Subscriber
A subscriber is typically defined by a unique subscriber identifier to which an assortment of polices (or subscriber profile) can be applied. A subscriber typically (but not always) maps into a VLAN, a VPI/VCI pair, an ‟ifentry” (a logical interface such as a SAP), a (source) MAC or IP address or a physical port, which uniquely identify a billable entity for the service provider.
Subscriber Management
The management of all services, policies, AAA functions and configurations that relate to the concept of a subscriber. Subscriber management can be configured in a variety of ways, but it is critical that subscriber management integrates seamlessly with element and service management across the broadband infrastructure by, for instance, the 5750 Subscriber Services Controller (SSC). Subscriber management can also be implemented through CLI or scripted commands at the platform level, whereby a network administrator would manually configure the set of QoS, security, AAA or anti-spoofing functions that relate to a particular billable entity or subscriber. Subscriber management is typically centralized and highly integrated with the element, services and middleware management functions for streamlined management, flowthrough provisioning, and accelerated service activation, with minimized operating expenditures.
Subscriber Policy Enforcement
The set of actual enforcement functions that are implemented relative to a specific subscriber, possibly at multiple enforcement points in the infrastructure and as a result of a match between the subscriber profile which was defined by the subscriber management suite (5750 SSC) and actual traffic patterns. Examples include for instance, the shaping, policing or rate limiting of traffic or the traffic of a specific subscriber being dropped because it matched or violated any specific rule (packet with a mismatch between MAC and IP address suggesting an address spoof for instance).
Subscriber SAPs — A subscriber SAP is a service access point (SAP) where enhanced subscriber management is active. Enhanced subscriber management must be explicitly enabled on a per-SAP basis with the CLI sub-sla-mgmt command.
A subscriber SAP can be used by a single subscriber or support multiple subscribers simultaneously. Each subscriber can be represented by one or multiple subscriber hosts on the subscriber SAP. If enhanced subscriber management is enabled on a SAP, any configured QoS and IP filter policies defined on the SAP are ignored. A subscriber SAP must refer to an existing subscriber identification policy.
Hosts and Subscribers — A host is a device identified by a unique combination of IP address and MAC address. Typically, the term ‟subscriber host” is used instead of the ‟host”.
A host can be an end-user device, such as a PC, VoIP phone or a set top box, or it can be the user’s Residential Gateway (RGW) if the RGW is using Network Address Translation (NAT).
Each subscriber host must be either statically provisioned or dynamically learned by the system. The host’s IP address plus MAC address are populated in the subscriber host table on the appropriate SAP to allow packets matching the IP address and MAC address access to the provider’s network.
A dynamic subscriber host is dynamically learned by the system through the DHCP snooping or relay process. Each subscriber SAP created on the system is configured (using the lease-populatecommand) to monitor DHCP activity between DHCP clients reached through the SAP and DHCP servers. DHCP ACKs from the DHCP server are used to determine that a specific IP address is in use by a specific DHCP client. This client IP address association is treated by the system as a dynamic subscriber host.
When it is not possible to dynamically learn a subscriber host through DHCP, a static subscriber host can be created directly on a subscriber SAP. Because a subscriber identification policy is not applicable to static subscriber hosts, the subscriber identification string, subscriber profile and SLA profile must be explicitly defined with the hosts IP address and MAC address.
A subscriber (in the context of the router) is a collection of hosts getting common (overall) treatment. It is expected that this group of hosts originate from the same site and all hosts of a subscriber are reached by the same physical path (such as a DSL port).
After a subscriber host is known by the system, it is associated with a subscriber identifier and an SLA profile instance. Subscriber hosts with a common subscriber identifier are considered to be owned by the same subscriber.
Depending on the network model, hosts associated with a single subscriber can be associated with a single subscriber SAP or spread across multiple subscriber SAPs on the same port.