Methods and apparatus for caching information associated with packets are disclosed. According to one aspect of the present invention, a system for processing a packet includes a controller with a processor and a controller data cache, a bus, a memory interface, and a separate data cache. The memory interface may be accessed by the controller via the bus, and is arranged to be in communication with a substantially external memory. The separate data cache, which is also in communication with the …

Systems and methods for controlling power of WDM channels in a WDM receiver. A preamplifier is provided prior to a demultiplexer in the WDM receiver chain. The gain of the preamplifier may be controlled based on power measurements made on individual WDM channels. A filter with controllable tilt may be employed to compensate for amplifier gain tilt and assure that all of the WDM channels remain within the dynamic range of the photodetector and receiver electronics. This provides improved bit erro…

Methods and apparatus for substantially minimizing single points of failure for circuit paths in networks with mixed protection schemes are disclosed. According to one aspect of the present invention, a method for routing circuit paths between a source and a destination of a network includes identifying a first available circuit path between the source and the destination. The first available circuit path includes a first plurality of links which each have an associated protection type. The meth…

A method and system for automatically interconnecting IPv4 networks across an IPv6 network are disclosed. The method includes receiving an IPv4 packet at an ingress router in the IPv6 network and finding the longest match IPv4 routing entry for IPv4 addresses in the received packet to identify an egress router in the IPv6 network. The IPv4 packet is encapsulated to create an IPv6 packet, wherein destination and source addresses of the encapsulated packet identify a subnet router anycast correspo…

Methods and systems for identifying instability or a loop in a network. In one method, a first BPDU message is received at a switch indicating a topology change. The message includes a bridge identifier identifying a network device originating the first BPDU message. A second BPDU is generated at the switch and includes the bridge identifier identifying the network device originating the first BPDU message. The method further includes transmitting the second BPDU message indicating the topology …

A method and system for conveying management information across a network are disclosed. The method includes generating an Ethernet packet comprising a converged data link header in place of an Ethernet preamble and transmitting the modified packet from a network element. The header is configured to provide support for network management.

A method and system for performing route calculations in a link state routing protocol at a node within a computer network. The method includes evaluating existing routes of the node when new route information is received and recalculating routes for the node only when the new route information improves at least one of the existing routes or at least one of the existing routes is made worse or lost.

Systems and methods for replacing software controlling active routers while minimizing impact on network operation are provided by virtue of one embodiment of the present invention. The software replacement process takes advantage of packet processor redundancy. An active packet switching device to be reprogrammed is de-activated and a redundant packet switching device takes over. The no longer active packet switching device is reprogrammed before being reactivated.

In one embodiment, a method for tracing a connection path from a source node to a destination node through a network having one or more transparent proxies includes generating a trace packet at the source node, transmitting the trace packet over the network towards the destination node, and receiving trace response packets in response to transmission of the trace packet. The trace response packets include a packet from the destination node and a packet from each of the transparent proxies in a d…

Systems and methods for implementing per-session load balancing of packets that increase traffic sharing and reduce systematic unequal distribution of traffic are provided by virtue of one embodiment of the present invention. A method for operating a selected router is provided that uses a load balancing algorithm that is configured to de-correlate distribution of sessions among the active paths at the selected router relative to distributions of sessions of other algorithms at other routers of …