IP Fast Reroute Research Articles

Comparison of New Solutions in IP Fast Reroute

Currently, network requirements are placed on the efficiency and size of the networks. These conditions can be ensured by modern converged networks that integrate the functions of both data and telecommunication networks. Line or router failures have always been a part of transmission networks, which is no different from converged networks. As a result of outages, which can take from ms to tens of seconds, packets are lost. These outages cause degraded transmission quality, which is undesirable when transmitting real-time multimedia services (Voice over IP, video). To solve the mentioned problems, the IETF organization has developed IP Fast Reroute mechanisms to minimise the time to restore the connection after a line or node failure and, consequently, less packet loss. The article reviews and compares the latest IP Fast Reroute mechanisms deployed in the last three years. First, we have Optimistic Fast Rerouting, which calculates optimistic and fallback scenarios. The second is Post-processing Fast Reroute, which decomposes the network according to metrics such as load and route length. Third, Local Fast Reroute focused on low congestion and random access.

An Improvement of an IP Fast Reroute Method Using Multiple Routing Tables

<p>The demand for high Internet availability has increased. As a routing method to recover fast from a single network component (link or node) failure, a method using multiple routing tables has been proposed. In the method, when a component failure occurs, packets which are supposed to pass through the component in the failure free state are rerouted using a backup routing table (backup table: BT) which does not use the component. Thus, it is important to decrease the increased routing cost, and because the method uses multiple BTs, it is also important to decrease the numbers of entries in BTs. In this paper, we propose a new routing method to decrease the increased routing cost. In the conventional method, there are many components that do not fail but are not used for packet forwarding in a BT. In our proposed method, we use such components as much as possible to decrease the increased routing cost. About the decreasing of the numbers of entries in BTs, we simulate packet forwarding for every node-pair and find unnecessary entries which are not used in packet forwarding in any node-pair. Numerical examples show that our proposed method is superior to the conventional method. </p> <p> </p>

Enhanced Bit Repair IP Fast Reroute Mechanism for Rapid Network Recovery

The massive development of virtualized infrastructures, Internet of Things (IoT), and Wireless Sensor Network (WSN) in recent years has led to an increase in quality requirements for the management and reliability of underlay communication networks. Existing converged networks must therefore guarantee specific quantitative and qualitative parameters of different network communication services to meet customer requirements. However, the quality of the services operated is very negatively affected by an unpredictable failure of a communication link or a network node. In such situations, communication is typically interrupted for a period that is difficult to predict, and which can lead to significant financial losses and other negative effects. Internet Protocol Fast Reroute (IP FRR) technology was developed for these reasons. The paper presents the proposal of the new Enhanced Bit Repair (EB-REP) IP FRR mechanism, which offers significant improvements over its predecessor, the B-REP mechanism. The B-REP offers protection against a single failure and only for selected critical IP flows. The EB-REP provides advanced protection against multiple failures in a protected network domain and the protection can be provided for all network flows. The EB-REP calculates alternative paths in advance based on link metrics, but also allows the construction of alternative paths independently of them. The construction of alternative FRR paths uses a standardized tunneling approach via a unique field Bit-String. Thanks to these features, EB-REP is an advanced contribution to solving IP FRR-related problems, which enables the use of EB-REP in many network deployments, but especially in network solutions that require reliable data transmission.

P4-based implementation of BIER and BIER-FRR for scalable and resilient multicast

Bit Indexed Explicit Replication (BIER) is a novel IP multicast (IPMC) forwarding paradigm proposed by the IETF. It offers a transport layer for other IPMC traffic, keeps core routers unaware of IPMC groups, and utilizes a routing underlay, e.g., an IP network, for its forwarding decisions. With BIER, core networks do not require dynamic signaling and support a large number of IPMC groups with large churn rates. The contribution of this work is threefold. First, we propose a novel fast reroute (FRR) mechanism for BIER (BIER-FRR) so that IPMC traffic can be rerouted as soon as the routing underlay is able to carry traffic again after a failure. In particular, BIER-FRR enables BIER to profit from FRR mechanisms in the routing underlay. Second, we describe a prototype for BIER and BIER-FRR within an IP network with IP fast reroute (IP-FRR). It is based on the programmable data plane technology P4. Third, we propose a controller hierarchy with local controllers for local tasks, in particular to enable IP-FRR and BIER-FRR. The prototype demonstrates that BIER-FRR reduces the protection time for BIER traffic to the protection time for unicast traffic in the routing underlay.

A Fast Failure Recovery Scheme for Fibbing Networks

Fibbing is a network technology that can provide flexible routing in IP networks. In a Fibbing network, the network controller cleverly broadcasts link state advertisements (LSAs) of the open shortest path first (OSPF) protocol to generate fake nodes. These fake nodes enlarge the physical topology and turn the network into a virtual network. Although the routers still follow the shortest path routing in the virtual network, the flows are steered along the desired paths in the physical network. Even though a Fibbing network is capable of flexible routing, methods to achieve fast failure recovery have not been well studied. Conventionally, an IP network running the OSPF protocol takes a long time to converge after a failure occurs. The IETF proposed loop-free alternate (LFA) IP fast reroute technology to speed up failovers. However, we discovered that LFA technology is incompatible with Fibbing. The direct application of LFA technology in a Fibbing network will generate traffic loops. In this work, we propose a novel monitoring-cycle-based approach for fast failure recovery. By examining the liveness of the monitoring cycles, the system controller can promptly identify a failed link or a failed node and then perform traffic rerouting. Due to the properties of IP packet forwarding, a monitoring cycle in an IP network must be a simple cycle. We prove that any network that is both 2-vertex- and 3-edge-connected (2V3E) possesses a set of monitoring cycles that can be used to detect and identify any single link failure. In conjunction with the status pattern provided by the monitoring cycles, any single node failure can be detected by introducing an additional probe message. We propose an algorithm to obtain these monitoring cycles and design and implement a Fibbing controller for the network. To evaluate the performance of the proposed approach, we construct a physical testbed and an emulation network. The experimental results show that the proposed system works stably and can achieve a fast failover within a short period of time.

The new Multicast Repair (M‐REP) IP fast reroute mechanism

SummaryThe network convergence time may take hundreds of milliseconds or more. Since this repair performance may be unsatisfactory, IP fast reroute (IPFRR) approaches have been developed to decrease the network convergence time and minimize traffic loss. These IPFRR mechanisms are usually based on the proactive precomputation of a backup path before a failure occurs. Once a failure is detected, the router running IPFRR will immediately use this backup path in response to the failure, rather than computing a replacement path only after a failure has occurred. The computation of an alternative path in many IPFRR mechanisms requires that the computing node (router) knows the exact network topology. In this paper, we present a new IPFRR mechanism called the multicast repair (M‐REP) IPFRR mechanism, which provides an advanced fast reroute technique for Internet service providers‘ (ISP‘s) core networks. The M‐REP IPFRR mechanism is based on IP multicast and utilizes Protocol Independent Multicast – Dense Mode (PIM‐DM) with the modification of an internal reverse path forwarding (RPF) check. The M‐REP IPFRR mechanism does not depend on any particular routing protocol type (distance‐vector or link‐state) and requires less system resources because of its precomputation‐less character but still provides immediate reaction to failure.

Conflict-free rerouting scheme through flow splitting for virtual networks using switches

The weaknesses of the Internet led to the creation of a new network paradigm – network virtualization. Virtualization is a very successful technique for sharing and reusing resources, which results in higher efficiency. Despite its advantages, including flexibility in network architecture, virtualization imposes many challenges, such as physical resource allocation to virtual devices. An efficient allocation strategy for these resources can ensure good Quality of Service (QoS) in virtual networks, whether in node or link failure events. This paper presents a conflict-free rerouting scheme with efficient additional capacity usage for link and node failure resilience in a virtual network using switches. Combining an IP Fast Rerouting approach and flow-splitting strategy, this scheme provides short reaction time, stable performance and low complexity because the rerouting calculation and configuration are performed in advance. We show that rerouting by traffic splitting based on the entering arc and destination is sufficient to address all link-failure situations in the network, assuming that the network is two-link connected. After modelling the dimensioning problem as an Integer Linear Programme, we demonstrate through practical implementation of our rerouting scheme on different networks that the scheme can substantially minimize the additional capacity draw on the substrate network. A solution using multiple virtual planes is also provided to solve several conflict problems in the case of simultaneous multiple link failures.

Research on IP fast Recovery based on Multi-topology Routing

In order to reduce the need for rerouting of IP fast rerouting (rerouting the number of hops added by the packet). Based on the basic principle of multi-route backup configuration, this paper proposes a new backup topology generation method based on the ordering of important nodes in complex networks. The main idea is to sort the nodes in the network topology by using the K-Shell decomposition algorithm and introduce the contribution between the nodes, and then select the key nodes for the generation of the backup topology. The experimental results show that the proposed algorithm can effectively reduce the number of rerouting hops and verify the feasibility and effectiveness of the algorithm.

Loop-Free Convergence With Unordered Updates

This paper studies the feasibility of minimizing convergence delay and forwarding disruption without carrying any additional bits in the IP header, to provide high availability despite link failures in traditional IP networks. Previously proposed mechanisms achieve two of these three objectives by trading off the other objective. For instance, the ordered forwarding information base updates approach may prolong the convergence delay, whereas the SafeGuard scheme requires carrying the path cost in the IP header. As a better alternative, we propose a scheme called fast convergence with fast reroute (FCFR), which combines the features of IP fast rerouting and interface-specific forwarding. We show that FCFR can achieve minimal convergence delay, while ensuring loop-free delivery during convergence, after a single non-partitioning failure in an IP network, without altering the IP header format, making it amenable for immediate deployment.

IP Fast Rerouting for Multi-Link Failures

IP fast reroute methods are used to recover packets in the data plane upon link failures. Previous work provided methods that guarantee failure recovery from at most two-link failures. We develop an IP fast reroute method that employs rooted arc-disjoint spanning trees to guarantee recovery from up to $(k-1)$ link failures in a $k$ -edge-connected network. As arc-disjoint spanning trees may be constructed in sub-quadratic time in the size of the network, our approach offers excellent scalability. Through experimental results, we show that employing arc-disjoint spanning trees to recover from multiple failures reduces path stretch in comparison with previously known techniques.

Adaptive Load Balancing Based on IP Fast Reroute to Avoid Congestion Hot-spots

Several load balancing techniques for IP routing scheme have appeared in the literature. However, they require optimization process to compute optimal paths to meet traffic demand so that it requires a mechanism to measure traffic demand and to share them among all routes in order to follow dynamics of traffic. It naturally results in communication overhead and losing sensitivity to follow traffic dynamics. In this paper, we investigate a load balancing mechanism from another approach, i.e., based on IP fast reroute mechanisms. The main idea is simply to forward packets into detour paths supplied by IP fast reroute mechanisms only when packets meet congestion. This strategy enables us to use vacant resources adaptively as soon as they are required to avoid and dissolve the congestion. Through traffic simulation we show that IP fast reroute based load balancing mechanisms improve the capacity of networks.

Reactive Load Balancing During Failure State in IP Fast Reroute Schemes

Reactive Load Balancing During Failure State in IP Fast Reroute Schemes

Optimization methods for improving IP-level fast protection for local shared risk groups with Loop-Free Alternates

Lately, demand for fast failure recovery in IP networks has become compelling. The Loop-Free Alternates (LFA) specification is a simple IP Fast ReRoute (IPFRR) scheme proposed by the IETF that does not require profound changes to the network infrastructure before deployment. However, this simplicity comes at a severe price, because LFA does not provide complete protection for all possible failure cases in a general topology. This is even more so if network components are prone to fail jointly. In this paper, we study an important network optimization problem arising in this context, the so called LFA graph extension problem, which asks for augmenting the topology with new links in an attempt to improve the LFA failure case coverage. Unfortunately, this problem is NP-complete. The main contributions of the paper are a novel extension of the bipartite graph model for the LFA graph extension problem to the multiple-failure case using the model of Shared Risk Groups, and a suite of accompanying heuristics to obtain approximate solutions. We also compare the performance of the algorithms in extensive numerical studies and we conclude that the optimum can be approximated well in most cases relevant to practice.

Self-configuring loop-free alternates with high link failure coverage

A change in network topology triggers the re-convergence process of routing protocols. The re-convergence time of current routing protocols (e.g. OSPF) is constrained by the possibility of having transient loops due to the independent calculation of shortest paths between routers affected by a network failure. Several IP Fast-ReRoute (IPFRR) schemes have been developed to pro-actively calculate and install alternate forwarding entries almost instantaneously once a topology update message is received, without causing temporary micro-loops. The IPFRR scheme which has been used most extensively so far makes use of Loop-Free Alternates (LFA). While these are easy to configure, LFAs still require manual configuration, and the resulting ratio of covered link failures is only about 60 to 70 percent. This paper presents a logical extension of the Loop-Free Alternate concept, proposes a self-configuring scheme to populate the corresponding alternate entries, and evaluates the performance of the scheme with respect to coverage, configuration time and path length in a simulation environment.

Autonomous IP Fast Rerouting with Compressed Backup Flow Entries Using OpenFlow

Autonomous IP Fast Rerouting with Compressed Backup Flow Entries Using OpenFlow

A routing scheme distributing traffic using primary and backup ports of IP fast reroute

A routing scheme distributing traffic using primary and backup ports of IP fast reroute

A New Backup Topology Design Method for Congestion Avoidance in IP Fast Reroute

We present a backup topology design method to avoid congestion in IP Fast Reroute. IP Fast Reroute techniques prepare backup topologies used to determine backup routes after a network failure. However, using more backup topologies consumes a lot of network resources. Reducing the nu mber o f backup topologies is a problem, as some lin ks becomes overloaded. In this paper, we present a backup topology design method that splits the traffic on high load links to other links by considering network conditions, such as the traffic matrix or topology. The main idea of our method is the introduction of a concept called a Special Node, which is a node with a h igher node degree, in the backup topology. We quantitatively illustrate the effectiveness of our method in terms of maximu m lin k load reduction. The results show that, with the same nu mber of backup topologies as the conventional method, our method can reduce congestion by 75%. It is effective for various topology models and not dependent to the network size. In this paper, we demonstrate that by selecting about 20% of the nodes as Special Nodes is very effect ive, part icularly in large networks selecting Special Nodes whilst considering node position gives maximu m effect. In this paper, we present that using our approach of selecting Special Nodes in the backup topology and then maximize the number of available links to the Special Nodes we can avoid congestion in IP Fast Reroute.

Minimum Protection Cost Tree: A tunnel-based IP Fast Reroute Scheme

Diverse delay-sensitive realtime applications, e.g., Voice over IP, are emerging in the Internet and bringing a rigorous requirement on the transmission delay. Therefore, several IP Fast Reroute (IPFRR) schemes have been proposed. However, these schemes are all either too computationally expensive or unsatisfactory in protection coverage. In this paper, we propose Minimum Protection Cost Tree (MPCT), a tunnel-based IP Fast Reroute Scheme. First, MPCT provides 100% single-node protection coverage with direct forwarding (DF). Second, the computational complexity of MPCT is less than one full shortest path first (SPF) calculation. Third, by simulation with the data from China Education and Research Network (CERNET), Rocketfuel and BRITE, we show that even without DF, MPCT can provide more than 99% protection coverage. Besides, the protection path stretch ratios in real topologies are between 10% and 20%, which is acceptable compared with the corresponding achievement of reducing the algorithm complexity. We believe that our scheme MPCT moves a big step towards practical deployment.

Loop-Free IP Fast Rerouting Considering Double-Link Failures

Loop-Free IP Fast Rerouting Considering Double-Link Failures

Selecting shorter alternate paths for tunnel-based IP Fast ReRoute in linear time

IP Fast ReRoute (IPFRR) has received increasing attention as a means to effectively shorten traffic disruption under failures. A major approach to implementing IPFRR is to pre-calculate backup paths for nodes and links. However, it may not be easy to deploy such an approach in practice due to the tremendous computational overhead. Thus, a light-weight IPFRR scheme is desired to effectively provide cost-efficient routing protection. In this paper, we propose a Fast Tunnel Selection (FTS) approach to achieve tunnel-based IPFRR. FTS approach can find an effective tunnel endpoint before complete computation of entire SPT and thus effectively reduce computation overhead. Specially, we propose two FTS algorithms to provide protection for networks with symmetric and asymmetric link weights. We simulate FTS with topologies of different sizes. The results show that FTS approach reduces more than 89% computation overhead compared to the existing approaches, and achieves more than 99% average link protection rate and more than 90% average node protection rate. Moreover, FTS approach achieves less than 15% path stretch, which is better than the existing approaches.