A method for determining metrics of a content delivery and global traffic
management network provides service metric probes that determine the
service availability and metric measurements of types of services
provided by a content delivery machine. Latency probes are also provided
for determining the latency of various servers within a network. Service
metric probes consult a configuration file containing each DNS name in
its area and the set of services. Each server in the network has a metric
test associated with each service supported by the server which the
service metric probes periodically performs metric tests on and records
the metric test results which are periodically sent to all of the DNS
servers in the network. DNS servers use the test result updates to
determine the best server to return for a given DNS name. The latency
probe calculates the latency from its location to a client's location
using the round trip time for sending a packet to the client to obtain
the latency value for that client. The latency probe updates the DNS
servers with the clients' latency data. The DNS server uses the latency
test data updates to determine the closest server to a client.