GFAST™ Gigabit Ethernet/PON

The latest additions to Nebula’s family of EtherOptic products are the GFAST Gigabit Ethernet/PON system and the GFAST Fractional Gigabit Ethernet system. Built on Nebula’s proven EtherOptic platform, these systems incorporate passive optical networking technology to deliver reliable, cost-effective solutions for next-generation business Ethernet and consumer broadband services.

GFAST GigE/PON offers two systems choices designed to support service providers' differing deployment needs. 

• Point-to-Multipoint Upgrades Existing Ethernet Service Delivery
  
  The GFAST Fractional Gigabit Ethernet system lets service providers with existing business Ethernet services incorporate point-to-multipoint options to increase available Ethernet service bandwidth, fiber utilization and service density. Service providers can multiplex up to 32 customers onto a single fiber increasing capacity of existing fiber to support more customers or high-bandwidth services.
   
• Multidrop PON Supports Incremental Broadband Service Deployment
  
  The GFAST GigE/PON system lets service providers deploy FTT Home or FTT Node in a multidrop configuration,  supporting up to 32 customers on a single fiber with neighborhood connections.

Conserve Energy and Space with High Density
A high-density solution designed to meet carrier operating requirements, the GFAST Fractional GigE system can be multiplexed in the central office, at the customer premise, or with a multidrop configuration to multiple locations. It supports up to 640 customers on a single Nebula EtherOptic CO shelf.

Carry Business and Consumer Traffic
The GFAST Optical Line Terminal (OLT) and Optical Network Unit (ONU) are designed to GigE/PON standards and offer service providers a reliable, cost-effective way to build out an optical infrastructure for Ethernet/IP-based services. In addition, the GFAST GigE/PON system uniquely incorporates industrial strength bidirectional encryption, making it suitable for secure communications. This unique feature allows service providers to serve business and consumer customers on the same fiber, a critical advantage in ensuring profitability.

Define a Wide Range of Services
The GFAST system supports a broad range of IP services, such as secure VLAN and voice-over-IP for business customers, and video, IPTV and broadband internet access for consumers with rich traffic shaping and Quality of Service (QoS) features, including

• Traffic marking, classification and shaping operate on eight QoS queues per customer, supporting different service offerings on the same fiber.
  
• Automatic bandwidth sharing across queues (and customers) supports services with guaranteed service quality, guaranteed minimum bandwidth, and bursting up to available capacity. 
  
• Two-way encryption transforms PON technology into a viable solution for business services.

The GFAST GigE/PON family uses the proven Nebula EtherOptic platform, broadly deployed today in major carrier networks for Ethernet delivery.  Designed with carrier deployment and operations needs in mind, the Nebula EtherOptic platform provides

• Incremental provisioning to support profitable growth, where capital spending takes place in response to customer orders
• Addition of individual line cards to the EtherOptic shelf without disrupting existing services
• Easy integration into existing management systems for operations and service support

Rich Broadband Service Offerings

The GFAST GigE systems have sophisticated Quality of Service (QoS) and traffic shaping features that give service providers the granular control necessary to offer a broad range of communication, information and entertainment services. Service providers can take advantage of the advanced bandwidth sharing features to ensure optimal bandwidth utilization and offer ‘bursting’ options to customers. For example, best-effort services can be policed to maximum bandwidths, while high-priced services are allowed extra bandwidth when available, and voice services are guaranteed to receive the required bandwidth and immediate, low-latency forwarding.

Secure IP Services—Recent investigation has identified that simple downstream encryption is insufficient to prevent eavesdropping and masquerading by coresident ONUs. The GFAST platform employs bidirectional encryption to ensure all communication is secure.

Traffic Queues—All traffic for each customer is classified and queued into a set of eight buffers, per customer, according to the QoS classification of the traffic. Priorities can be set for each queue.

Bandwidth assignment and sharing—The GFAST system assigns bandwidth based on a subscription-time variable. Bandwidth sharing can be enabled or disabled for each queue. Bandwidth is allocated with a weighted round robin (WWR) servicing algorithm that guarantees minimum bandwidth to each Class of Service. When there is no congestion, minimum bandwidth is not policed and any queue can use available bandwidth.

Optimal bandwidth use is further supported by frame splitting and early discards. Early discard enables protocols such as TCP to converge to the full available bandwidth. Downstream traffic is switched to the right customer based on an internal VLAN tag in each frame. The GFAST OLT manages upstream bandwidth, allocating it in 6-kilobyte windows to each GFAST ONU. The ONU can split customer frames across multiple windows, ensuring that all of the allocated bandwidth is usable. Traffic shaping is implemented in hardware for maximum throughput and minimum latency.

QoS—Many different QoS configurations are possible. For each QoS, the traffic is at first shaped, and then policed to the subscribed bandwidth for that QoS. WWR queue servicing ensures that the GFAST Fractional GigE network delivers high-priority traffic immediately, without starving lower-priority traffic.

Designed for Carrier-Grade Operations

The GFAST GigE systems are designed on the Nebula EtherOptic platform, which has been in use in carrier networks for more than a decade. Nebula has evolved the EtherOptic platform to meet carriers’ demanding operational requirements while keeping the system highly affordable. Operations features support easy, nonintrusive deployment, upgrade and management.

Deploy and Configure—The GFAST OLT and ONUs are configured using a Telnet or SSH session. Commands configure the QoS features and other network modes and parameters, including the associated packet types, the bandwidth, and buffer depth. The devices can be reconfigured while in operation, ensuring that changes to one customer’s service do not cause downtime for others. Upgrading the unit’s software can be done remotely, eliminating truck rolls and meeting the combined goals of sustainability and reduced service support costs.

Management—The GFAST OLT and ONU are SNMP-managed devices. The management system in each is reached by using a VLAN number on the service provider’s interface. Statistics are kept for both the Ethernet interface and individual queues. Devices can be queried for status and to download statistics.

Reliability—The GFAST OLT has two Ethernet interfaces, one of which can be configured to provide automatic failover in the event that the equipment connected to the primary interface fails.