In one embodiment, an apparatus includes one or more internal interfaces in communication with one or more network devices in a first network site through a Layer 2 link, an overlay interface in communication through a Layer 3 link with a core network connected to one or more other network sites, and a table mapping addresses for network devices in the other network sites to addresses of edge devices in the same network site as the network device. The apparatus further includes a processor operable to encapsulate a packet received at one of the internal interfaces and destined for one of the network devices in the other network sites, with an IP header including a destination address of the edge device mapped to the destination network device, and forward the encapsulated packet to the core network.

Overlay transport virtualization

In WDM optical networks, the physical layer impairments (PLIs) and their significance depend on network type-opaque, translucent, or transparent; the reach-access, metro, or core/long-haul; the number and type of network elements-fiber, wavelengths, amplifiers, switching elements, etc.; and the type of applications-real-time, non-real time, missioncritical, etc. In transparent optical networks, PLIs incurred by non-ideal optical transmission media accumulate along an optical path, and the overall effect determines the feasibility of the lightpaths. If the received signal quality is not within the receiver sensitivity threshold, the receiver may not be able to correctly detect the optical signal and this may result in high bit-error rates. Hence, it is important to understand various PLIs and their effect on optical feasibility, analytical models, and monitoring and mitigation techniques. Introducing optical transparency in the physical layer on one hand leads to a dynamic, flexible optical layer with the possibility of adding intelligence such as optical performance monitoring, fault management, etc. On the other hand, transparency reduces the possibility of client layer interaction with the optical layer at intermediate nodes along the path. This has an impact on network design, planning, control, and management. Hence, it is important to understand the techniques that provide PLI information to the control plane protocols and that use this information efficiently to compute feasible routes and wavelengths. The purpose of this article is to provide a comprehensive survey of various PLIs, their effects, and the available modeling and mitigation techniques. We then present a comprehensive survey of various PLI-aware network design techniques, regenerator placement algorithms, routing and wavelength assignment algorithms, and PLI-aware failure recovery algorithms. Furthermore, we identify several important research issues that need to be addressed to realize dynamically reconfigurable next-generation optical networks. We also argue the need for PLI-aware control plane protocol extensions and present several interesting issues that need to be considered in order for these extensions to be deployed in real-world networks.

Physical layer impairment aware routing (PLIAR) in WDM optical networks: issues and challenges

A system comprising a plurality of path computation elements (PCEs) configured to communicate with an ingress node, jointly compute a core tree for an inter-domain point-to-multipoint (P2MP) tree across a plurality of network domains, and independently compute a plurality of sub-trees in at least some of the network domains, wherein the core tree connects the ingress node to a boundary node (BN) in each one of the network domains that have a destination node and each sub-tree connects the BN to a plurality of destination nodes in one of the network domains that have a destination node.

System and method for point to multipoint inter-domain multiprotocol label switching traffic engineering path calculation

Services such as content distribution, distributed databases, or
inter-data center connectivity place a set of new requirements on the
operation of networks. They need on-demand and application-specific
reservation of network connectivity, reliability, and resources (such
as bandwidth) in a variety of network applications (such as point-to-
point connectivity, network virtualization, or mobile back-haul) and
in a range of network technologies from packet (IP/MPLS) down to
optical. An environment that operates to meet these types of
requirements is said to have Application-Based Network Operations
(ABNO). ABNO brings together many existing technologies and may be
seen as the use of a toolbox of existing components enhanced with a
few new elements. This document describes an architecture and
framework for ABNO, showing how these components fit together. It
provides a cookbook of existing technologies to satisfy the
architecture and meet the needs of the applications.

/pdf/a-pce-based-architecture-for-application-based-network-4xfcd1zl0b.pdf

A PCE-Based Architecture for Application-Based Network Operations

A path control device includes a TE database and a local database for storing topology information showing states of use of links in a network, a topology information collection unit collecting the topology information of the respective communication nodes therefrom and updating the TE database by the topology information, a path solution unit determining a path of the network referring to the local database, an internal update unit recognizing a link included in the determined path and updating a local database by information as to said link, and an update determination unit matching the topology information of both the databases by comparing both the databases.

Network path control system, path control device, and path control method

A network may comprise multiple layers. It is important to globally
optimize network resource utilization, taking into account all layers,
rather than optimizing resource utilization at each layer
independently. This allows better network efficiency to be achieved
through a process that we call inter-layer traffic engineering. The
Path Computation Element (PCE) can be a powerful tool to achieve
inter-layer traffic engineering. This document describes a framework
for applying the PCE-based architecture to inter-layer Multiprotocol
Label Switching (MPLS) and Generalized MPLS (GMPLS) traffic
engineering. It provides suggestions for the deployment of PCE in
support of multi-layer networks. This document also describes network
models where PCE performs inter-layer traffic engineering, and the
relationship between PCE and a functional component called the Virtual
Network Topology Manager (VNTM).

Framework for PCE-Based Inter-Layer MPLS and GMPLS Traffic Engineering

Framework for PCE-Based Inter-Layer MPLS and GMPLS Traffic Engineering.

The Path Computation Element (PCE) provides functions of path
computation in support of traffic engineering (TE) in Multi-Protocol
Label Switching (MPLS) and Generalized MPLS (GMPLS) networks. When a
Path Computation Client (PCC) requests a PCE for a route, it may be
useful for the PCC to specify, as constraints to the path computation,
abstract nodes, resources, and Shared Risk Link Groups (SRLGs) that
are to be explicitly excluded from the computed route. Such
constraints are termed "route exclusions". The PCE Communication
Protocol (PCEP) is designed as a communication protocol between PCCs
and PCEs. This document presents PCEP extensions for route exclusions.
[STANDARDS-TRACK]

/pdf/extensions-to-the-path-computation-element-communication-28zg91uo5r.pdf

Extensions to the Path Computation Element Communication Protocol (PCEP) for Route Exclusions

An optical network (1001) includes: a plurality of optical edge routers (1003) having optical path establishing means (1316) and connecting an external IP network (1002) to the optical network (1001); and a plurality of optical cross connect devices having switching means on optical path basis for connecting the edge routers (1003) to one another by an optical path. The optical edge routers (1003) include both of (1) an optical network control instance INSp having topology information in the optical network (1001) and performing optical path routing and signaling and (2) an IP network instance INSi having an external IP network routing table and operating a routing protocol between the edge routers and the external IP network. With this configuration, it is possible to realize a multi-layer linkage function and provide an optical network having a high stability.

Optical network, optical edge router, program thereof, cut through method, and edge router

This document analyzes various schemes to realize Multiprotocol Label
Switching (MPLS) and Generalized MPLS (GMPLS) Label Switched Path
(LSP) recovery in multi-domain networks based on the existing
framework for multi-domain LSPs. The main focus for this document is
on establishing end-to-end diverse Traffic Engineering (TE) LSPs in
multi-domain networks. It presents various diverse LSP setup schemes
based on existing functional elements.

Tomonori Takeda

Papers

Framework for PCE-Based Inter-Layer MPLS and GMPLS Traffic Engineering

Framework for PCE-Based Inter-Layer MPLS and GMPLS Traffic Engineering.

Extensions to the Path Computation Element Communication Protocol (PCEP) for Route Exclusions

Optical network, optical edge router, program thereof, cut through method, and edge router

Analysis of Inter-Domain Label Switched Path (LSP) Recovery