This section discusses the hardware load-balancer configuration for an Edge Server. There are two perspectives to look at for load balancing Edge Servers because the external-facing adapter and the internal-facing adapter have their own requirements. An Edge Server must be load balanced on both sides to function properly, but each side has slightly different requirements as shown in Figure 31.8.
Caution
Many load balancers have the option to balance “All Ports” for a given pool. Avoid this configuration, no matter how tempting and easy it seems. Instead, load balance only the ports found in the tables that follow. This allows the load balancer to properly monitor health of a particular service and use different persistence methods for each type of traffic.
Table 31.1 outlines which ports must be load balanced to each virtual IP address.
After the external interface load balancing has been configured, the internal adapter configuration must be completed. Unlike the external adapter that uses three virtual IP addresses, only a single virtual IP address is required for the internal adapter because each Edge Server has only a single IP address for its internal adapter.
Table 31.2 outlines which ports must be load balanced to each virtual IP address.
Caution
There is no entry here for load balancing the internal Web Conferencing Edge interface. That is not an omission or error; port 8057 on the internal interface should not be load balanced by the hardware load balancer. The Front End pools automatically distribute requests to multiple Web Conferencing Edge Servers if configured. Don’t forget to include TCP 8057 in the firewall rules, though, because even though it’s not load balanced, the Front End Servers need to be able to reach that port on Edge Servers.