Dell 3-DNS - Page 157

Glossary
3-DNS
®
Administrator Guide Glossary-11
topology record
A topology record specifies a score for a local DNS server location endpoint
and a virtual server location endpoint.
topology score
The topology score is the weight assigned to a topology record when the
3-DNS Controller is filtering the topology records to find the best virtual
server match for a DNS query.
topology statement
A topology statement is a collection of topology records.
traceroute
Traceroute is the utility that the hops factory uses to calculate the total
number of network hops between a local DNS server and a specific data
center.
TTL (Time to Live)
The TTL is the number of seconds for which a specific DNS record or
metric is considered to be valid. When a TTL expires, the server usually
must refresh the information before using it again.
unavailable
The unavailable is a status used for data center servers and virtual servers.
When a data center server or virtual server is unavailable, the 3-DNS
Controller does not use it for load balancing.
unknown
The unknown status is used for data center servers and virtual servers.
When a data center server or virtual server is new to the 3-DNS Controller
and does not yet have metrics information, the 3-DNS Controller marks its
status as unknown. The 3-DNS Controller can use unknown servers for
load balancing, but if the load balancing mode is dynamic, the 3-DNS
Controller uses default metrics information for the unknown server until it
receives live metrics data.
up
The up status is used for data center servers and virtual servers. When a data
center server or virtual server is up, the data center server or virtual server is
available to respond to name resolution requests.
virtual server
A virtual server is a specific combination of a virtual IP address and virtual
port, and is associated with a content site that is managed by a BIG-IP,
EDGE-FX Cache, or host server.