Network adapter with large frame transfer emulation

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments disclosed below were selected by way of illustration and not by way of limitation.
The terms network adapter and network interface card (NIC) are used somewhat interchangeably herein, with the realization that a network adapter need not be implemented on a "card", but may, e.
g.
, be implemented directly on a motherboard or in an embedded network appliance.
Also, a network adapter typically comprises both a hardware component and a software driver running on the host system.
As used herein, a "context" or "connection context" refers to the group of variables (addresses, data pointers, etc.
) used to describe a packet segmentation (transmit) or reassembly (receive) job performed by the network adapter according to an embodiment of the invention.
Although a context for each of several TCP/IP connections may be open simultaneously, normally only one context for any one connection will be active at any given time.
Briefly and by way of introduction, overcoming the identified limitations of TCP segmentation offload--its limitation to a single operating system, data sizes no greater than the receive window size, and transmit-only capability--has motivated the development of the disclosed embodiments.
The disclosed embodiments can overcome either the first only, the first and second, or all three of these limitations, and can implement other enhancements that potentially increase the performance of a system by further decreasing both the number of communications between host and interface card and the number of operations that must be performed by the host.
In general, the disclosed embodiments can be made operating system independent.
The network adapter indicates to its host an ability to transfer large data blocks (e.
g.
, six times or ten times the standard Ethernet block size for an Ethernet adapter), even when (a) it is not or cannot be physically configured to actually transfer such a data block in a single physical frame, and/or (b) the remote endpoint with which it is communicating cannot accept such a data block