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High-Performance Switch-Routers
Published in James Aweya, Designing Switch/Routers, 2023
A number of enhancements have been proposed within the Internet Engineering Task Force (IETF) to improve the resiliency of IP. Bidirectional Forwarding Detection (BFD) [RFC5880] [RFC5881], is a protocol for detecting faults in the bi-directional path between two forwarding engines, including faults on physical interfaces, sub-interfaces, data links and, to the extent possible, the forwarding engines themselves. It is intended to be independent of media, data protocols and routing protocols, and to operate with very low latency. BFD provides low-overhead detection of faults even on physical media that do not support failure detection of any kind, such as static routes, virtual circuits, tunnels and Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs). For example, BFD enables Ethernet to detect media faults, fault detection capabilities that Ethernet was not originally designed to support.
Transport Network
Published in Saad Z. Asif, 5G Mobile Communications Concepts and Technologies, 2018
One of the key features of MPLS-TP is existing transport network-like OAM functionality. From the very beginning of MPLS-TP development, there were two camps defining the OAM functions. The IETF was focusing on developing extensions to existing MPLS OAM tools and creating some new measurement and fault management tools. That includes extending Bidirectional Forwarding Detection (BFD) for proactive continuity check and connectivity verification and extending LSP Ping for on-demand connectivity verification and route tracing.
Integration of the elements of a distributed IT system with a computer network core using island topology
Published in Enterprise Information Systems, 2021
M. Bolanowski, A. Paszkiewicz, A. Kraska
The architecture of current connection networks is mainly based on dynamically configurable local and sensor networks (Casado et al. 2001; Jiang, Gu, and Wu 2017) and static WANs that are mostly unchanged. However, we propose a completely different approach in this paper, where the network core undergoes a relatively frequent change and autonomous local networks remain static. Currently, the topology of core corporate networks is based on static network infrastructure and virtual private network (VPN) channels. Possible changes are made at the network layer in the scope of the routing paths. The static approach can only consider initial conditions, which are usually inadequate for dynamic changes in the network infrastructure. However, in reconfiguration, it is necessary to distinguish the mechanisms used based on the layer of the ISO/OSI model on which they are implemented. In the case of a physical layer, only available solutions enable the switching or translation of individual optical wavelengths between different links (Dutta and Rouskas 2002; Thylen, Karlsson, and Nilsson 1996; Ho and Mouftah 2002). This approach imposes the use of wavelength-division multiplexing (WDM) or dense wavelength-division multiplexing (DWDM) (Zhang, Xu, and Wu 2007; Yang and Verchere 2001; Durán et al. 2007) and does not consider other available solutions. In layer 2, multi-protocol label switching (MPLS) (Xiao et al. 2000; Girão-Silva et al. 2015) and QoS mechanisms are available, which change the transmission path based on the connection quality parameters (Bahnasse et al. 2018; Fathy, Firouzjaee, and Raahemifar 2012). This solution also imposes the use of MPLS-based devices throughout the core connecting individual islands. Other network mechanisms available in layer 2, including link aggregation control protocol (LACP), dual home, and multi-chassis link aggregation group (MC-LAG), are locally applicable. In layer 3, equal-cost multi-path (ECMP) mechanism is available, which allows the balancing of network flows at the routing path level (Németh, Kőrösi, and Rétvári 2013; Resende Rocha, Junior, and Vieira 2018; Bocci, Cowburn, and Guillet 2008). Meanwhile, the combination of routing protocols with bidirectional forwarding detection (BFD) mechanism speeds up and forces a change in the routing path in cases where there are problems with a particular communication link (Tavernier et al. 2009). Thus, the reconfiguration and current evaluation of connections occur in a given layer of the ISO/OSI model. In the proposed approach (cross-layer), selected parameters from different layers used to set up the connection can be analysed. However, currently available solutions do not include such an approach.