Taesang Choi

Wise : traffic engineering server for a large-scale MPLS-based IP network

As the Internet evolves quickly from a best-effort network to a critical communications infrastructure that requires a higher level of controllability and guarantee of service quality, and the delivery of such communications services becomes even more competitive, large-scale NSPs or ISPs have to focus more on the performance and efficient resource utilization of their networks. This situation naturally leads the providers to seek possible solutions from traffic engineering (TE) methodology. We propose a TE server for a large-scale MPLS-based IP network which addresses TE requirements, such as the measurement, characterization, modeling and control of Internet traffic.

Design and implementation of an information model for integrated configuration and performance management of MPLS-TE/VPN/QoS

Multi protocol label switching (MPLS) is generally considered a mature technology. Many Internet service providers (ISP) and telecommunication carriers have deployed it or are considering deploying it. An easy-to-use integrated management solution is requested by these ISP. To realize a truly integrated management solution, a combined management information model is essential. In this paper, we propose an information model for integrated configuration and performance management of MPLS-traffic engineering (MPLS-TE)/VPN/QoS.

X-CLI: CLI-based management architecture using XML

As Internet technology becomes more complex, the policy information for managing the Internet grows beyond the capability of a simple protocol like SNMP. IETF suggested COPS (common open policy service) as an alternative, but it has not been widely accepted. For that reason, many administrators have developed network management systems which control network devices using CLI (command line interface), but systems based on CLI have a maintenance problem: when the syntax of CLI changes, the implementation of the system must be modified. We suggest X-CLI (XML wrapper API for CLI) as a solution for this problem, and describe its design principles.

Policy management for BGP routing convergence using inter-AS relationship

The Internet routing instability, or the rapid fluctuation of network reachability information, is an important problem currently facing the Internet engineering community. High levels of network instability can lead to packet loss, increased network latency, and delayed routing convergence. At the extreme, high levels of routing instability can lead to the loss of internal connectivity in wide-area networks. In this paper, we investigate the variation of domain degree and domain count of the inter-domain network over time by using linear regression model in order to analyze the topology variation of inter-domain network. We also propose an efficient policy management model to reduce the instability in the inter-domain routing system. The proposed model can be used to identify whether a routing policy is adequate to reduce convergence time that is required to return to a normal state when BGP routing instability happens. Experimental analysis shows that the proposed model can be used to set up routing policy in domains for the purpose of minimizing the effects and the propagation of BGP routing instability.

Forensic analysis of autonomous system reachability

Security incidents have an adverse impact not only on end systems, but also on Internet routing, resulting in many out-of-reach prefixes. Previous work has looked at performance degradation in the data plane in terms of delay and loss. Also it has been reported that the number of routing updates increased significantly, which could be a reflection of increased routing instability in the control domain. In this paper, we perform a detailed forensic analysis of routing instability during known security incidents and present useful metrics in assessing damage in AS reachability. Any change in AS reachability is a direct indication of whether the AS had fallen victim to the security incident or not.We choose the Slammer worm attack in January, 2003, as a security incident for closer examination. For our forensic analysis, we use BGP routing data from RouteViews and RIPE. As a way to quantify AS reachability, we propose the following metrics: the prefix count and the address count. The number of unique prefixes in routing tables during the attack fluctuates greatly, but it does not represent the real scope of damage. We define the address count as the cardinality of the set of IP addresses an AS is responsible for either as an origin or transit AS, and observe how address counts changed over time. These two metrics together draw an accurate picture of how reachability to or through the AS had been affected. Though our analysis was done off-line, our methodology can be applied on-line and used in quick real-time assessment of AS reachability.

Design and Implementation of Traffic Engineering Server for a Large-Scale MPLS-Based IP Network

As the Internet is quickly evolving from best-effort networks to a very critical communications infrastructure that requires higher quality Internet services and the delivery of such communications services become competitive, large-scale NSPs or ISPs have to concern much more on the performance and efficient resource usages of their networks. This situation naturally leads the providers to seek a possible solution from traffic engineering (TE) methodologies. In this paper, we propose a TE server solution for a large-scale MPLS-based IP autonomous system, which addresses these TE requirements such as the measurement, characterization, modeling and control of Internet traffic.

An integrated service and network management system for MPLS traffic engineering and VPN services

MPLS technology has recently been widely adopted, not only in large-scale IP backbones, but in metro and enterprise networks as well. Among the merits of MPLS, effective and efficient support of TE (traffic engineering) and VPN (virtual private network) services is the most influential factor that has facilitated the diffusion of the technology. However, although MPLS itself has become a currently operational technology, issues regarding the management of various services that are built on top of individually operating MPLS capable network elements have not been well identified or solved. These service level management issues arise, not only under heterogeneous conditions, but even when the target network is homogeneously composed. The paper discusses the requirements and architectural aspects of an integrated service management system for MPLS TE and VPN services. The discussion encompasses fault and performance management issues and information models which should be flexible to support newer services that can be rendered by merging TE, VPN, and QoS technologies. We also examine performance, fault tolerance, and scalability issues that cannot be neglected when such systems are deployed in a real-world environment.

Design and Implementation of Information Model for Configuration and Performance Management of MPLS-TE/VPN/QoS

Multi Protocol Label Switching (MPLS) is generally considered a mature technology. Many Internet Service Providers (ISPs) and telecommunication carriers have deployed it or are considering deploying it.An easy-to-use integrated management solution is requested by these ISPs. To realize truly integrated management solution, a combined management information model is essential. In this paper, we propose an information model for integrated configuration and performance management of MPLS-Traffic Engineering (MPLS-TE)/VPN/QoS.