Broadband Network Gateway (BNG)
Broadband Network Gateways (BNG) are an essential part of Customer-VLAN (C-VLAN) based broadband topologies but can also be used in other topologies. The BNG provides service control, for example rate-limiting, packet filtering, and prioritization of traffic, for the subscribers connected to the network.
Waystreams MPC480 Edge Router and ASR6000 Layer3 switch provides BNG functionality that allow operators to deploy a smart network solution that is easy to operate and focus on the end-user experience.
The ASR6000 enables highly distributed BNG features, scaling up to 576 subscribers per switch which makes it perfect to locate close to the access point, DSLAM or other last-mile access used. The more powerful MPC480 Edge Router allows up to 25,000 customers with multiple services to be controlled in each router. This allows the MPC480 to cover a larger access network either in a distributed or centralized location depending on the network size.
Access-networks for broadband services can be built in a number of ways by any variety of access technologies such as GPON, Point-to-point, xDSL and even wireless networks. Using BNGs from Waystream it is possible to build both centralized and distributed topologies and in combination with MPLS to create backhaul and transport services.
In a C-VLAN topology each customer is assigned to a unique VLAN to create traffic separation and isolation in the access. This isolation is maintained as the traffic is backhauled to the BNG. The BNG can be located close to the access in a distributed topology or it can be placed centrally in the network.
In a central deployment, the C-VLANs need to be bridged through the access and core network to reach the BNG. In some topologies such as in metro networks this is kept at layer2 but for a network with an MPLS core, the Waystream solution also supports C-VLANs that are encapsulated into MPLS pseudo-wires with the BNG as one end-point
Static IP topologies
While dynamic assignment of IP addresses often is the preferred option for residential broadband services, there may be situations where this approach is not applicable. Perhaps the customer requires a special service or multiple customers are in the same VLAN where DHCP assignment has been disabled. The Waystream BNG allow services to be assigned to the traffic to/from a specific IP address, regardless of if it has been assigned by static or dynamic configuration.
It is even possible to use RADIUS-based authorization for static IP addresses (see below) which gives operators maximum flexibility and simplified operation to change and update service parameters from their customer database system.
The Waystream BNG supports extensive classification rules to identify traffic to be affected by the service rules. Service rules include packet filtering, rate-limiting (using a variety of technology such as policing and shaping), prioritization etc.
Services can be applied on a physical or logical interface (such as on the C-VLAN) and can also be assigned to a prefix or even individual host in the customer premise.
The MPC480 supports IPv4/IPv6 routing and MPLS, which allows a high degree of flexibility for the transport of service traffic. C-VLANs can be received as bridged ethernet frames as well as by MPLS encapsulation, but it also means that the MPC480 can deliver customer traffic into the core network by MPLS for example as part of an MPLS VPN or pseudo-wire.
These features combined creates market leading flexibility for service providers to define and implement their services.
RADIUS controlled services
The Waystream BNGs are designed to allow configuration of services either through CLI or with RADIUS. Using RADIUS allows a central database to dynamically set and update rate-limiting and other key parameters for individual customers at moment’s notice, and also provides per-service accounting for statistics or even volume based service billing purpose.
The solution uses the concept of a service template - a set of configuration commands to be applied to instantiate a service for a customer. Key parameters can be controlled by RADIUS, and the framework built into the BNGs allow a high degree of customization to allow maximum control by RADIUS of BNG configuration and service options.