Abstract: Data is protected using locks, with the protected data sometimes being included in the locking messages, which may reduce overall processing latency, and/or reduce a bandwidth requirement for and/or number of storage operations accessing the native storage of the protected data. For example, the lock manager receives lock requests from each of the requesters, and selectively grants the lock requests. The protected data is typically communicated in the locking messages when the lock is highly contested, or at least two request for access to the data are pending. The lock manager initiates the sequence by indicating in a grant message to a requester to include the protected data in its release message. The lock manager then copies this data received in the release message to its grant message to the next requestor.

Abstract: Rate computations are performed such as for use in scheduling activities, such as, but not limited to packets, processes, traffic flow, etc. One implementation identifies an approximated inverse rate, a fix-up adjustment value, and a quantum. An activity measurement value is maintained based on a measure of activity, and a rate control value is maintained based on the measure of activity and the approximated inverse rate. The fix-up adjustment value is applied once each quantum to the rate control value to maintain rate accuracy of the activity. In one implementation, the control value is a scheduling value used for determining when to perform a next part of the activity (e.g., send one or more packets). Scheduling rates are efficiently and compactly stored in an inverse form, which may have advantages in terms of rate granularity, accuracy, and the ability to deliver service smoothly.

Abstract: Methods and devices are provided for the efficient allocation and deletion of virtual output queues. According to some implementations, incoming packets are classified according to a queue in which the packet (or classification information for the packet) will be stored, e.g., according to a “Q” value. For example, a Q value may be a Q number defined as {Egress port number?Priority number?Ingress port number}. Only a single physical queue is allocated for each classification. When a physical queue is empty, the physical queue is preferably de-allocated and added to a “free list” of available physical queues. Accordingly, the total number of allocated physical queues preferably does not exceed the total number of classified packets. Because the input buffering requirements of Fibre Channel (“FC”) and other protocols place limitations on the number of incoming packets, the dynamic allocation methods of the present invention result in a sparse allocation of physical queues.

Abstract: The invention provides a method and system for coupling a SONET/SDH network to a routing network that does not have a single point of failure. Multiple routers are coupled between the SONET/SDH network and the routing network, one for each data path; for example, a first router for the working data path and a second router for the protection data path. The routers intercommunicate to force APS to switch data paths bidirectionally, so as to allow only a single router for each data path.

Abstract: Disclosed are various ways of performing reliable multicast communication which may include, for example, designating which node or nodes to acknowledge a message and/or whether to immediately acknowledge or delay acknowledgement of a message, which may be of particular use with routers, packet switching systems, computer systems, and other devices. Multiple nodes are typically sent a multicast message, which includes an indication of one or more designated nodes to acknowledge the message, a sequence number or other message identification value, and possibly an indication whether an immediate or delayed acknowledgment is requested. A node receiving the message responds accordingly if it is designated to acknowledge the message, which may include requesting any missing messages, and/or sending an acknowledgment message for the messages it has received since it sent its last acknowledgment message.

Abstract: Sequences of items may be maintained using ordered locks. These items may correspond to anything, but using ordered locks to maintain sequences of packets may be particularly useful. One implementation uses a locking request, acceptance, and release protocol. One implementation associates instructions with locking requests such that when a lock is acquired, the locking mechanism executes or causes to be executed the associated instructions as an acceptance request of the lock is implied by the association of instructions (or may be explicitly requested). In some applications, the ordering of the entire sequence of packets is not required to be preserved, but rather only among certain sub-sequences of the entire sequence of items, which can be accomplished by converting an initial root ordered lock (maintaining the sequence of the entire stream of items) to various other locks (each maintaining a sequence of different sub-streams of items).

Abstract: Methods and apparatus for providing tandem connection monitoring and performance monitoring capabilities in Ethernet and converged data link protocols are disclosed. According to one aspect of the present invention, a method for processing a packet which includes a preamble arrangement having at least one associated frame involves receiving a packet from a first network element included in a network path at a second network element included in the network path, and determining whether at least one error has arisen between a source of the network path and the second network element. When it is determined that an error has arisen between the source of the network path and the second network element, a first error count indication is inserted in the preamble arrangement to substantially account for the error.

Abstract: Reverse path forwarding protection of packets is provided using automated population of access control lists based on a forwarding information base. One implementation identifies a lookup value by extracting one or more values including a source address from a packet. An access control list lookup operation is performed on an access control list based on the lookup value to identify a permit or a deny condition, the access control list including multiple access control list entries. The packet is processed based on the permit or the deny condition identified in by the access control list lookup operation, this processing the packet based on the permit condition includes performing a forwarding lookup operation on a representation of a forwarding information base to identify a location and forwarding the packet to the location. The access control list entries are automatically generated based on a forwarding information base.

Abstract: Methods and apparatus for enabling a protected circuit path to be created efficiently are disclosed. In accordance with one embodiment of the present invention, a method for creating a protected circuit path within an optical network system includes identifying a first node, a second node, and a third node. Once the nodes are identified, a pseudo link or a virtual link may be created between the second node and the third node. A first circuit path is then routed between the first node and the second node, and a second circuit path which protects that first circuit path is routed between the first node and the third node using the pseudo link.

Abstract: A telephone is provided for delivering content to a client that is coupled to a communications network. The telephone includes a processor and a network interface operable to couple the telephone to the communications network. The telephone also includes a handset operable to provide oral communication by a user of the telephone using the network interface. Furthermore, the telephone includes a memory that is coupled to the processor and operable to store content for delivery to the client using the network interface. The content that is stored is associated with the operation of the telephone. In a particular embodiment, the client to which the content is delivered is a Web browser, and the content is at least one HyperText Markup Language document to be displayed in the Web browser.

Abstract: Comparison tree data structures of particular use in performing lookup operations are disclosed. A data structure typically includes first and second elements of a subtree, the subtree including a root node. The first and the second elements each include: a node value field for indicating one or more paths from the root node through the subtree for reaching the respective first or second element. The first node also includes a next node indication for use in traversing to the second element. Additionally, one embodiment identifies a lookup value, wherein lookup value includes a first lookup path and a next portion of the lookup value. A first node including a first node value is identified, with the first node value. The first node value is compared with the first lookup path to identify that a matching child node has been identified.

Abstract: Improved systems and methods for implementing data-driven protocols are provided. In one embodiment, improved implementations of multicast routing protocols are provided. Separation between multicast forwarding and control elements are provided by use of a powerful yet simple application program interface (API) for inter-module communication. The API is multicast-routing-protocol-independent and can be used to express the forwarding state of any existing multicast protocol. Efficient platform-specific implementations are facilitated.

Abstract: A method and system for pre-empting a low-priority traffic with high-priority traffic over a serial link utilizes special codes to delimit a high-priority message embedded within a low-priority message.

Abstract: An auto-determination technique detects whether a DTE or DCE is connected to an RS232 port. The port is then automatically configured to interface with the connected equipment.

Abstract: A method is provided for blocking attacks on a private network (12). The method is implemented by a routing device (10) interconnecting the private network (12) to a public network (14). The method includes analyzing an incoming data packet from the public network (14). The incoming data packet is then matched against known patterns where the known patterns are associated with known forms of attack on the private network (12). A source of the data packet is then identified as malicious or non-malicious based upon the matching. In one embodiment, one of the known forms of attack is a denial of service attack and an associated known pattern is unacknowledged data packets. In another embodiment, one of the known forms of attack is an address spoofing attack and an associated known pattern is a data packet having a source address matching an internal address of the private network (12).

Abstract: Methods, apparatus, and other mechanisms are disclosed for generating accounting or other data based on that indicated in access control lists or other specifications, and typically using associative memory entries in one or more associative memory banks and/or memory devices. One implementation identifies an access control list including multiple access control list entries, with a subset of these access control list entries identifying accounting requests. Accounting mechanisms are associated with each of said access control list entries in the subset of access control list entries identifying accounting requests. An item is identified, and a corresponding accounting mechanism is updated. In one implementation, the item includes at least one autonomous system number. In one implementation, at least one of the accounting mechanisms is associated with at least two different access control list entries in the subset of access control list entries identifying accounting requests.

Abstract: Methods, apparatus, and other mechanisms are disclosed for merging lookup results, such as from one or more associative memory banks and/or memory devices. An access list is identified. A first set of entries corresponding to a first feature of the access control list entries and a second set of entries corresponding to a second feature of the access control list entries are identified. First and second associative memory banks are programmed respectively based on the first and second sets of entries. Lookup operations are then typically performed substantially simultaneously on the first and second sets of associative memory entries programmed in the associative memory banks to generate multiple lookup results, with these results typically being identified directly, or via a lookup operation in an adjunct memory or other storage mechanism. These lookup results are then combined to generate a merged lookup result.

Abstract: Methods and apparatus are disclosed for defining and using associative memory entries with force no-hit and priority indications of particular use in implementing policy maps in communication devices. In one use, a set of entries is determined based on a policy map with a force no-hit indication being associated with one or more of the entries. Additionally, programmable priority indications may be associated with one or more of the entries, or with the associative memory devices, associative memory banks, etc. The force no-hit indications are often used in response to identified deny instructions in an access control list or other policy map. A lookup operation is then performed on these associative memory entries, with highest matching result or results identified based on the programmed and/or implicit priority level associated with the entries, or with the associative memory devices, associative memory banks, etc.

Abstract: An apparatus and method for enabling Cisco legacy power to support IEEE 802.3 AF standard power. A network power system capable of delivering data terminal equipment power via a media dependent interface includes power source equipment according to Cisco legacy power and at least one powered device according to IEEE standard power. A power compatibility module is inserted between the power source equipment and the powered device to enable the power source equipment to appear according to IEEE standard power and the powered device to appear according to Cisco legacy power. The module includes switches, a DC/DC converter, an IEEE power source equipment circuit, and an isolator. The module optionally includes a user signaling device for communicating operating conditions of the module to a user. The module may be connected to two ports of the power source equipment to supply adequate power levels to the powered device.

Abstract: A host object representing a user, a service object representing a service, and a connection object linking the two may be utilized in order to provide Quality of Service (QoS). The host object and/or connection object may contain a provisioning scheme defining a limit on traffic, which can be provided through either a local or remote programming mechanism. When traffic flows through the host object and/or connection object, the appropriate provisioning scheme is utilized to determine which packets to discard.