摘要:
In one embodiment, operations analysis of packet groups identified based on timestamps is performed. One embodiment includes sending a plurality of sent timeframe groups of a plurality of time-stamped packets from a first packet network node towards a second packet network node in a network and recording first information associated with each of the plurality of said sent timeframe groups of the plurality of time-stamped packets. The second network node receives a plurality of received timeframe groups of a received plurality of time-stamped packets of said sent plurality of time-stamped packets and recording second information associated with each of the plurality of said received timeframe groups of the received plurality of time-stamped packets. Operations analysis based on one or more operations characteristics of said first information and said second information to produce analysis results.
摘要:
A technique efficiently selects a Path Computation Element (PCE) to compute a path between nodes of a computer network. The PCE selection technique is illustratively based on dynamic advertisements of the PCE's available path computation resources, using (i) a low-pass filter algorithm to compute such resources, and (ii) threshold determinations to control distribution of those advertisements. To that end, the novel technique enables one or more PCEs to dynamically send (advertise) their available path computation resources to a Path Computation Client (PCC) by way of the controlled advertisements. In addition, the technique enables the PCC to efficiently select a PCE (or set of PCEs) to service a path computation request based upon those available resources.
摘要:
An example method includes detecting a failure at a first network element, the failure is associated with a link between the first network element and a second network element. The method also includes generating a list of network elements to be notified based on the failure, the second network element is included on the list. The method further includes generating an alarm indication signal (AIS) message, the AIS message identifies a plurality of tunnels affected by the failure. The AIS message is communicated to the second network element. In more detailed embodiments, each link between the first network element and the second network element includes a globally unique link identifier, which includes an associated autonomous system number. The globally unique link identifier can represent a string to be associated with the plurality of tunnels, the globally unique link identifier includes a source address and a destination address.
摘要:
A mechanism to alleviate bandwidth fragmentation in a network employing path computation element(s) to place MPLS Traffic Engineering tunnels. One application is a multiple Autonomous System or multiple area network employing distributed computation of MPLS Traffic Engineering LSPs. A particular path computation element may determine that bandwidth fragmentation is present based on monitoring of path computation failures where desired paths are blocked due to bandwidth constraints. In response to the detected bandwidth fragmentation condition, the path computation element floods a routing notification within its Autonomous System or area. Nodes respond to the routing notification by requesting reoptimization of their own previously requested Traffic Engineering LSPs allowing the path computation element an opportunity to alleviate bandwidth fragmentation.
摘要:
A graceful shutdown technique modifies a routing protocol to allow an intermediate node, such as a router, to announce to its peer routers (peers) its intention to be gracefully shutdown and removed from service in a network. By announcing its intention to be removed from service, the shutdown router closes (terminates) all connections with its peers and all original routes advertised on those connections are removed (withdrawn) from service. According to the inventive technique, the shutdown router may continue forwarding packets over the network for a “grace” period of time, i.e., the router maintains the validity of those original routes so that packets mapped to the routes are not dropped (at least during the grace period). The grace period also allows backup paths to be propagated to each peer and put into service prior to a final withdrawal of the shutdown router's paths from a forwarding information base of the peer. Thus, the grace period enables the network to continue using the shutdown router as a next hop as it re-converges to use the alternate, backup paths.
摘要:
Systems and methods for preemption of Traffic Engineering LSPs such that preemption decisions are made in a coordinated fashion along the path of a new LSP and computation of a new path for a preempted LSP can take advantage of knowledge of newly unavailable links. The efficiency of the preemption mechanism is greatly increased and the undesirable effects of heterogeneous preemption decisions are limited. The amount of signaling may also be significantly reduced. In one implementation, these advantages are achieved by exploiting an upstream preemption feedback mechanism that uses an incremental timer to delay preemption decisions until feedback is available.
摘要:
In one embodiment, an access component of a local network edge device receives traffic, and generates a frame for the traffic that includes a remote context label that identifies an access component of the remote network edge device to which the traffic is to be forwarded upon arrival at the remote network edge device, and a virtual circuit label corresponding to a particular virtual service of the traffic. The local network edge device forwards the frame towards the remote network edge device. In another embodiment, the frame may be received at a core component of the remote network edge device, an in response to the remote context label identifying an access component of the remote network edge device, forwarded to the access component, which determines the particular virtual service, and forwards the traffic from the frame out the access component towards an endpoint for the traffic.
摘要:
In one embodiment, a router generates a notification message that indicates the router is to be gracefully removed from service. The router sends the notification message to peers of the router in a network. The router then continues to forward packets for a grace period after sending the notification message, to permit backup paths to be propagated to peers, and to be put into service, prior to withdrawal from service of paths through the router. Thereafter, the router is removed from service at the expiration of the grace period.
摘要:
In one embodiment, a protected switching provider edge (S-PE) and a backup S-PE may be operated, where the protected S-PE has at least one multi-segment pseudowire (MS-PW) and is between a first and second provider edge (PE) on the MS-PW. To protect the protected S-PE, the first and second PE may be informed of the backup S-PE and a backup label to reach the second and first PE, respectively, via the backup S-PE to remain on the MS-PW. Upon detecting loss of connectivity with the protected S-PE, the first and/or second PE may forward packets of the MS-PW to the backup S-PE with the corresponding backup label to reach the second or first PE, respectively, on the MS-PW.
摘要:
In one embodiment, a protected switching provider edge (S-PE) and a backup S-PE may be operated, where the protected S-PE has at least one multi-segment pseudowire (MS-PW) and is between a first and second provider edge (PE) on the MS-PW. To protect the protected S-PE, the first and second PE may be informed of the backup S-PE and a backup label to reach the second and first PE, respectively, via the backup S-PE to remain on the MS-PW. Upon detecting loss of connectivity with the protected S-PE, the first and/or second PE may forward packets of the MS-PW to the backup S-PE with the corresponding backup label to reach the second or first PE, respectively, on the MS-PW.