Cisco 7300-2OC12POS-SML : 2-port OC12 POS line card for Cisco 7304 w/ Single-mode LR

The OC12 POS line cards provide the Cisco 7304 router with single or dual 622.080-Mbps POS interfaces on a single card. You must use the appropriate optical fiber cables to connect the OC12 POS line card with an external OC-12 network.

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 (T1.1051988) for optical digital transmission at hierarchical rates from 51.840 Mbps (STS-1) to 622.080 Mbps (STS-12) and greater. SDH is the international standard for optical digital transmission at hierarchical rates from 155.520 Mbps (STM-1) to 2.488 Gbps (STM-16) and greater.

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.)