Service providers continue to drive the need for a predicable and manageable network infrastructure. But cost can be a significant factor in adoption of any technology (see MPLS). Demanding the low per-bit delivery cost of Ethernet with the dependability of circuit-based networks has led to the development of PBB-TE (provider backbone bridging with Traffic Engineering).
To provide the predictability and performance associated with circuit based networks, spanning tree protocol is disabled and manual provisioning of forwarding paths are required. 802.1ah (provider backbone bridging) is used to wrap incoming traffic in the provider’s packet header. This isolates customer traffic and associates routing and QoS information with the data. Initially, network operators have shown interest in utilizing PBB-TE in two applications:
Instead of taking on the complexity of MPLS in their core network, some operators are exploring the usefulness of provisioning pathways (trunks) across the core network using PBB-TE. In carrier core networks, little dynamic capability is required; instead, the control of each byte of traffic, and the ability to bill for it, make a manually provisioned environment acceptable.
The second application where PBB-TE is being used is at the edge of the network. Instead of using MPLS to the edge (and raising cost), or attempting to use rudimentary VLAN’s to accomplish traffic management, operators are exploring the use of PBT to provide a circuit like connection to individual customers. PBB-TE can help provide discrete traffic management and enforce quality of service profiles.
