Topic Last Modified: 2011-03-25
The following figure is a conceptual overview of how DNS, Global, and Local server load balancing were configured to support the metropolitan site resiliency solution.
In this topology, Global Server Load Balancers (GSLB) were deployed at each site to provide failover capabilities at a site level, supporting internal client/server (https) traffic to the pool and external reverse proxy (https) traffic for users connected remotely. As part of this configuration, Local Server Load Balancers (LSLB) were also deployed at each site to manage https connections to Front End servers within the pool, physically located across each site. To support the DNS zones delegated internally and externally, the GSLB at each site monitored and routed https traffic destined for the following URLs:
To support the simple URLs referenced above, CNAME records were created, delegating the DNS resolution to the GSLB for further routing to the LSLB of choice. For example, as internal client requests resolved to webpool1.contoso.com, they were translated to webpool1.wip.contoso.com by the GSLB and traffic was routed to one of the local server load balancers virtual IP addresses (VIPs) as shown.
If a site failure occurred, the GSLB would redirect future requests to the LSLB VIP that remains.
For all other Lync Server client-to-server and server-to-server traffic, external or internal, the requests were handled by DNS load balancing, which is a new load balancing capability in Lync Server 2010.