Abstract: A method for communication, includes routing unicast data packets among nodes in a network using respective Layer-3 addresses that are uniquely assigned to each of the nodes. Respective Layer-2 unicast addresses are assigned to the nodes in accordance with an algorithmic mapping of the respective Layer-3 addresses. The unicast data packets are forwarded within subnets of the network using the assigned Layer-2 addresses.

Abstract: Communication apparatus includes a memory, which is configured to hold data packets, having respective packet sizes, for transmission over a data link, and a transmitter, which is configured to transmit the data packets over the data link at a bit rate determined by a wire speed of the data link. A shaper is coupled to throttle transmission of the data packets by the transmitter responsively to the respective packet sizes, whereby some of the data packets are transmitted over the data link at a transmission rate that is less than the bit rate.

Abstract: Communication apparatus includes multiple interfaces connected to a packet data network, and a memory coupled to the interfaces and configured as a buffer to contain packets received through ingress interfaces while awaiting transmission to the network via respective egress interfaces. Packet processing logic is configured, upon receipt of a test packet through an ingress interface of the apparatus, to allocate a space in the buffer for storage of a single copy of the test packet, to replicate and transmit sequentially multiple copies of the stored copy of the test packet through a designated egress interface, to receive an indication of a number of copies of the test packet that are to be transmitted, and responsively to the indication, to terminate replication of the test packet and release the allocated space in the buffer.

Abstract: Communication apparatus includes multiple interfaces connected to a packet data network, and a memory coupled to the interfaces and configured as a buffer to contain packets received through ingress interfaces while awaiting transmission to the network via respective egress interfaces. Packet processing logic is configured, upon receipt of a test packet through an ingress interface of the apparatus, to allocate a space in the buffer for storage of a single copy of the test packet, to replicate and transmit sequentially multiple copies of the stored copy of the test packet through a designated egress interface, to receive an indication of a number of copies of the test packet that are to be transmitted, and responsively to the indication, to terminate replication of the test packet and release the allocated space in the buffer.

Abstract: Communication apparatus includes a memory, which is configured to hold data packets, having respective packet sizes, for transmission over a data link, and a transmitter, which is configured to transmit the data packets over the data link at a bit rate determined by a wire speed of the data link. A shaper is coupled to throttle transmission of the data packets by the transmitter responsively to the respective packet sizes, whereby some of the data packets are transmitted over the data link at a transmission rate that is less than the bit rate.

Abstract: A method in a network element includes processing input packets using a set of two or more functions that are defined over parameters of the input packets. Each function in the set produces respective interim actions applied to the input packets and the entire set produces respective end-to-end actions applied to the input packets. An end-to-end mapping, which maps the parameters of at least some of the input packets directly to the corresponding end-to-end actions, is cached in the network element. The end-to-end mapping is queried with the parameters of a new input packet. Upon finding the parameters of the new input packet in the end-to-end mapping, an end-to-end action mapped to the found parameters is applied to the new input packet, without processing the new input packet using the set of functions.

Abstract: A method in a network element that includes multiple interfaces for connecting to a communication network includes receiving via an ingress interface packets that are not allowed to undergo re-routing and that are addressed to a destination via a first egress interface. The packets are forwarded via the first egress interface when there is a valid path from the first egress interface to the destination. When there is no valid path from the first egress interface to the destination, a second egress interface is selected from a group of multiple egress interfaces that have respective paths to the destination and are assigned to packets for which re-routing is allowed, and the packets are forwarded via the second egress interface until recovering a path to the destination.

Abstract: Communication apparatus includes multiple ports for connection to a packet data network. A memory contains, for each port, a respective first, fixed headroom allocation to hold packets received from the network through the port and to contain a shared headroom buffer, which is available to be shared among a plurality of the ports. Flow-control logic allocates to each of the ports, within the shared headroom buffer, a respective second, variable headroom allocation, which varies responsively to fill levels of the respective first headroom allocation and of the shared headroom buffer, thereby defining, for each of the ports, a respective total headroom allocation comprising the respective first and second headroom allocations. The logic is configured to apply flow-control operations in response to the packets received from the network through each port responsively to a total fill level of the respective total headroom allocation of the port.

Abstract: A method for communication, includes routing unicast data packets among nodes in a network using respective Layer-3 addresses that are uniquely assigned to each of the nodes. Respective Layer-2 unicast addresses are assigned to the nodes in accordance with an algorithmic mapping of the respective Layer-3 addresses. The unicast data packets are forwarded within subnets of the network using the assigned Layer-2 addresses.

Abstract: A method for communication, includes routing unicast data packets among nodes in a network using respective Layer-3 addresses that are uniquely assigned to each of the nodes. Respective Layer-2 unicast addresses are assigned to the nodes in accordance with an algorithmic mapping of the respective Layer-3 addresses. The unicast data packets are forwarded within subnets of the network using the assigned Layer-2 addresses.

Abstract: Communication apparatus includes multiple ports for connection to a packet data network. A memory contains, for each port, a respective first, fixed headroom allocation to hold packets received from the network through the port and to contain a shared headroom buffer, which is available to be shared among a plurality of the ports. Flow-control logic allocates to each of the ports, within the shared headroom buffer, a respective second, variable headroom allocation, which varies responsively to fill levels of the respective first headroom allocation and of the shared headroom buffer, thereby defining, for each of the ports, a respective total headroom allocation comprising the respective first and second headroom allocations. The logic is configured to apply flow-control operations in response to the packets received from the network through each port responsively to a total fill level of the respective total headroom allocation of the port.

Abstract: A switching apparatus includes multiple ports, each including a respective buffer, and a switch controller. The switch controller is configured to concatenate the buffers of at least an input port and an output port selected from among the multiple ports for buffering traffic of a long-haul link, which is connected to the input port and whose delay exceeds buffering capacity of the buffer of the input port alone, and to carry out end-to-end flow control for the long haul link between the output port and the input port.

Abstract: A method in a network element that includes multiple interfaces for connecting to a communication network includes receiving via an ingress interface packets that are not allowed to undergo re-routing and that are addressed to a destination via a first egress interface. The packets are forwarded via the first egress interface when there is a valid path from the first egress interface to the destination. When there is no valid path from the first egress interface to the destination, a second egress interface is selected from a group of multiple egress interfaces that have respective paths to the destination and are assigned to packets for which re-routing is allowed, and the packets are forwarded via the second egress interface until recovering a path to the destination.

Abstract: A switching apparatus includes multiple ports, each including a respective buffer, and a switch controller. The switch controller is configured to concatenate the buffers of at least an input port and an output port selected from among the multiple ports for buffering traffic of a long-haul link, which is connected to the input port and whose delay exceeds buffering capacity of the buffer of the input port alone, and to carry out end-to-end flow control for the long haul link between the output port and the input port.

Abstract: A method in a network element includes processing input packets using a set of two or more functions that are defined over parameters of the input packets. Each function in the set produces respective interim actions applied to the input packets and the entire set produces respective end-to-end actions applied to the input packets. An end-to-end mapping, which maps the parameters of at least some of the input packets directly to the corresponding end-to-end actions, is cached in the network element. The end-to-end mapping is queried with the parameters of a new input packet. Upon finding the parameters of the new input packet in the end-to-end mapping, an end-to-end action mapped to the found parameters is applied to the new input packet, without processing the new input packet using the set of functions.

Abstract: A method in a communication network includes defining a root congestion condition for a network switch if the switch creates congestion in the network while switches downstream are congestion free, and a victim congestion condition if the switch creates the congestion as a result of one or more other congested switches downstream. A buffer fill level in a first switch, created by network traffic, is monitored. A binary notification is received from a second switch, which is connected to the first switch. A decision whether the first switch or the second switch is in a root or a victim congestion condition is made, based on both the buffer fill level and the binary notification. A network congestion control procedure is applied based on the decided congestion condition.

Abstract: A method for communication, includes routing unicast data packets among nodes in a network using respective Layer-3 addresses that are uniquely assigned to each of the nodes. Respective Layer-2 unicast addresses are assigned to the nodes in accordance with an algorithmic mapping of the respective Layer-3 addresses. The unicast data packets are forwarded within subnets of the network using the assigned Layer-2 addresses.

Abstract: A method for data storage includes mapping a queue pair (QP) of a channel adapter to a specified Fiber Channel (FC) exchange for communication with a storage device. Upon receiving at the channel adapter from a host computer a storage command directed to the storage device, the storage command is executed by transmitting data packets over a switched network from the channel adapter to the storage device using the specified exchange and performing a remote direct memory access (RDMA) operation on the channel adapter using the mapped QP.

Abstract: Communication apparatus includes a switch, which includes switching logic, multiple ports for connection to a network, and a management port, and which is configured to assign both a first link-layer address and a second link-layer address to the management port. A host processor includes a memory and a central processing unit (CPU), which is configured to run software implementing a management agent for managing functions of the switch. A network interface controller (NIC) is connected to the management port and is configured to convey incoming management packets, which are directed by the switch to the first link-layer address, to the CPU for processing by the management agent, and to write directly to the memory data contained in incoming remote direct memory access (RDMA) packets, which are directed by the switch to the second link-layer address.

Abstract: A method for communication includes sending a pause frame from a first node to a second node over a communication link between the nodes. In response to the pause frame, one or more data frames are immediately transmitted from the second node to the first node upon receipt of the pause frame at the second node.