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Method for resource management for offloaded TCP/IP connections

IP.com Disclosure Number: IPCOM000019986D
Publication Date: 2003-Oct-15
Document File: 2 page(s) / 64K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for resource management for offloaded TCP/IP connections. Benefits include improved functionality, improved performance, and improved support for future technology.

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Method for resource management for offloaded TCP/IP connections

Disclosed is a method for resource management for offloaded TCP/IP connections. Benefits include improved functionality, improved performance, and improved support for future technology.

Background

         In recent years, the increase in network bandwidth has outpaced Moore’s Law. In a conventional host-based TCP/IP stack, 1 Gb/s of network traffic can be processed by a 1-GHz processor. As the technology moves towards 10 Gb/s, 40 Gb/s, and 100 Gb/s network bandwidth, the host processor is likely to no longer be fast enough to keep up with the network traffic. One solution to this problem is to offload the TCP/IP processing to the network interface card (NIC). This solution is known as a TCP/IP offload engine (TOE), reducing the number of host CPU cycles required to achieve wire speed for a 1 Gb/s NIC. For faster NICs, offloading enables the technology to reach wire speed despite the fact that the processing power required to achieve this speed does not yet exist.

         TOE architecture introduces many challenges. One of these challenges is resource management. To implement the TCP/IP stack in hardware, the NIC requires memory for a number of purposes. Examples include space to store the TCP/IP state information, memory for reassembling incoming data, and memory for the TCP send buffer. In comparison to the host system, where memory is cheap and plentiful, memory on a TOE NIC is a scarce resource. The scalability of the solution is in part determined by the amount of memory contained on the NIC. The number of connections that may be offloaded by a NIC depends on the amount of memory that is available.

         One of the largest consumers of the TOE NIC memory is the per-connection TCP send buffer. The send buffer stores data to be sent or data that has been sent but is not yet acknowledged. In conventional TCP/IP implementations, a send buffer is allocated the first time that any data must be sent on a given connection. The send buffer is not released until the connection is closed. The send buffer is often 8K or 16K. A larger send buffe...