摘要:
Techniques are described for implementing one or more logical routers within a single physical routing device. These logical routers, as referred to herein, are logically isolated in the sense that they achieve operational and organizational isolation within the routing device without requiring the use of additional or redundant hardware, e.g., additional hardware-based routing controllers. The routing device may, for example, include a computing platform, and a plurality of software process executing within the computing platform, wherein the software processes operate as logical routers. The routing device may include a forwarding component shared by the logical routers to forward network packets received from a network in accordance with the forwarding tables.
摘要:
In general, techniques are described for dynamically configuring cross-domain pseudowires (PWs). A network device positioned between a first domain and a second domain of a computer network may implement the techniques. The intermediate network device comprises at least one interface and an LDP module, a transformation module and a routing protocol module. The interface receives a label distribution protocol (LDP) message that includes data for configuring a cross-domain PW from a first provider edge (PE) device of the first domain. The LDP module parses the received LDP message to extract the cross-domain PW configuration data. The translation module transforms the extracted data to conform to routing protocol extensions for advertising the cross-domain PW configuration data. The routing protocol module forms a routing protocol message that includes the transformed data. The interface outputs the routing protocol message to the second intermediate device of the second domain to establish the cross-domain PW.
摘要:
A first network device creates a protection path to a second network device associated with a first service site, and creates a pseudowire between the first service site and a second service site via the first network device and the second network device. The first network device also detects a failure between the first network device and the first service site, and forwards traffic, provided by the pseudowire between the first service site and the second service site, via the protection path. The second network device uses the traffic on the protection path as a trigger to activate a link between the second network device and the first service site.
摘要:
A first network device creates a protection path to a second network device associated with a first service site, and creates a pseudowire between the first service site and a second service site via the first network device and the second network device. The first network device also detects a failure between the first network device and the first service site, and forwards traffic, provided by the pseudowire between the first service site and the second service site, via the protection path. The second network device uses the traffic on the protection path as a trigger to activate a link between the second network device and the first service site.
摘要:
Label distribution protocol (LDP) signaled label-switched paths (LSPs) are supported without requiring information about remote autonomous systems (ASs) to be injected into the local interior gateway protocol (IGP). This may be done by (i) decoupling a forwarding equivalency class (FEC) element from the routing information, and (ii) specifying a next hop on which the FEC relies. An LDP messaging structure (e.g., an LDP type-length-value (TLV)) that includes a label, FEC information (e.g., a host address or prefix of an egress LSR of the LSP) and a next hop (e.g., a host address or prefix of a border node, such as an AS border router (ASBR)) may be provided. This messaging structure may be included in one or more of (a) label mapping messages, (b) label withdraw messages, and (c) label release messages. If an LDP message including the expanded LDP messaging structure is received at a node, the node may determine whether or not to propagate the LSP using the next hop information, rather than the FEC information. If, on the other hand, the LDP message includes a normal LDP messaging structure, the node may determine whether or not to propagate the LSP as usual.
摘要:
The invention is directed to techniques for failsafe management of periodic communications between network devices. A first network device, for example, establishes with a second network device a first response interval by which the first device responds to a message received from the second device. Prior to commencing a software upgrade, the first device determines whether the event requires an interval of time during which the first device cannot respond to the message within the established first response interval. Based on the determination and prior to commencing the upgrade, the first device establishes with the second device a second response interval that equals or exceeds the first response interval. Upon completion of the event, the first device establishes with the second device a third response interval. The first network device therefore may automatically adjust response intervals to accommodate upgrades that may cause unnecessary thrashing.
摘要:
The label distribution protocol (LDP) is extended to set up a point to multi-point (P2MP) label switched path (LSP) across a computer network from a source network device to one or more destination network devices. LDP is extended to create a P2MP label map message containing a label and a P2MP forwarding equivalence class (FEC) element having a root node address and an identifier. The P2MP FEC element may, for example, associate an address of the root node of the P2MP LSP with an opaque identifier. The P2MP FEC element uniquely identifies the P2MP LSP. The P2MP FEC element may be advertised with a label in a P2MP label map message. A source network device or the destination network devices may initiate setup and teardown of the P2MP LSP. The P2MP label map messages may be propagated from the destination network devices to the source network device.
摘要:
A router receives a control plane message for constructing a first LSP to a destination within a network that conforms to a first type of LSP. The control plane message includes a label for the first LSP and an identifier that identifies a first type of data traffic. The router receives a second control plane message for constructing a second LSP that conforms to the first type of LSP. The second control plane message includes a label for the second LSP and an identifier that identifies a second type of data traffic. The router installs forwarding state in accordance with policies that associate the first and second types of data traffic with different LSPs of a second type that each traverse different paths through the network, and forwards packets via the interface in accordance with the installed forwarding state.
摘要:
Techniques are described for performing non-revertive failover with network devices. A network device including a control unit and interface cards receives routing information protocol (RIP) updates each having a metric value. The control unit signals bidirectional forwarding detection (BFD) sessions based on the metric values of each of the RIP updates with, for example, a media gateway. The control unit also selectively installs a RIP route based on the metric values. The media gateway monitors the BFD sessions, and upon failure of an active BFD session, indicates the network device to perform non-revertive failover by sending a revised plurality of RIP updates. The network device performs non-revertive failover according to the revised plurality of RIP updates. Because of the flexibility of BFD, the network device need not revert back to a previous RIP route, therefore curtailing excessive failover.
摘要:
Methods and apparatus for implementing bi-directional logical signal interfaces (LSIs) in communications systems which use uni-directional label switched paths (LSPs), e.g., MPLS networks, are described. To implement an LSI, two uni-directional LSPs between the same end points, e.g., routers, and extending in opposite directions, are associated together. The association of LSPs may be done by setting LSI configuration information in the routers at both ends of an LSI. Each router at the end of an LSI serves as an egress router for one of the LSPs associated with the LSI and an ingress router for the other LSP associated with the LSI. To enable an egress router to determine which, if any, LSI a packet or message corresponds to, a real as opposed to a null label is used when sending packets over an LSI LSP to an LSI LSP egress router.