Table Of Contents

Glossary

A
answer	Individual resource (virtual IP address [VIP], name server [NS], or content routing agent [CRA] that is used to reply to a content request.
answer group	Customer-defined set of virtual IP address (VIP), name server (NS), or content routing agent (CRA) addresses from which an individual answer is selected and used to reply to a content request.

B
boomerang	Server load-balancing component of the Global Site Selector (GSS) that uses calculations of network delay to select the site "closest" to the requesting D-proxy. Closeness is determined by conducting DNS races between content routing agents (CRAs) on each host server. The CRA that replies first to the requesting D-proxy is chosen to reply to the request.

C
client	Content consumer, typically a web browser or multimedia stream player, that makes Domain Name System (DNS) requests for domains managed by the Global Site Selector (GSS).
content provider	Customer that deploys content on a Content Delivery Network (CDN), or purchases hosting services from a service provider or web hosting service.
content router	Machine that routes requests for content through Domain Name System (DNS) records.
content routing agent (CRA)	Software running on a Content Delivery Network (CDN) or server load-balancing device that provides information to a Global Site Selector (GSS) for making content routing decisions, and handles content routing requests from the GSS.
Content Switching Module (CSM)	Server load-balancing component for the Catalyst 6000 Switch product.
Content Services Switch (CSS)	Cisco server load-balancing appliance for Layer 4 through Layer 7 content.
customer	Cisco customer purchasing Global Site Selector (GSS) hardware, software, or services. Typically an Internet service provider (ISP), application service provider (ASP), or enterprise customer.

D
data center	Collection of centrally located devices (content servers, transaction servers, or web caches).
DNS rule	Central configuration and routing concept of the Global Site Selector (GSS), allowing specific request balance resources, methods, and options to be applied to source address and domain pairs.
domain list	One or more hosted domains logically grouped for administrative and routing purposes.
D-proxy	Client's local name server, which makes iterative DNS queries on behalf of a client. A single recursive query from a client may result in many iterative queries from a D-proxy. Also referred to as "local domain name server," or LDNS.

F
fully qualified domain name (FQDN)	Domain name that specifies the named node's absolute location relative to the Domain Name System (DNS) root in the DNS hierarchy.

G
Global Site Selector (GSS)	Cisco content routing device that intelligently responds to Domain Name System (DNS) queries, selecting the "best" content locations to serve those queries based on DNS rules created by the customer.
GSS network	Set of Global Site Selectors (GSSs) in a scaled, redundant GSS deployment.
Global Site Selector Manager (GSSM)	Device that administers a Global Site Selector (GSS) network, storing configuration information and statistics for GSS devices and providing a graphical user interface that GSS administrators use to reconfigure or monitor the performance of their GSS network.
global server load balancing (GSLB)	System based on the Content Services Switch that directs clients through the Domain Name System (DNS) to different sites based on load and availability. Two versions of GSLB currently exist: •Rule-based GSLB •Zone-based GSLB

H
hosted domain	Any domain managed by the Global Site Selector (GSS). A minimum of two levels is required for delegation (for example, foo.com). Domain wildcards are supported.

K
keepalive (KAL)	Periodic testing of availability and status of a content service through the sending of intermittent queries to a specified address using one of a variety of methods. The Global Site Selector product uses both primary keepalive and secondary keepalive IP addresses. See keepalive method.
keepalive method	Protocol or strategy used to determine whether a device is on line, for example, ICMP, KAL-AP, HTTP-Head, and CRA round-trip time.

L
location	Grouping for devices with common geographical attributes, used for administrative purposes only, and similar to data center or content site. See data center.

N
name server (NS)	Publicly or privately addressable Domain Name System (DNS) server that resolves DNS names to IP addresses. Name servers are used by the Global Site Selector (GSS) for name server forwarding, in which queries that the GSS cannot resolve are forwarded to a designated name server that can resolve them.

O
ordered list	List of possible answers that are used for routing. List members are ranked and tried in order. Answers lower on the list are not tried unless all previous members fail to provide a suitable result.
origin server	Machine that serves original or replicated content provider content.
owner	Internal department or resource or external customer associated with a group of GSS resources such as domain lists, answer groups, and so on.

R
region	Grouping of Global Site Selector (GSS) locations with common geographic attributes that is used to organize GSS resources.

S
Secure Socket Layer (SSL)	Industry-standard method for protecting and encrypting web communication.
server load balancer (SLB)	Network device that balances content requests to network resources based on content rules and real-time load and availability data collected from those devices. Server load balancers like the Cisco Content Services Switch (CSS), Content Switching Module (CSM), and LocalDirector provide publicly routable virtual IP addresses (VIPs) while front-ending content servers, firewalls, Secure Socket Layer (SSL) terminators, and caches. Third-party SLBs are supported in a GSS network through the use of Internet Message Control Protocol (ICMP) and HTTP-Head keepalives.
service provider	Cisco customer that provides infrastructure for a Content Delivery Network (CDN). Also ISP (Internet service provider) and ASP (application service provider).
source address list	List of source IPs or source IP blocks that are logically grouped by the system administrator.
static proximity	Type of request routing in which incoming requests from specified D-proxies are routed to statically defined resources that have been identified as being proximal to the source D-proxies.
subscriber	Client or set of clients that is to receive a certain style of DNS routing. Subscribers often pay for application services from the Cisco GSS customer.

T
Time To Live (TTL)	Length of time that a response is to be cached and considered valid by the requesting D-proxy.

W
Web Network Services (WebNS)	VxWorks-based operating system and software that runs on the Content Services Switch (CSS).

Posted: Mon Mar 21 11:03:25 PST 2005
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