Broadband access server

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With Broadband Remote Access Server ( BRAS ) or broadband PoP ( Point of Presence ) network elements of broadband networks such as DSL and UMTS called. They are part of the network of an Internet Service Provider (ISP) and feed the data traffic of the end-user connections into the backbone network. BRAS are also known as Broadband Network Gateway ( BNG ).

The tasks of a BRAS include:

  • Aggregation of data traffic from the access points (mostly DSLAMs )
  • Termination of PPP sessions or IP over ATM sessions. A BRAS can terminate approximately 50,000 simultaneous PPPoE sessions.
  • Enforcement of guarantees and limitations in the context of Quality of Service

In DSL networks, DSLAMs collect the data traffic of the locally connected subscribers and forward it via an ATM or IP network (the so-called concentrator network or concentration network ) to the BRAS, which in this case also acts as a DSL Access Concentrator ( DSL-AC ) referred to as.

The BRAS forms the logical end point of PPP sessions. This can be PPP over Ethernet (PPPoE) or PPP over ATM (PPPoA). The BRAS is responsible for assigning session parameters such as IP addresses. It is therefore connected to an authentication, authorization and accounting system ( AAA ) at the rear . Since it is a router , the BRAS is the first visible hop between the customer and the internet.

Deutsche Telekom's old DSL access network with 74 locations was initially set up with BRAS of the type ERX-1410 from Juniper Networks and Cisco 6400, which were later replaced by ERX-1440. The VDSL network of Deutsche Telekom is set up with BRAS of the type Cisco 10008 and Ericsson SE800.

Current developments

The currently existing base of BRAS and DSLAMs from the early days of DSL networking is rather unsuitable for new services such as IPTV and IP telephony , as these services have expanded multicast and quality-of-service requirements. One possible solution is to implement BRAS and DSLAM in a common device.

In the current (2016) network architecture, Deutsche Telekom is expanding 899 locations for around 2000 Juniper MX960 BNGs.


  • Remco van der Velden: Competition and cooperation on the German DSL market - economics, technology and regulation , Mohr Siebeck Verlag, Tübingen 2007. ISBN 3-16-149117-3

Individual evidence

  1. Usenet posting with DTAG-BRAS locations at Google Groups
  2. Deutsche Telekom's T-Online to Offer High-Definition IPTV Service over Cisco IP Next-Generation Network ( Memento from May 20, 2011 in the Internet Archive ), press release on the T-Home network at Cisco Systems
  3.  ( page no longer available , search in web archives )@1@ 2Template: Dead Link /
  4. Whitepaper "Understanding DSLAM and BRAS Access Devices" ( Memento of the original from May 15, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 828 kB) from Agilent Technologies  @1@ 2Template: Webachiv / IABot /
  5. WIK-Consult - Adaptation of the broadband cost model to the introduction of the BNG architecture - as of May 9, 2016 - BNetzA