CISCO PA-POS-1OC3, CNUIAHFAAA, 73-9562-01, 800-25485-01 SFP Cisco 1 Port Packet/SONET OC3C/STM1 Port Adapter
The PA-POS-1OC3 provides a single Packet-over-SONET (POS) port in a single port adapter slot. The port functions as a single independent OC-3c/STM1 port. The PA-POS-1OC3 is used as a direct connection between the supported router or switch platform and an external network.
The PA-POS-1OC3 fits into a single port adapter slot on the Cisco 7201 router, Cisco 7204VXR router, Cisco 7206VXR router, Cisco 7301 router, Cisco 7304 PCI port adapter carrier card in Cisco 7304 router, the 7401ASR router, Cisco 7500 series routers (Cisco 7505, Cisco 7507, Cisco 7513), and Cisco 7600 series routers (Cisco 7603, Cisco 7606, Cisco 7609, Cisco 7613) with FlexWAN or Enhanced FlexWAN.
The POS specification addresses the use of PPP encapsulation over SONET/Synchronous Digital Hierarchy (SDH) links. SONET is an American National Standards Institute (ANSI) standard (T1.105-1988) for optical digital transmission at hierarchical rates from 51.840 Mbps (STS-1) to 2.5 Gbps (STS-48) and greater. SDH is the international standard for optical digital transmission at hierarchical rates from 155.520 Mbps (STM-1) to 2.5 Gbps (STM-16) and greater.
Because SONET/SDH is by definition a point-to-point circuit, PPP is well suited for use over these links. PPP was designed as a standard method of communicating over point-to-point links.
SONET is an octet-synchronous multiplex scheme that defines a family of standard rates and formats. The basic rate for POS is that of STS-3c/STM-1, which is 155.520 Mbps. The available information bandwidth is 149.760 Mbps, which is the STS-3c/STM-1 Synchronous Payload Envelope (SPE), the payload portion of the SONET frame into which the octet-oriented user data is mapped. (Octet boundaries are aligned with the SPE octet boundaries.) For the SPE with the PA-POS-1OC3, section, line, and path overhead are removed.