Abstract: A method and apparatus are provided for creating a virtual hierarchical local area network. The method and apparatus provide a hierarchical framing technique that allows a network architecture to realize a local area network hierarchy within the network. In this manner, a first local area network hierarchy is defined by communication in a first frame format between a first set of network devices and a second set of network devices. A second local area network hierarchy is defined by communication in a second frame format between members of the second set of network devices. The second frame format includes the fields of a frame in the first frame format that is used to communicate between the first set of communication devices and the second set of communication devices.

Abstract: A method and apparatus are provided for creating a virtual hierarchical local area network. The method and apparatus provide a hierarchical framing technique that allows a network architecture to realize a local area network hierarchy within the network. In this manner, a first local area network hierarchy is defined by communication in a first frame format between a first set of network devices and a second set of network devices. A second local area network hierarchy is defined by communication in a second frame format between members of the second set of network devices. The second frame format includes the fields of a frame in the first frame format that is used to communicate between the first set of communication devices and the second set of communication devices.

Abstract: A method and apparatus are provided for creating a virtual hierarchical local area network. The method and apparatus provide a hierarchical framing technique that allows a network architecture to realize a local area network hierarchy within the network. In this manner, a first local area network hierarchy is defined by communication in a first frame format between a first set of network devices and a second set of network devices. A second local area network hierarchy is defined by communication in a second frame format between members of the second set of network devices. The second frame format includes the fields of a frame in the first frame format that is used to communicate between the first set of communication devices and the second set of communication devices.

Abstract: Capability based addressing in a communication network enables protocol data units (PDUs) to be addressed to network constructs such as network elements or interfaces with particular capabilities rather than with specific addresses. This allows PDUs to be addressed to network constructs without first identifying the network constructs or even knowing of the existence of the construct. By broadcasting a capability based PDU onto a network it is therefore possible to communicate with a particular type of device rather than with a particular identified device. This is applicable, for example, in connection with loop and backdoor detection. By broadcasting a PDU onto a network, e.g. using a hello-response protocol, it is possible to identify network constructs that should not be present on the network if the communication network is configured properly. An alarm or corrective action may be taken upon detection of a response.

Abstract: A P device interworks CE devices connected to the P device using different types of data links. The P device learns the address of a local CE device by monitoring the control messages, such as address resolution messages, originating from the local device. The P device may share the address of a local CE device with another local CE device by initiating a control message or responding to a control message issued by one of the local CE devices. This latter mechanism in effect hides the heterogeneous nature of the network.

Abstract: Capability based addressing in a communication network enables protocol data units (PDUs) to be addressed to network constructs such as network elements or interfaces with particular capabilities rather than with specific addresses. This allows PDUs to be addressed to network constructs without first identifying the network constructs or even knowing of the existence of the construct. By broadcasting a capability based PDU onto a network it is therefore possible to communicate with a particular type of device rather than with a particular identified device. This is applicable, for example, in connection with loop and backdoor detection. By broadcasting a PDU onto a network, e.g. using a hello-response protocol, it is possible to identify network constructs that should not be present on the network if the communication network is configured properly. An alarm or corrective action may be taken upon detection of a response.

Abstract: Ethernet OAM domains may be defined by defining reference points on the Ethernet network and using the reference points to insert and extract Ethernet OAM flows. The reference points may be network elements at the edge of a provider's domain, customer elements, or network elements configured to perform OAM flow handoffs between domains. By defining OAM multicast addresses and OAM flow identifiers, and allowing the reference points to be addressed by the multicast address and filtering to be performed by the reference points based on the OAM flow identifiers, OAM flows may be defined on the network. For example, customer-customer OAM flows may be defined, intra-provider and inter-provider OAM flows may be defined, and various segment OAM flows may be defined. An OAM frame format is provided to enable the OAM flows to be carried in a conventional Ethernet network.

Abstract: Ethernet OAM may be used to trace a path on an Ethernet network. If the path reaches the destination, there is no fault. If the path doesn't reach the destination, the network element farthest along the path is adjacent the fault. The path trace may be used from both ends of a given path to confirm the presence of a single fault or to determine the likelihood of multiple faults on the path. A path trace Ethernet OAM frame may be issued on the network with instructions that network elements with knowledge of a destination address should respond. If a network element knows the destination address, the receiving network element responds to the initiating network element with a unicast OAM frame and forwards the OAM frame if possible. The sequence of unicast response frames allows the initiating network element to build a path through the network toward the destination element and identify where the path stops.

Abstract: Ethernet OAM connectivity check may be used to detect connectivity failures across a given pair of network elements on an Ethernet network. Connectivity check frames are generated and sent to a specific unicast DA or to a multicast DA. Once a network element begins to receive connectivity check frames, it expects to continue to receive further periodic connectivity check frames from that network element. If the network element stops receiving periodic connectivity check frames, it detects that connectivity to the sending network element is broken. Once a fault is identified, the fault may be verified using a loopback function, which causes a network element receiving an Ethernet frame to transmit a corresponding frame back to the original network element. Loopback may be intrusive such that all received frames are looped back except OAM frames, or non-intrusive where only OAM frames are looped back.

Abstract: Network topography may be discovered by a network element on an Ethernet network by collecting connectivity check messages periodically issued by other network elements on the network and using the information gleaned from those messages to build a topography database. Since the connectivity check messages may be link level or service instance based, the topography database may include network topography as well as service topography on the Ethernet network. Ethernet OAM loopback frames may also be used to cause network elements on the Ethernet network to issue response frames directed to the initiating network element. By collecting responses from the responding network elements, the initiating network element can build a topography database of network elements on the Ethernet network. This topography database may show the overall network topography or service instances on the network, and may provide visibility within one or more domains.

Abstract: Packets in a Per Hop Basis (PHB) are metered by a network element to see if they fall within a Committed Information Rate (CIR) or Committed Burst Size (CBS) for that PHB. Packets that are within the CIR or CBS for the given PHB are marked as in profile. Packets to be output over a given port that are not in profile are metered by a common Surplus Information Rate (SIR) meter, which is used to meter commonly excess packets from all PHBs configured through that port. By using a common SIR meter to meter out of profile packets for all PHBs on a given port, it is possible to allow packets from multiple PHBs to share the surplus bandwidth on a link connected to that port fairly, while not allocating bandwidth to PHBs that do not require surplus bandwidth. Token buckets may be used to implement the meters.

Abstract: A P device interworks CE devices connected to the P device using different types of data links. The P device learns the address of a local CE device by monitoring the control messages, such as address resolution messages, originating from the local device. The P device may share the address of a local CE device with another local CE device by initiating a control message or responding to a control message issued by one of the local CE devices. This latter mechanism in effect hides the heterogeneous nature of the network.

Abstract: A method and apparatus are provided for creating a virtual hierarchical local area network. The method and apparatus provide a hierarchical framing technique that allows a network architecture to realize a local area network hierarchy within the network. In this manner, a first local area network hierarchy is defined by communication in a first frame format between a first set of network devices and a second set of network devices. A second local area network hierarchy is defined by communication in a second frame format between members of the second set of network devices. The second frame format includes the fields of a frame in the first frame format that is used to communicate between the first set of communication devices and the second set of communication devices.

Abstract: Token Ring network packet having a header and an information field is prepared for transmission over an Ethernet network by the steps of removing the header information from the Token Ring packet, and associating a second header with the information field of the Token Ring packet, wherein the second header is compatible with the Ethernet network. More particularly, to prepare an IEEE 802.5 Token Ring network packet for transmission on an Ethernet network the Access Control ("AC") and Frame Control ("FC") fields are removed, the order of the destination address ("DA") field is reversed, the order of the source address ("SA") field is reversed, a Virtual Local Area Network ("VLAN") type field is added, a VLAN identification ("ID") field is added, and a length value field is added. The information field from the Token Ring packet is retained.