Common use of xDSL Clause in Contracts

xDSL. Digital Subscriber Line (DSL) technologies ?? is a collective term for a set of transmission tech- nologies for delivering data services on the access loop. DSL is designed to exploit the installed base of twisted pair telephone copper cable to transport data services. This feature has made DSL commercially attractive to service providers, who use it to provide Internet access, IPTV, VPNs or VoIP to residential and enterprise customer. Figure 12 provides an overview of the different elements in the customer and service provider networks used for delivering data services over DSL. DSL technologies provide connectivity between the home router (Customer Premises Equip- ment, CPE) and the DSLAM (Digital Subscriber Line Access Multiplexer). DSLAMs, usually located at telephone exchanges, connect to multiple customer CPEs, aggregating their traffic and forwarding it to a Broadband Remote Access Server (BRAS) over the providers aggregation net- work. BRASs are a key component of DSL broadband access networks that serve as an aggrega- tion point for subscriber traffic (IP, PPP and ATM) and provide session termination and subscriber management functions such as authentication, authorization, accounting (AAA), and IP address assignment. Figure 13 depicts the protocols that are typically used to provide data services over DSL. The CPE is physically connected to the DSLAM via the twisted pair copper cable; that is where DSL physical layer provides its service. ATM was traditionally layered on top of DSL, since DSLAMs typically operated over ATM aggregation networks. Today service providers are converging to- wards Ethernet aggregation using Carrier Ethernet solutions, therefore DSLAMs have evolved to support Ethernet uplinks instead of ATM ones. Host Home 1 Host Home 2 Host Home N Customer network Local loop Aggregation Provider network Assuming Ethernet is used at the providers metropolitan aggregation network, 802.1q or 802.1ad over other protocols (refer to the Aggregation section of this document) is used to in- terconnect the DSLAM with the BRAS. The CPE needs to run a Point to Point Protocol over Ethernet (PPPoE) session against the BRAS, so that the BRAS can authenticate each individual customer and assign one or more IP addresses to it depending on the services it has purchased from the provider (Internet access, VoIP, etc.). EAP, the Extensible Authentication Protocol, is normally used to carry out authentication, usually through the interaction with a Radius server. Once authenticated, the customer traffic is routed via the providers core to its final destination (other customers on the provider network, the Internet, etc.)

xDSL. Digital Subscriber Line (DSL) technologies ?? is a collective term for a set of transmission tech- nologies for delivering data services on the access loop. DSL is designed to exploit the installed base of twisted pair telephone copper cable to transport data services. This feature has made DSL commercially attractive to service providers, who use it to provide Internet access, IPTV, VPNs or VoIP to residential and enterprise customer. Figure 12 provides an overview of the different elements in the customer and service provider networks used for delivering data services over DSL. DSL technologies provide connectivity between the home router (Customer Premises Equip- ment, CPE) and the DSLAM (Digital Subscriber Line Access Multiplexer). DSLAMs, usually located at telephone exchanges, connect to multiple customer CPEs, aggregating their traffic and forwarding it to a Broadband Remote Access Server (BRAS) over the providers aggregation net- work. BRASs are a key component of DSL broadband access networks that serve as an aggrega- tion point for subscriber traffic (IP, PPP and ATM) and provide session termination and subscriber management functions such as authentication, authorization, accounting (AAA), and IP address assignment. Figure 13 depicts the protocols that are typically used to provide data services over DSL. The CPE is physically connected to the DSLAM via the twisted pair copper cable; that is where DSL physical layer provides its service. ATM was traditionally layered on top of DSL, since DSLAMs typically operated over ATM aggregation networks. Today service providers are converging to- wards Ethernet aggregation using Carrier Ethernet solutions, therefore DSLAMs have evolved to support Ethernet uplinks instead of ATM ones. Host Home 1 Host Home 2 Host Home N DRAFT Customer network Local loop Aggregation Provider network Assuming Ethernet is used at the providers metropolitan aggregation network, 802.1q or 802.1ad over other protocols (refer to the Aggregation section of this document) is used to in- terconnect the DSLAM with the BRAS. The CPE needs to run a Point to Point Protocol over Ethernet (PPPoE) session against the BRAS, so that the BRAS can authenticate each individual customer and assign one or more IP addresses to it depending on the services it has purchased from the provider (Internet access, VoIP, etc.). EAP, the Extensible Authentication Protocol, is normally used to carry out authentication, usually through the interaction with a Radius server. Once authenticated, the customer traffic is routed via the providers core to its final destination (other customers on the provider network, the Internet, etc.)