Internet traffic continues to grow at an explosive rate with the number of users doubling each year. This unsurpassed growth is increasing the demand for higher capacity interfaces from OC3/STM1 to OC48/STM16. In addition, Packet-Over-SONET/SDH (POS) enables efficient transport of IP traffic and uses SONET/SDH concatenated payloads (i.e. STS-3c/VC-4, STS-12c/VC-4-4c or STS-48c/VC-4-16c) to achieve a higher order of statistical multiplexing. At present, concatenated services at VC-4 rates are only available in some parts of the world (for example Europe), with higher rates not yet readily available. The Cisco 12000 Series 1-Port Channelized OC-12/STM-4 (OC-3/STM-1) Line Card provides customers in these areas with an STM-4 POS interface which can be provisioned through the legacy network.