Cisco Technology, Inc.

Manigandan Boopalan

Prashant Anand

Sudhir Kayamkulangara

Dinuraj K

Manoj N Kumar

Joel Richard Goergen

Rohit Dev Gupta

Mehmet Onder Cap

Damaruganath Pinjala

Manoj Kumar

Manjunatha Reddy Shivashankara

Sandeep Mehdiratta

Luca Della Chiesa

Arjun Guzar Jayaprakash

Jatin Kohli

Prashanth Pavithran

Parag Ghate

A rack-mountable heat-exchanger for modular electronic systems is provided that include a heat exchanger including ambient air inlets and outlets forming an ambient airflow path in a first direction, and recirculating air inlets and outlets forming a recirculating airflow path in a second direction perpendicular to the first direction separated from the ambient airflow path; housing for an electronic device, the housing including internal air inlets and outlets forming an internal airflow path; a first duct configured to link the recirculating air outlet to the internal air inlet; a second duct configured to link the recirculating air inlet to the internal air outlet; and fan assemblies located one of the airflow path, configured to propel air through the heat exchanger in the respective airflow path.

Rack-mountable heat-exchanger for modular electronic systems

Techniques associated with link establishment in a fronthaul network are described herein. In one embodiment, a method includes receiving, by a proxy node, a Common Public Radio Interface (CPRI) bit stream transmitted by a radio equipment controller, wherein the CPRI bit stream is transmitted within a transmit time interval of the radio equipment controller; and fast-sampling, by the proxy node, the CPRI bit stream to determine whether a hyper frame number synchronization with the radio equipment controller at a common matching link bit rate is achievable, wherein the fast-sampling comprises attempting to decode the received CPRI bit stream and achieve the hyper frame number synchronization for each of a plurality of link bit rates configured for a fast-sampling time period during at least one fast-sampling time interval configured for the proxy node.

Link establishment between a radio equipment controller (REC) and radio equipment (RE) in a fronthaul network

Techniques that provide link establishment between a radio equipment controller (REC) and a radio equipment (RE) in a fronthaul network are described herein. In one embodiment, a method includes performing, Common Public Radio Interface (CPRI) Layer 1 (L1) link auto-negotiation operations to establish a CPRI link between the REC and RE. A proxy slave may achieve a hyper frame number (HFN) synchronization with the REC at a link bit rate for a first CPRI bit stream and communicate the first CPRI bit stream and the link bit rate to a proxy master. The proxy master may communicate a second CPRI bit stream to the proxy slave to transmit to the REC. The L1 link auto-negotiation operations are completed and CPRI link is established between the REC and the RE when the REC achieves a HFN synchronization for the second CPRI bit stream.

In one embodiment, an apparatus includes a chassis base, a printed circuit board mounted on the chassis base, a heatsink positioned over the printed circuit board to prevent corrosion of components on the printed circuit board, wherein the heatsink comprises a plurality of upward extending fins and a plurality of downward extending walls, a seal interposed between an edge of the downward extending walls and the chassis base, and a cover extending over the heatsink.

Corrosion preventive heatsink for network device

In a fronthaul network system, when a CPRI link fault is detected at either of the REC or RE, both the REC and RE perform a Layer 1 synchronization. The fault may be a loss of signal, loss of frame, or a line code violation, which also translates to a loss of signal if seen beyond a threshold. A proxy slave recognizes the fault in a CPRI signal from a first radio device and inserts the fault alarm into a header of a radio over Ethernet frame. The proxy slave continues to communicate the signal for a configured number of hyper-frames. A proxy master receives the signal and communicates the signal and the fault alarm to a receiving radio device for a configured number of hyper-frames. The proxy and radio devices all perform a joint resynchronization.

Link fault handling in fronthaul communication networks

Techniques that provide link auto-negotiation between a radio equipment controller (REC) and a radio equipment (RE) are described herein. In one embodiment, a method includes performing, by a proxy master, a Common Public Radio Interface (CPRI) Layer 1 (L1) link auto-negotiation with a RE to achieve a L1 synchronization between the proxy master and the RE at a link bit rate; communicating the link bit rate from the proxy master to a proxy slave; performing, by the proxy slave, a CPRI L1 link auto-negotiation with a REC to determine whether a L1 synchronization between the proxy slave and the REC is achieved, wherein if the L1 synchronization is achieved, the link bit rate is a common matching link bit rate achieved; and upon the common matching link bit rate being achieved, establishing a CPRI link between the REC and the RE using the common matching link bit rate.

Link auto-negotiation between a radio equipment controller (REC) and radio equipment (RE) in an ethernet-based fronthaul network

Techniques are described to provide for state machine handling at a proxy node in an Ethernet-based fronthaul network. In one example, a method includes performing, by a proxy node of a fronthaul network, negotiation operations associated with establishing a Common Public Radio Interface (CPRI) communication link between radio devices of the fronthaul network, wherein the negotiation operations comprise Layer 1 synchronization operations and Radio over Ethernet (RoE) validation operations for one or more link bit rates; and facilitating communications between the radio devices at a matching link bit rate upon completion of the negotiation operations.

State machine handling at a proxy node in an Ethernet-based fronthaul network

Techniques are described to provide for re-timing a packetized radio flow to clean noise induced by packet delay variation of a packet network. In one example, a method includes receiving, at a first node of a fronthaul network, a Radio over Ethernet (RoE) frame transmitted by a second node in which the RoE frame comprises a Common Public Radio Interface (CPRI) bit stream associated with a first radio device, a sequence number, and a first time stamp. The method may further include generating a second time stamp by the first node upon obtaining the RoE frame; calculating an induced delay value based, at least in part, on the first time stamp and the second time stamp; calculating a re-timing value based on a re-timing interval and the induced delay value; and transmitting the CPRI bit stream to a second radio device based on the re-timing value.

Growing community of inventors

Bengaluru, India

Manigandan Boopalan