
  • Edge
  • All Server-Server and Client-Server SIP traffic
  • All Server-Server HTTP traffic and Media traffic
  • Draining of Applications
here is some of the DNS Load Balancing Sample Configuration.

OCS 2007 R2 HLB – DNS Configuration

Pool – Virtual IP ocspool.domain.com
FE FE1.domain.com
FE FE2.domain.com
FE FE3.domain.com

CS’14 DNS Load Balancing – DNS Configuration

Web Virtual IP ocsweb1.domain.com
Pool ocspool1.domain.com
Pool ocspool1.domain.com
Pool ocspool1.domain.com
FE FE1.domain.com
FE FE2.domain.com
FE FE3.domain.com

DNS A Record for FQDN resolves to Multiple IPs

what happen if there is a Failover. If connection to an IP fails, it will failover to the next IP in the list. Load balance across multiple servers through SIP traffic sent to multiple IPs.

If the server is going for maintenance. the Server IP1 is being drained (returns 503 with special header), send all traffic to the next IP (IP2)


About David Lim

David has over 15 years of experience in IT industry in designing and implementing Microsoft Solutions ranging from small to enterprise customer. He also has experience in designing and developing Microsoft Unified Communications, Collaboration and Office 365 solutions with focus on Exchange, Lync & SharePoint as well as strategic migration planning in complex business environments. He is specializing in architecture and design of Lync Voice deployments. He has been actively involved in various speaking engagements, the recent being the sessions on Lync On-Premise and Office Interoperability in September 2011 and Office 365 Introduction in November 2011. In recognition of his high-quality real-world technical excellence with the community and with Microsoft, David received the prestigious Microsoft Most Valuable Professional (MVP) Award in April 2011.
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