Broadband Subscriber Management Edge Router Overview

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The edge router is the demarcation point between the residential broadband access network and the core network. The Juniper Networks MX-series router (along with the Juniper Networks EX-series Ethernet Switch) can play multiple roles as an edge router. The most common include the following:

Broadband services router (BSR)—This router supports high speed Internet access along with several other subscriber-based services including VoIP, IPTV, and gaming.
Video services router (VSR)—The video services router capabilities are a subset of those provided by a broadband services router. In general, using the MX-series router as a video services router provides bi-directional traffic destined for the set-top box (STB). This traffic includes IPTV and video on demand (VoD) streams as well as associated control traffic such as IGMP and electronic program guide (EPG) updates.

You can also use the MX-series router in certain Layer 2 solutions. For information about configuring the MX-series router in Layer 2 scenarios, see the MX-series Layer 2 Configuration Guide or the MX-series Solutions Guide.

Broadband Services Router Overview

A broadband services router is an edge router that traditionally supports primarily Internet-bound traffic. This router replaces and provides a superset of the functionality provided by a Broadband Remote Access Server (B-RAS). The broadband services router functions can be broken into two key areas—high speed Internet access and IPTV support.

High-Speed Internet Access Support

The broadband services router communicates with the RADIUS server to enforce which services each subscriber can access. For example, one subscriber might have signed up for a smaller Internet access service of 1 Mbps where another subscriber might have signed up for a higher, 10 Mbps service. The broadband services router manages the traffic to each subscriber, ensuring that each subscriber obtains the level of access service they have purchased, while also ensuring that any VoIP traffic receives priority. The broadband services router also makes traffic forwarding decisions based on aggregate bandwidth detected on any adjacent Multiservice Access Node (MSAN).

IPTV Support

The broadband services router supports IPTV traffic including support for IGMP multicast group start and stop requests from downstream MSANs. The broadband services router manages the bandwidth allocations associated with high-bandwidth IPTV as well as video on demand (VoD) traffic to ensure high quality service delivery.

Video Services Router

When configuring a multiedge network, you can use the MX-series router as a video services router (VSR) to support only video traffic without supporting the high-speed Internet access (HSIA) capabilities.

Note: We recommend a single-edge network model but the MX-series router allows for flexibility when defining a multiplay network topology.

Some advantages of using a separate video services router for video traffic include the following:

Provides the ability to add IPTV service without the need to modify an existing edge router that is performing other functions.
Reduces network bandwidth by moving the video edge further out to the network edge while still allowing for centralized broadband services router operation.
Typically requires less capital investment because the video services router does not need to provide per-subscriber management.

Services Router Placement

Depending on the type of network you are creating—single edge or multiedge—you can place a broadband services router or video services router in various locations.

Single Edge Placement

In a single edge network, you use only broadband services routers because the single device must perform all of the necessary edge functions—providing subscriber management for high-speed Internet access and IPTV services. You can use the two following topology models when placing the broadband services router:

Centralized single edge—The edge router is centrally located and placed at one location to cover a particular region. A secondary router is sometimes placed in this location to act as a backup. Downstream MSANs are connected to the broadband services router using a ring or mesh topology.
Distributed single edge—The edge router is placed further out into the network, typically in the central office (CO) closest to the subscribers it services. Downstream MSANs are typically connected directly to the broadband services router (in a true, single edge topology) or through an Ethernet aggregation switch.

In general, the addition of IPTV service favors a more distributed model because it pushes the need for subscriber management farther out into the network.

Multiedge Placement

In a multiedge network, you use both broadband services routers and video services routers. The broadband services router controls any high-speed Internet traffic and the video services router controls video traffic. You can use the two following topology models when placing service routers in a multiedge network topology:

Co-located multiedge—The broadband services router and video services router are housed in the same location and an Ethernet switch directs traffic in the CO to the appropriate edge router.

Note: A single MX–series router can serve as both Ethernet switch and video services router. For information about configuring the MX-series router in Layer 2 scenarios, see the MX-series Layer 2 Configuration Guide or the MX-series Solutions Guide.

Split multiedge—The video services router and broadband services router reside in different locations. In this model, the broadband services router is typically located more centrally and video services routers are distributed.