Path Encoding in Segment Routing

Giorgetti, A.; Castoldi, P.; Cugini, F.; Nijhof, J.H.B.; Lazzeri, Francesco; Bruno, Gianmarco

doi:10.1109/glocom.2014.7417097

Cited by 10 publications

(6 citation statements)

References 15 publications

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“…Segment routing is used to force probe packets to traverse specific paths. Giorgetti et al [25] propose algorithms for segment routing label stack computation that guarantee minimum label stack depth. Such use cases are beyond our work.…”

Section: A Segment Routing and Tementioning

confidence: 99%

Node-Constrained Traffic Engineering: Theory and Applications

Trimponias

Yan

et al. 2019

IEEE/ACM Trans. Networking

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Traffic engineering (TE) is a fundamental task in networking. Conventionally, traffic can take any path connecting the source and destination. Emerging technologies such as segment routing, however, use logical paths going through a predetermined set of middlepoints. Inspired by this, in this work we introduce the problem of node-constrained TE, where traffic must go through a set of middlepoints, and study its theoretical fundamentals. We show that the general node-constrained TE that constrains the traffic to take paths going through one or more middlepoints is NP-hard for directed graphs but strongly polynomial for undirected graphs, unveiling a profound dichotomy between the two cases. We additionally investigate the popular variant of node-constrained TE that uses shortest paths between middlepoints, and show that the problem can now be solved in weakly polynomial time for a fixed number of middlepoints. Yet if we constrain the end-to-end paths to be acyclic, the problem can become NP-hard. This explains why existing work focuses on the computationally tractable variant. An important application of our work concerns the computational complexity of flow centrality, first proposed in 1991 by Freeman et al. [21]: we show that it is NP-hard for directed but strongly polynomial for undirected graphs. Finally, we investigate the middlepoint selection problem in general node-constrained TE. We introduce group flow centrality as a solution concept for multi-commodity networks, study its complexity, and show that it is monotone but not submodular for both directed and undirected graphs. Our work provides a thorough theoretical treatment of nodeconstrained TE and its applications.

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Section: A Segment Routing and Tementioning

confidence: 99%

Node-Constrained Traffic Engineering: Theory and Applications

Trimponias

Yan

et al. 2019

IEEE/ACM Trans. Networking

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“…Giorgetti et al [40] proposed two algorithms that outputs two label stack with the same size, one is for forward direction (src→dst) and second one the reverse path (dst→src). Their assumption is that the direct link between two nodes is the shortest path.…”

Section: Segment Encoding Algorithm Comparisonmentioning

confidence: 99%

Failure Recovery In SDN: A Segment Routing Based Link Protection Approach

Enan¹

2021

Preprint

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The present computer network has been evolved into a complex structure with a growing challenge to manage and scale modern day’s requirements. A new approach to tackle these difficulties is SDN, which empowers network with programmability and is designed to perform fine grained traffic forwarding decisions. However, similar to the need of traditional networks, fault tolerance is necessary to achieve high availability. In this thesis, we propose a link protection method based on the Segment Routing (SR) for rapid failure recovery in OpenFlow based SDN. Our proposed scheme performs local recovery at the switch level without the controller intervention, thus significantly reducing the total recovery time. Additionally, it reduces initial load on the controller while proactively computing the backup paths by minimizing the algorithm complexity. Moreover, memory efficiency is achieved by using a per-link protection with aggregated flow rules instead of traditional per-flow based protection mechanism. In Segment Routing, we may encounter the limitation on the size of the label stack, known as Segment List Depth (SLD). Therefore, we also propose an efficient label encoding algorithm to mitigate the SLD impact.

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“…The work in [9] implemented SR in carrier grade Ethernet networks including a detailed simulation studies. Algorithms to compute the segment list encoding a given path are proposed in [2,12,13]. Specifically, [2] and [13] propose the utilization of an auxiliary graph model representing the available network segments for computing the segment list, whereas the work in [12] proposes a greedy algorithm to compute the segment list of minimum depth.…”

Section: Previous Work On Segment Routingmentioning

confidence: 99%

“…Algorithms to compute the segment list encoding a given path are proposed in [2,12,13]. Specifically, [2] and [13] propose the utilization of an auxiliary graph model representing the available network segments for computing the segment list, whereas the work in [12] proposes a greedy algorithm to compute the segment list of minimum depth. The works in [14,15] formulate a multi-commodity flow problem to evaluate the benefits of SR.…”

Section: Previous Work On Segment Routingmentioning

confidence: 99%

“…During packet forwarding, at node C, label C is popped, leaving F as the new top label along the rest of the path. Note that the selection of either paths can be performed in an extremely dynamic way by simply enforcing to each incoming packet at node A the proper segment list, without requiring complex and time consuming control plane operations [4,5,12].…”

Section: Previous Work On Segment Routingmentioning

confidence: 99%

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Segment Routing in multi-layer networks

Castoldi

Giorgetti

Sgambelluri

et al. 2017

2017 19th International Conference on Transparent Optical Networks (ICTON)

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Segment Routing (SR) has been recently introduced to enable efficient traffic engineering while simplifying control plane operations. Thanks to the source routing paradigm, traffic flows can be dynamically routed along the network, effectively exploiting network resources. In this paper, dynamic SR operations for multi-layer networking are presented and experimentally demonstrated. In particular, SR-based dynamic optical bypass and effective load balancing are validated in a multi-layer network testbed, showing enhanced capabilities to achieve effective resource utilization while guaranteeing lightweight control operations.

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Path Encoding in Segment Routing

Cited by 10 publications

References 15 publications

Node-Constrained Traffic Engineering: Theory and Applications

Node-Constrained Traffic Engineering: Theory and Applications

Failure Recovery In SDN: A Segment Routing Based Link Protection Approach

Segment Routing in multi-layer networks

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