Enterprise Hierarchy
In the enterprise model, a subscriber is an individual physical access line managed via the EASP over which services are delivered by the service provider. Residential subscribers are described in SDX Objects Guide, Chapter 3, Services and Sessions. In the enterprise, the SDX software supports the organization of the enterprise in the following hierarchy (Figure 28):
- Enterprise - the business itself as a customer of the service provider; for example, the XYM Corporation. An enterprise can have its own set of subscriptions over a physical access line.
- Site - one or more locations, physical or virtual, within the enterprise that share service subscriptions and physical access to services and that are each managed as a unique entity. For example, the XYM Corporation might have a site in Boston and a site in Toronto. Each of these sites can have its own set of subscribed services.
- Access line - a physical access line (usually within a site) from the customer to the service provider's router; the router is configured to access the SDX environment and the Internet and/or the customer's network-based VPN. An access line can have its own set of subscribed services.
Enterprise IT managers can use the EASP to manage interfaces connecting enterprise sites to the network. These interfaces can be leased-line connections or authenticated PPP and DHCP connections.
Figure 28 shows an enterprise hierarchy.
Sites and access lines are subordinate to an enterprise; the enterprise is sometimes said to contain sites and access lines. Access lines are subordinate to a site; the site contains access lines.
In Figure 28, The XYM Corporation enterprise contains two subordinate sites, Boston and Toronto. The Boston site contains a single subordinate access line, while the Toronto site contains two subordinate access lines. All three access lines connect to an router in the service provider network. An individual access line might be a T1 line running PPP or a T3 line running Frame Relay, for example.
Subscription Hierarchy
The different organizational levels of the enterprise receive subscribed services in a hierarchical manner. That is, the subscriptions are available hierarchically. The availability of a subscription to a higher level affects its availability to a lower level.
- Access line - subscriptions apply to a given access line that connects the enterprise to the service provider's network.
- Site - subscriptions apply to all access lines grouped within a site.
- Enterprise - subscriptions apply to all sites and all access lines across the enterprise.
Subscriptions are said to be inherited from a higher level. Access lines inherit subscriptions from sites and the enterprise; sites inherit subscriptions from the enterprise. Figure 29 illustrates a sample enterprise subscription hierarchy. The XYM Corporation subscribes to e-mail, HTTP, and FTP services. Site Boston subscribes to the VoIP and Gold metered services. Finally, site Toronto subscribes to the Silver metered service.
In addition to its individual subscriptions, site Boston inherits subscriptions to e-mail, HTTP, and FTP services from XYM Corporation. Likewise, in addition to its individual subscription, site Toronto inherits subscriptions to e-mail, HTTP, and FTP services from XYM Corporation.
Toronto is not subordinate to Boston, so in this example it is not subscribed to the VoIP and Gold metered services that Boston receives.
Inheritance of subscriptions is a one-way function. A higher-level entity does not have a subscription to services merely because a subordinate entity is subscribed to those services. In the example above, even though sites Boston and Toronto are both subordinate to enterprise XYM Corporation, XYM Corporation does not inherit service subscriptions from either of the sites.