摘要:
A high speed communications interface divides data into a plurality of lanes, each lane encoded with clocking information, serialized, and sent to an interface. During cycles when there is no available data to send, IDLE_EVEN and IDLE_ODD cells are sent on alternating cycles. Data is transmitted by sending a header which spans all lanes and includes a START symbol. The final data transaction includes a Frame Check Sequence (FCS) which operates over the entire header and data. The packet is terminated by an END symbol, which is sent after the final data, and the remainder of the lanes are padded with IDLE_EVEN, IDLE_ODD, IDLE_EVEN_BUSY, or IDLE_ODD_BUSY cycles. The interface has a variable clock rate.
摘要:
A high speed communications interface divides data into a plurality of lanes, each lane encoded with clocking information, serialized, and sent to an interface. During cycles when there is no available data to send, IDLE_EVEN and IDLE_ODD cells are sent on alternating cycles. Data is transmitted by sending a header which spans all lanes and includes a START symbol. The final data transaction includes a Frame Check Sequence (FCS) which operates over the entire header and data. The packet is terminated by an END symbol, which is sent after the final data, and the remainder of the lanes are padded with IDLE_EVEN, IDLE_ODD, IDLE_EVEN_BUSY, or IDLE_ODD_BUSY cycles. The interface has a variable clock rate.
摘要:
Disclosed are apparatus and methods for facilitating communication between two devices from two different VSANs by propagating each device's presence from a first VSAN to the other device's different VSAN using a network address translation (NAT) mechanism. For instance, a first device, such as a host H1, from VSAN_A is allowed to access data from a second device, such as disk D1, of VSAN_B by propagating D1's presence into VSAN_A and H1's presence into VSAN_B. This awareness is accomplished by propagating an identifier for each device into the edge VSAN of the other device, as well as into any transit VSAN. So as to not duplicate identifiers in any one of the VSANs, a device's presence is propagated into a particular VSAN by assigning an unused domain for use by such device in the particular VSAN.
摘要:
In one embodiment, a first packet is forwarded based on a network layer routing decision rendered by a router. A shortcut entry is generated based on a first header of the first packet. The shortcut entry is stored. In response to the shortcut entry, and absent a network layer routing decision rendered by a router, subsequent packets having a subsequent header are forwarded if the subsequent header has at least one field which matches a field of the first header. Such technique may be implemented by a switch coupled to the router.
摘要:
A technique is provided for implementing online restriping of a volume in a storage area network. A first instance of the volume is instantiated at a first port of the fibre channel fabric for enabling I/O operations to be performed at the volume. While restriping operations are being performed at the volume, the first port is able to concurrently perform I/O operations at the volume.
摘要:
A network traffic shaper provides high-speed, multi-level shaping. The traffic shaper is in communicating relationship with a forwarding engine, and includes a queue controller having a plurality of queues for storing messages, a scheduler for computing release times, at least one time-searchable memory and a corresponding memory controller. Each queue is preferably associated with a corresponding traffic specifier, and a release time is computed for each queue and stored in the time-searchable memory. When a stored release time expires, the message at the head of the corresponding queue is retrieved and is either moved into a different queue or forwarded by the network device. By moving messages through two or more queues, each having its own release time computed in response to a different traffic specifier, the traffic shaper can perform multi-level shaping on network messages.
摘要:
A technique enables learning and switching of frames between line cards that are interconnected by a switch fabric of a distributed network switch. The network switch comprises a router and a plurality of forwarding engines, each having an associated forwarding table. The distributed learning and switching technique configures (i) the router to issue an extra copy of a routed frame to an ingress card having a port attached to the source of the frame; (ii) the router to ensure that the contents of a source index field of the routed frame header indicate that the frame originated from the ingress card; (iii) the router to assert a shortcut bit in the header of the routed frame; (iv) a forwarding engine on an egress card having a port attached to the destination of the frame to generate and issue a media access control notification frame to the ingress card and (v) a forwarding engine on the ingress card to mark an established entry in a layer 2 (L2) portion of its forwarding table as ineligible for normal L2 aging policies.
摘要:
A shortcut technique implements forwarding decision shortcuts at a switch for frames routed between subnetworks of a computer network. The switch monitors the flow of a first frame of a particular type to and from the router, which renders a forwarding decision for routing the frame. The switch records information stored in network layer header of a packet encapsulated within the first frame, and then compares that information with the information stored in network layer headers of packets contained within subsequent frames of that particular type. Forwarding decisions for these subsequent frames are then rendered by hardware logic circuits of the switch rather than by the router.
摘要:
A method and apparatus for implementing Quality of Service (QoS) policy in a data communications network. An active flow content addressable memory (CAM) contains entries of flow information for each active flow of packets passing through a given node of the data communications network. The CAM has associated with each entry a packet counter, a byte counter, a token bucket, and a contract value. Each flow is assigned one of a plurality of output queues and optionally at least one output threshold value. A token bucket algorithm is employed on each flow to determine whether packets from that flow exceed the contract value. Such packets may be dropped or optimally modified to reflect an alternate output queue and/or alternate threshold before being sent to the selected output queue for transmission from the node.
摘要:
The invention replicates a packet requiring high availability and transmits it from two or more ports of a switch, for example a wiring closet Layer 2 switch. The parent packet carries a unique sequence number. The copies of the packet each carry the parent packet's unique sequence number. Each copy of the packet then travels on separate pathways through routers (Layer 3 network devices). The pathways are maintained separate by assigning high costs in a LSP routing sense to links connecting the two paths, and by assigning low costs to links along the desired paths. The two identical packets converge on the destination station. The destination station accepts the first packet with a particular sequence number, and discards any later packets with the same sequence number. In the event that a link in one path has a catastrophic failure, then the packet travelling along the other path reaches the destination station and service remains operative without interruption. The lost path is then recomputed by the a router (if any) still receiving the lost packet. A new non-converging path may be selected if any are available, depending upon the topology. After the disruption is repaired, the original dual pathways may once again be established.