Resilient routing using MPLS and ECMP

Abstract-The increasing commercial importance of the Internet together with a rising number of real-time and mission-critical applications make fast resilience mechanisms a major issue for IP network planning and operation. Current IP-layer rerouting is too slow to meet these requirements. Therefore we propose a new approach combining two protocols readily available in every router: The fast local reaction of the EqualCost-Multiple-Path extension of OSPF operating on a network with its connectivity enhanced by the introduction of a limited number of MPLS paths in critical areas of the topology. We describe an algorithm for the determination of these MPLS paths and its optimization to obtain an equal loading of the physical network links. Numerical results on the basis of real network topologies show that already a small number of MPLS paths can offer sufficient connectivity for fast protection via ECMP. Furthermore, it can be proven that the bandwidth overhead necessary for this enhanced network resilience is as small as possible

Optical Network Design for a Multiline-Rate Carrier-Grade Ethernet Under TransmissionRange Constraints

Abstract—Ethernet is a success story in local area networks (LAN). Efforts for extending its boundaries beyond LAN to the carriers ’ backbone networks are in progress. We study the problem of designing reliable and cost-efficient high-rate (100 Gbit/s) carrier-grade Ethernet in a multiline-rate optical network under signal transmission-range constraints. Reliability is achieved using shared-path protection at the connection level (Ethernet tunnel in this study). We construct an auxiliary graph, called mixed topology (MT), using which it is possible to: 1) identify traffic grooming possibilities; 2) select a path which requires the minimum amount of 3R regeneration; and 3) effectively choose the data rate of the channel to be established. Our algorithms, tested on the 17-node German network, resulted in lower network cost and higher resource utilization compared with other schemes. Index Terms—3R regeneration, carrier grade, Ethernet, Etherpath, link stretching, mixed topology (MT), multiline rate, signa

Methodology and input availability parameters for calculating OpEx and CapEx costs for realistic network scenarios

The availability requirements for today's networks are very high. Higher availability often comes with a higher cost. We describe several steps required for estimating the costs of realistic network scenarios. Capital expenditures (CapEx) and operational expenditures (OpEx) are classified. An activity-based approach is used to quantify the cost of the event-driven operational processes such as repair and service provisioning. We discuss activity duration and availability parameters as required input data, which are necessary for calculating the processes' costs for realistic network scenarios. The relevant availability measures for an IP-over-Optical network are described using a triplet representation with optimistic, nominal, and conservative values. The model is applied to a reference German network scenario

1 Gbit/s transmission with 6.3 bit/s/Hz spectral efficiency in a 100m standard 1 mm step-index plastic optical fibre link using adaptive multiple sub-carrier modulation

Transmission of 1 Gbit/s over 100 m of SI-POF is demonstrated. To the authors’ knowledge this sets a new record. The bandwidth limitation of the SI-POF is compensated by spectrally efficient adaptive multiple subcarrier modulation

Carrier grade metro ethernet networks

This paper gives an overview on actual trends and deployments of carrier- grade Ethernet in metro, access, and core networks. This includes the related motivation, concepts, and technologies as well as open issues regarding research, development, and standardization. Ethernet as a packet-based, connection-oriented technology is deployed for metro networks worldwide today. This is driven by the massive increase of (IP- based) data traffic and the related applications. The Ethernet deployments aim at most cost-efficient data service provisioning and the migration of all legacy Layer-2 services towards a unified platform. The goal is a massive reduction of both, CapEx and OpEx. Network operators and service providers impose increased requirements regarding scalability, quality of service including reliability and availability, and Operations, Administration, and Maintenance (OAM) features on their metro Ethernet solutions. These requirements are usually referred to as carrier-grade or transport Ethernet. Metro Ethernet services as deployed today mainly consist of Ethernet Private Lines (EPL) or Ethernet Virtual Private LANs (EVPLAN). These can provide dedicated LAN extension or LAN- like connectivity via IP/MPLS, respectively. A different approach is Pseudowire Emulation Edge-to-Edge (PWE3) which allows MPLS transport of Ethernet and other packet services as well as synchronous TDM services. Various network architecture and protocol options exist to migrate from metro SONET/SDH and WDM networks towards even more Ethernet-centric and - optimized networks. These include Layer-2 transport like Transport MPLS (T-MPLS), Provider Backbone Transport (PBT), and Ethemet-over- SONET/SDH/WDM/OTH. These services are currently under investigation or being standardized, and they will also migrate into long-haul and backbone networks. These approaches have common requirements regarding network and control planes (e.g., ASON/GLMPS, GELS, T-MPLS). Thus, the corresponding management and control mechanisms have to have an integrated view on the lower 3 network layers. Further challenges for transport Ethernet result from upcoming technology steps like 100 Gbps Ethernet. Again, carrier-grade requirements and interworking aspects with transport networks have to be taken into account

107-Gb/s full-ETDM transmission over field installed fiber using vestigial sideband modulation

107-Gb/s full-ETDM transmission is shown over a 160-km field installed fiber link. A high tolerance towards narrowband optical filtering is demonstrated using vestigial sideband modulation to minimize the spectral width