Data Sheet

Packet OC-3 Interface Processor

With the new Packet OC-3 Interface Processor for Cisco 7500 and 7000/RSP series routers, Cisco offers industry-leading broadband data interface bandwidth to support the most demanding applications across both local-area and wide-area networking environments. -Operating at 155 Mbps, the Packet OC-3 interface provides the highest available interface bandwidth for packet-based traffic and is completely compatible with SONET and Synchronous -Digital -Hierarchy (SDH) -network facilities. By using standard packet -protocols with -efficient overhead structures, the Packet OC-3 Interface Processor -maximizes data throughput and line utilization for ex-pensive, high-bandwidth facilities.

Figure 1.: Highest Available Interface Bandwidth for Packet-Based Traffic

In 1991, Cisco pioneered the packet-based High-Speed Serial Interface (HSSI^®) to meet the need for high-speed data transport over 45-Mbps DS-3 facilities. Over the last five years, carriers worldwide have invested heavily in SONET/SDH equipment, making SONET/SDH the most widely deployed broadband networking technology. And over the same period the bandwidth requirements of data applications have grown dramatically. The new Packet OC-3 interface now enables these broadband data applications to efficiently access this extensive -broadband transport infrastructure. Equipped with OC-3 interfaces, packet-based networking equipment can match the interface bandwidths -supported by Asynchronous Transfer Mode (ATM) while providing much higher bandwidth efficiencies.

In wide-area networking applications, the Packet OC-3 interface can directly connect to both carrier and private SONET and SDH facilities. SONET/SDH facilities often provide the most reliable transport, because they can be configured based on dual counter-rotating ring topologies. In local-area networking, Packet OC-3 interfaces can be used to provide direct broadband links between routers in a campus or building without the need for an intermediate switch.

Cisco's Packet OC-3 Interface Processor provides a single OC-3 155-Mbps port and is available with either single-mode or multimode interfaces. Packet data is transported using Point-to-Point Protocol (PPP) and is mapped into the STS-3c/STM-1 frame. The Packet OC-3 interface is compliant with RFC 1619, "PPP over SONET/SDH," and RFC 1662, "PPP in HDLC-like Framing." The encapsulations used apply only seven bytes of transport overhead per frame, which is less than half of that involved with ATM using ATM adaptation layer 5 (AAL5) and line card control (LCC) Subnetwork Access Protocol (SNAP) encapsulations. The Packet OC-3 Interface Processor can operate in any Cisco 7500 series or Cisco 7000 series system equipped with a Route Switch -Processor (RSP). In Cisco 7000 series routers, the Packet OC-3 interface processor can access the -system's CxBus; in Cisco 7500 series systems it can utilize the full -gigabit-per-second bandwidth provided by the Cisco 7500 CyBus.

The Packet OC-3 Interface Processor operates on a version of the Cisco Internetwork Operating System (Cisco IOS) software that will support distributed switching and distributed services capabilities.

Features

Standards-compliant SONET/SDH interface
Supports full-duplex operation at 155 Mbps
Intermediate reach optical interface with single-mode fiber
Optical interface with multimode fiber
Supports SONET/STS-3c and SDH/STM-1 framing and signaling overhead
Online insertion and removal (OIR), enabling users to remove, add, or replace interface processors on line
16 to 64 Mbytes of onboard packet and program memory to support transmit and receive buffering
Software download capability optimizes operation across long -distance links and reduces management costs by enabling remote administration