Chapter 43: BSoD L2VPN
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
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Background Information
The following paragraph from the DOCSIS BSoD specification is a description of the background and business application of
this feature:
Data networking between the multiple sites of commercial businesses represents a significant business opportunity for
cable operators. Commercial data networks are usually implemented with private point-to-point data connections such
as Frame Relay, ISDN, or ATM virtual circuits, often with equipment that provides transparent delivery of layer 2
Ethernet LAN packets. A service that interconnects subscriber enterprise LANs with Layer 2 forwarding is called
Transparent LAN Service (TLS).
(Data-Over-Cable Service Interface Specifications Business Services over DOCSIS®, Layer 2 Virtual Private Networks, CM-
SP-L2VPN-I08-080522, May 22, 2008.)
This same specification goes on to explain that a TLS can be created using BSoD. From the point of view of the business
enterprise using BSoD, the TLS may include CPE from more than one CMTS in the cable operator’s network, other LANs
attached to CMs, and any other LANs bridged to the customer’s VLAN in the IEEE 802.1Q-compliant bridge in the cable
operator’s backbone. The CPE in the TLS can be managed or operated just as if they were on a private Ethernet LAN, with
IP addresses assigned by the TLS enterprise and taken from its subnet. The IP subnet of the TLS does not need to be
coordinated with the enterprise clients or customers on the cable side of the TLS. Finally, the LAN subscribers in the TLS
are isolated from the other customers in the cable operator’s HFC network(s) and from other L2VPNs.
