US 6,996,070 B2 · TCP/IP offload device with reduced sequential processing

Abstract

A TCP Offload Engine (TOE) device includes a state machine that performs TCP/IP protocol processing operations in parallel. In a first aspect, the state machine includes a first memory, a second memory, and combinatorial logic. The first memory stores and simultaneously outputs multiple TCP state variables. The second memory stores and simultaneously outputs multiple header values. In contrast to a sequential processor technique, the combinatorial logic generates a flush detect signal from the TCP state variables and header values without performing sequential processor instructions or sequential memory accesses. In a second aspect, a TOE includes a state machine that performs an update of multiple TCP state variables in a TCB buffer all simultaneously, thereby avoiding multiple sequential writes to the TCB buffer memory. In a third aspect, a TOE involves a state machine that sets up a DMA move in a single state machine clock cycle.

Claims23

Dependent claims

A TCP offload engine (TOE) capable of offloading, from a host, TCP protocol processing tasks that are associated with a TCP connection, the TOE comprising:

a first memory that stores and simultaneously outputs at least two TCP state values associated with the TCP connection, wherein the at least two TCP state values are taken from the group consisting of:
a receive packet sequence limit, an expected receive packet sequence number, a transmit sequence limit, a transmit acknowledge number, and a transmit sequence number;
a second memory that stores and simultaneously outputs at least two packet header values of a packet communicated over the TCP connection, wherein the at least two packet header values are taken from the group consisting of:
a receive packet sequence number, a packet payload size, a packet acknowledge number, and a packet transmit window value;
and
combinatorial logic that receives said at least two TCP state values and said at least two packet header values and generates therefrom a flush detect signal indicative of whether an error condition has occurred, the two TCP state values and the two packet header values all being supplied to the combinatorial logic simultaneously.

3 more elements

A TCP offload engine (TOE) capable of offloading, from a host, TCP protocol processing tasks that are associated with a TCP connection, the TOE comprising:

a first memory that stores and simultaneously outputs at least two TCP state values associated with the TCP connection, wherein the at least two TCP state values are taken from the group consisting of:
a receive packet sequence limit, an expected receive packet sequence number, a transmit sequence limit, a transmit acknowledge number, and a transmit sequence number;
a second memory that stores and simultaneously outputs at least two packet header values of a packet communicated over the TCP connection, wherein the at least two packet header values are taken from the group consisting of:
a receive packet sequence number, a packet payload size, a packet acknowledge number, and a packet transmit window value;
and
combinatorial logic that receives said at least two TCP state values and said at least two packet header values and generates therefrom a flush detect signal indicative of whether an error condition has occurred, the two TCP state values and the two packet header values all being supplied to the combinatorial logic simultaneously, wherein the TOE transfers the receive packet sequence limit, the expected receive packet sequence number, the transmit sequence limit, the transmit acknowledge number, and the transmit sequence number to the host if the flush detect signal is indicative of the error condition.

3 more elements

A TCP offload engine (TOE) capable of offloading, from a host, TCP protocol processing tasks that are associated with a TCP connection, the TOE comprising:

a first memory that stores and simultaneously outputs at least two TCP state values associated with the TCP connection, wherein the at least two TCP state values are taken from the group consisting of:
a receive packet sequence limit, an expected receive packet sequence number, a transmit sequence limit, a transmit acknowledge number, and a transmit sequence number;
a second memory that stores and simultaneously outputs at least two packet header values of a packet communicated over the TCP connection, wherein the at least two packet header values are taken from the group consisting of:
a receive packet sequence number, a packet payload size, a packet acknowledge number, and a packet transmit window value;
and
combinatorial logic that receives said at least two TCP state values and said at least two packet header values and generates therefrom a flush detect signal indicative of whether an error condition has occurred, the two TCP state values and the two packet header values all being supplied to the combinatorial logic simultaneously, wherein the TOE can control a plurality of TCP connections, each of said TCP connections being associated with a TCB identifier, and wherein the first memory comprises a plurality of transaction control blocks (TCB), wherein the first memory can be addressed by a TCB identifier to access a TCB that contains TCP state information for a TCP connection associated with the TCB identifier.

3 more elements

A TCP offload engine (TOE) capable of offloading, from a host, TCP protocol processing tasks that are associated with a TCP connection, the TOE comprising:

a first memory that stores and simultaneously outputs at least two TCP state values associated with the TCP connection, wherein the at least two TCP state values are taken from the group consisting of:
a receive packet sequence limit, an expected receive packet sequence number, a transmit sequence limit, a transmit acknowledge number, and a transmit sequence number;
a second memory that stores and simultaneously outputs at least two packet header values of a packet communicated over the TCP connection, wherein the at least two packet header values are taken from the group consisting of:
a receive racket sequence number, a packet payload size, a packet acknowledge number, and a packet transmit window value;
and
combinatorial logic that receives said at least two TCP state values and said at least two packet header values and generates therefrom a flush detect signal indicative of whether an error condition has occurred, the two TCP state values and the two packet header values all being supplied to the combinatorial logic simultaneously, wherein the combinatorial logic is part of a state machine, the state machine being clocked by a clock signal, wherein the combinatorial logic generates said flush detect signal from said at least two TCP state values and said at least two packet header values within approximately one period of the clock signal, wherein the state machine does not fetch instructions, decode the instructions, and execute the instructions, and
wherein a packet having a payload is received onto the TOE, the TOE further comprising:
a DMA controller that moves the payload from the TOE to the host using a source address value, a size value indicating an amount of information to move, and a destination address value, wherein the state machine causes the source address value, the size value, and the destination address value to be supplied to the DMA controller in a single state of the state machine.

5 more elements

A TCP offload engine (TOE) capable of offloading TCP protocol processing tasks from a host, the TCP protocol processing tasks being associated with a TCP connection, the TOE comprising:

a first memory that stores and simultaneously outputs at least two TCP state values associated with the TCP connection, wherein the at least two TCP state values are taken from the group consisting of:
a receive packet sequence limit, an expected receive packet sequence number, a transmit sequence limit, a transmit acknowledge number, and a transmit sequence number;
a second memory that stores and simultaneously outputs at least two packet header values of a packet communicated over the TCP connection, wherein the at least two packet header values are taken from the group consisting of:
a receive packet sequence number, a packet payload size, a packet acknowledge number, and a packet transmit window value;
and
a hardware state machine that receives said at least two TCP state values and said at least two packet header values and generates therefrom a signal indicative of whether an exception condition has occurred, the two TCP state values and the two packet header values all being supplied to the hardware state machine simultaneously, wherein the hardware state machine is clocked by a clock signal, wherein the hardware state machine generates said signal from said at least two TCP state values and said at least two packet header values within approximately one period of the clock signal, wherein the hardware state machine causes the expected packet receive sequence number and the receive packet sequence limit values in the first memory to be updated in a single period of the clock signal.

3 more elements

A TCP offload engine (TOE) capable of offloading TCP protocol processing tasks from a host, the TCP protocol processing tasks being associated with a TCP connection, the TOE comprising:

a first memory that stores and simultaneously outputs at least two TCP state values associated with the TCP connection, wherein the at least two TCP state values are taken from the group consisting of:
a receive packet sequence limit, an expected receive packet sequence number, a transmit sequence limit, a transmit acknowledge number, and a transmit sequence number;
a second memory that stores and simultaneously outputs at least two packet header values of a packet communicated over the TCP connection, wherein the at least two packet header values are taken from the group consisting of:
a receive packet sequence number, a packet payload size, a packet acknowledge number, and a packet transmit window value;
and
a hardware state machine that receives said at least two TCP state values and said at least two packet header values and generates therefrom a signal indicative of whether an exception condition has occurred, the two TCP state values and the two packet header values all being supplied to the hardware state machine simultaneously, wherein the hardware state machine is clocked by a clock signal, wherein the hardware state machine generates said signal from said at least two TCP state values and said at least two packet header values within approximately one period of the clock signal, wherein the first memory is a dual-port memory that has a first interface and a second interface, the hardware state machine reading from and writing to the first memory via the first interface, and wherein information passes from the host and into the first memory via the second interface.

3 more elements

A TCP offload engine (TOE) capable of performing TCP protocol processing tasks, the TCP protocol processing tasks being associated with a TCP connection, the TOE comprising:

a first memory that stores and simultaneously outputs at least two TCP state values associated with the TCP connection, wherein the at least two TCP state values are taken from the group consisting of:
a receive packet sequence limit, an expected receive packet sequence number, a transmit sequence limit, a transmit acknowledge number, and a transmit sequence number;
a second memory that stores and simultaneously outputs at least two packet header values of a packet communicated over the TCP connection, wherein the at least two packet header values are taken from the group consisting of:
a receive packet sequence number, a packet payload size, a packet acknowledge number, and a packet transmit window value;
and
a state machine that includes an amount of combinatorial logic, wherein the combinatorial logic receives said at least two TCP state values and said at least two packet header values and generates therefrom a signal indicative of whether an exception condition has occurred, the two TCP state values and the two packet header values all being supplied to the combinatorial logic simultaneously, and wherein the state machine causes the expected packet receive sequence number value and the receive packet sequence limit value in the first memory to be updated simultaneously.

3 more elements

Dependencies are inferred from the claim text.

TCP/IP offload device with reduced sequential processing

Life of this patent

TCP/IP offload device with reduced sequential processing

Life of this patent

Abstract

Claims23