Network service chaining with efficient network function mapping based on service decompositions

Network Service Chaining (NSC) is a service concept which promises increased flexibility and cost-efficiency for future carrier networks. The two recent developments, Network Function Virtualization (NFV) and Software-Defined Networking (SDN), are opportunities for service providers to simplify the service chaining and provisioning process and reduce the cost (in CAPEX and OPEX) while introducing new services as well. One of the challenging tasks regarding NFV-based services is to efficiently map them to the components of a physical network based on the services specifications/constraints. In this paper, we propose an efficient cost-effective algorithm to map NSCs composed of Network Functions (NF) to the network infrastructure while taking possible decompositions of NFs into account. NF decomposition refers to converting an abstract NF to more refined NFs interconnected in form of a graph with the same external interfaces as the higher-level NF. The proposed algorithm tries to minimize the cost of the mapping based on the NSCs requirements and infrastructure capabilities by making a reasonable selection of the NFs decompositions. Our experimental evaluations show that the proposed scheme increases the acceptance ratio significantly while decreasing the mapping cost in the long run, compared to schemes in which NF decompositions are selected randomly

Resilient availability and bandwidth-aware multipath provisioning for media transfer over the internet (Best Paper Award)

Traditional routing in the Internet is best-effort. Path differentiation including multipath routing is a promising technique to be used for meeting QoS requirements of media intensive applications. Since different paths have different characteristics in terms of latency, availability and bandwidth, they offer flexibility in QoS and congestion control. Additionally protection techniques can be used to enhance the reliability of the network. This paper studies the problem of how to optimally find paths ensuring maximal bandwidth and resiliency of media transfer over the network. In particular, we propose two algorithms to reserve network paths with minimal new resources while increasing the availability of the paths and enabling congestion control. The first algorithm is based on Integer Linear Programming which minimizes the cost of the paths and the used resources. The second one is a heuristic-based algorithm which solves the scalability limitations of the ILP approach. The algorithms ensure resiliency against any single link failure in the network. The experimental results indicate that using the proposed schemes the connections availability improve significantly and a more balanced load is achieved in the network compared to the shortest path-based approaches

Single failure resiliency in greedy routing

Using greedy routing, network nodes forward packets towards neighbors which are closer to their destination. This approach makes greedy routers significantly more memory-efficient than traditional IP-routers using longest-prefix matching. Greedy embeddings map network nodes to coordinates, such that greedy routing always leads to the destination. Prior works showed that using a spanning tree of the network topology, greedy embeddings can be found in different metric spaces for any graph. However, a single link/node failure might affect the greedy embedding and causes the packets to reach a dead end. In order to cope with network failures, existing greedy methods require large resources and cause significant loss in the quality of the routing (stretch loss). We propose efficient recovery techniques which require very limited resources with minor effect on the stretch. As the proposed techniques are protection, the switch-over takes place very fast. Low overhead, simplicity and scalability of the methods make them suitable for large-scale networks. The proposed schemes are validated on large topologies with properties similar to the Internet. The performances of the schemes are compared with an existing alternative referred as gravity pressure routing

Robust geometric forest routing with tunable load balancing

Although geometric routing is proposed as a memory-efficient alternative to traditional lookup-based routing and forwarding algorithms, it still lacks: i) adequate mechanisms to trade stretch against load balancing, and ii) robustness to cope with network topology change. The main contribution of this paper involves the proposal of a family of routing schemes, called Forest Routing. These are based on the principles of geometric routing, adding flexibility in its load balancing characteristics. This is achieved by using an aggregation of greedy embeddings along with a configurable distance function. Incorporating link load information in the forwarding layer enables load balancing behavior while still attaining low path stretch. In addition, the proposed schemes are validated regarding their resilience towards network failures

Towards content-centric geometric routing

Content delivery is a crucial feature of existing cloud and telecom networks. This is confirmed by the tremendous success of media streaming services such as Spotify and Netftix, as well as the content and file-distribution systems such as BitTorrent. A recurring problem in these type of network services is about keeping the protocol overhead as low as possible while maximizing the efficiency of such systems in terms of network delay to customers. In this paper we propose the use of a routing system-inferred coordinate system to improve: i) content server selection upon receiving content requests, and ii) the mapping of content to servers/caches. We describe the required protocol mechanisms, and evaluate potential gains using coordinates of Geometric Tree Routing and compare it to pure IP-based mechanisms or measurement-based content systems relying on coordinates. The proposed approach can be further extended in order to include alternate geometric systems for example supporting hyperbolic geometries

Multi-domain service orchestration over networks and clouds: a unified approach

End-to-end service delivery often includes transparently inserted Network Functions (NFs) in the path. Flexible service chaining will require dynamic instantiation of both NFs and traffic forwarding overlays. Virtualization techniques in compute and networking, like cloud and Software Defined Networking (SDN), promise such flexibility for service providers. However, patching together existing cloud and network control mechanisms necessarily puts one over the above, e.g., OpenDaylight under an OpenStack controller. We designed and implemented a joint cloud and network resource virtualization and programming API. In this demonstration, we show that our abstraction is capable for flexible service chaining control over any technology domain

Scalable and energy-efficient optical tree-based greedy router

The IP prefix lookup as a core function of today's Internet routers is becoming a bottleneck due to ever increasing throughput demands. The increase in the size of the routing tables limits the scalability of current routing architecture. Greedy routing as an alternative to IP routing does not require lookups in order to find the next hop, and neither requires storing a forwarding table in every node. In this routing, network nodes are assigned 'coordinates' and the incoming packets are forwarded to the neighbours which are closer to the packets destinations. In this paper, a novel all-optical greedy router has been designed. In order to perform the greedy routing, each node is assigned an ID which determines the location of the node in the spanning tree of the network. The router is constructed through the interconnection of SOAs and directional couplers. The circuit provides high data rate and is more scalable and more energy-efficient than conventional IP routers