"The value proposition of Carrier Ethernet is its simplicity and favorable economics."

Mike Adams, VP, Nortel

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Telecom Backplanes

Telecom Load Distribution

Using FocalPoint in Carrier Ethernet Systems

Carrier Ethernet (CE) is emerging as a new low-cost transport mechanism that can replace SONET-SDH in backbone and access networks. It does this by provisioning point-to-point tunnels with redundant paths and fast fail-over capability. But it must also provide Quality of Service (QoS) mechanisms in order to enable service level guarantees for traffic such as voice, video and storage. Although CE shares basic packet transport functions with traditional Ethernet switches, significant feature enhancements must be added to these devices in order to provide CE services. FocalPoint provides these features and can be used in various parts of the Carrier Ethernet network as shown in the figure below.

The Provider Network uses 802.1ad (Q-in-Q) to encapsulate and transport packets using unique VLAN ID's in order to isolate customer traffic. It also uses the VLAN priority field to differentiate services such as voice, video and data. The Carrier Network uses 802.1ah (MAC-in-MAC) to encapsulate and transport provider packets using unique MAC addresses and VLAN tags to isolate and differentiate traffic. An alternative approach is to use T-MPLS to transport traffic through the Carrier Network.

In the example system above, traffic can be switched locally within the FM3212 access switch or through the FM3224 switch module. The FM3224 can also forward data to other local systems through the RTM or to the Carrier Network through the PBB/PBT processing card. In the Provider Network, FocalPoint can provide Q-in-Q encapsulation for local traffic. Through the Carrier Network, traffic can be encapsulated using MAC-in-MAC or T-MPLS in the PBB/PBT processing card.

For optimal performance, the FM3000 devices implement a shared memory structure using egress queuing. FocalPoint provides significant cross-connect bandwidth, which eliminates the congestion that can be found in input-output queued switch devices when deploying services such as multicast. The FocalPoint egress queues provide advanced scheduling options such as strict priority, minimum bandwidth and traffic shaping. Both class-based pause frames and Virtual output queue Congestion Notification (VCN) frames can be used to differentiate up to 8 traffic classes, and provide lossless data transport with low latency and jitter. In addition, flow based policing and shaping can be applied so that traffic flows can be optimized for long haul transmission. Also, the FM3224 can be configured to detect OAM frames and automatically redirect them to a management CPU for processing.

Low Cost 1U System

FocalPoint can also act as the center of a low cost Carrier Ethernet aggregation switch as shown in the figure below. In this example, 40 1GbE ports are aggregated into four 10G OTN uplinks for backhaul transport. With the integration levels achieved by FocalPoint and by other CE standard products in the industry, this entire switch can be implemented today in a cost effective 1U platform.