Probe-based end-to-end overload control for networks of SIP servers

The Session Initiation Protocol (SIP) has been adopted by the IETF as the control protocol for creating, modifying and terminating multimedia sessions. Overload occurs in SIP networks when SIP servers have insufficient resources to handle received messages. Under overload, SIP networks may suffer from congestion collapse due to current ineffective SIP overload control mechanisms. This paper introduces a probe-based end-to-end overload control (PEOC) mechanism, which is deployed at the edge servers of SIP networks and is easy to implement. By probing the SIP network with SIP messages, PEOC estimates the network load and controls the traffic admitted to the network according to the estimated load. Theoretic analysis and extensive simulations verify that PEOC can keep high throughput for SIP networks even when the offered load exceeds the capacity of the network. Besides, it can respond quickly to the sudden variations of the offered load and achieve good fairness

A distributed end-to-end overload control mechanism for networks of SIP servers.

The Session Initiation Protocol (SIP) is an application-layer control protocol standardized by the IETF for creating, modifying and terminating multimedia sessions. With the increasing use of SIP in large deployments, the current SIP design cannot handle overload effectively, which may cause SIP networks to suffer from congestion collapse under heavy offered load. This paper introduces a distributed end-to-end overload control (DEOC) mechanism, which is deployed at the edge servers of SIP networks and is easy to implement. By applying overload control closest to the source of traf?c, DEOC can keep high throughput for SIP networks even when the offered load exceeds the capacity of the network. Besides, it responds quickly to the sudden variations of the offered load and achieves good fairness. Theoretic analysis and extensive simulations verify that DEOC is effective in controlling overload of SIP networks

Accurately Identifying New QoS Violation Driven by High-Distributed Low-Rate Denial of Service Attacks Based on Multiple Observed Features

We propose using multiple observed features of network traffic to identify new high-distributed low-rate quality of services (QoS) violation so that detection accuracy may be further improved. For the multiple observed features, we choose F feature in TCP packet header as a microscopic feature and, P feature and D feature of network traffic as macroscopic features. Based on these features, we establish multistream fused hidden Markov model (MF-HMM) to detect stealthy low-rate denial of service (LDoS) attacks hidden in legitimate network background traffic. In addition, the threshold value is dynamically adjusted by using Kaufman algorithm. Our experiments show that the additive effect of combining multiple features effectively reduces the false-positive rate. The average detection rate of MF-HMM results in a significant 23.39% and 44.64% improvement over typical power spectrum density (PSD) algorithm and nonparametric cumulative sum (CUSUM) algorithm

Гистерезисное управление сигнальной нагрузкой в сети SIP-серверов

This review deals with the research of load control mechanisms in signaling networks that use three types of thresholds for congestion control. The main objective of this paper is toanalyze the congestion control mechanisms and mathematical models for SIP-servers. Thestudy is based on hysteresial techniques of flow control, which originally was developed forSignaling System 7. We propose general methods for describing hysteresis signaling flow control techniques. We study the current situation and problems of SIP built-in overloadcontrol mechanism, proposed by IETF. Our approaches to mathematical models constructionin the form of queuing systems with hysteresis control are presented.В статье, являющейся по сути обзором, исследуются механизмы управления нагрузкой в сетях сигнализации, которые используют три типа порогов для контроля перегрузок. Целью обзора является анализ механизмов и моделей контроля перегрузок SIP-серверов. В основе исследований лежит гистерезисное управление нагрузкой, которое исходно было разработано для общеканальной системы сигнализации №7. Разработаны унифицированные методы описания процедур гистерезисного управления сигнальной нагрузкой. Исследовано современное состояние и проблемы базового механизма контроля перегрузок SIP-серверов, предложенного комитетом IETF. Изложены подходы к построению математических моделей SIP-серверов в виде систем массового обслуживания с гистерезисным управлением

Ylikuorman hallinta Diameter-protokollassa liikkuvuuden hallintaa varten

The purpose of this thesis is to develop an overload control solution for Diameter protocol traffic between the MME and HSS in the EPC. The solution is based on using overload information from HSSs and throttling the traffic as needed based on the information. Diameter message prioritization is used to enable ongoing trans- actions to succeed and thus reduce the overload. The performance of the solution is measured with four indicators measuring various aspects of the system's performance. Performance measurements are done via simulations and their results show a clear improvement in system performance when the solution is enabled.Työn tarkoituksena on kehittää ylikuormanhallintaratkaisu neljännen sukupolven matkapuhelinverkkojen ytimen EPC:n MME- ja HSS-verkkoelementtien väliselle Diameter-protokollan yli tapahtuvalle liikenteelle. Hallintaratkaisu perustuu HSS- elementin MME-elementille välittämään tietoon ylikuormasta ja siihen perustuvaan MME-elementin tarpeen vaatiessa tekemään liikenteen rajoittamiseen. Käynnissä olevien transaktioiden lähettämisen onnistuminen varmistetaan käyttämällä Diameter-sanomien priorisointia, mikä vähentää ylikuormaa, kun niitä ei tarvitse lähettää uudestaan. Ratkaisun suorituskykyä mittaamaan on kehitetty neljä eri osa-alueiden suorituskykyä kuvaavaa mittaria. Varsinainen suorituskyvyn mittaus on tehty toteuttamalla ratkaisua simuloiva sovellus ja simulaatioiden tulokset osoittavat järjestelmän suorituskyvyn selkeästi parantuneen ratkaisun ollessa käytössä

SIGNALING OVERLOAD CONTROL FORWIRELESS CELLULAR NETWORKS

As the worldwide market of cellular phone increases, many subscribers have come to rely on cellular phone services. In catastrophes or mass call in situations, the load can be greater than what the cellular network can support, and the entire network may become completely non-functional. This raises serious concerns on the survivability of wireless cellular networks in order to provide necessary services such as 911 calls in those circumstances. In high load cases, overload control must be deployed to reserve network resource for emergency traffic and maintenance services. Over the past several years, many catastrophes have revealed the deficiencies of the existing overload control mechanisms in cellular networks. Improvement to the existing overload controls are needed in order to cope with unexpected situations. A key to the survivability of wireless cellular networks lies in the signaling services from database servers that support a call connection throughout its duration (e.g., for monitoring users' locations and supplying authentication codes for secure communications), this dissertation focuses on the overload control at the database servers.As loss of different signaling services impacts a user's perception differently, the overload controlis proposed to provide differentiation and guaranteed classes of signaling services. Specifically, multi-class token rate controls are proposed due to theirs flexibility in various network configurations and advantages over other controls such as, percentage blocking and call gapping. The concept of adaptive control decision is used so that the proposed controls react quickly to changes in the load. A simulation based performance evaluation of the proposed control is conducted and compared with existing controls. It is shown that the proposed controls outperform the existing multi-class token based controls due to various reasons. First, the proposed controls use adaptive resourcesharing that guarantees a lower bound, where the percentage of resource sharing among classesis adaptively set. The existing token rate controls either distribute resource among classes usingstatic ratios or completely share resources among classes. Although using static ratios guarantees the quality of service within each class, it lowers the total utilization of the server. Whereas,allowing a complete resource sharing among classes may cause large load fluctuations in each class. Second, the proposed controls use the novel concept of integrating information on the availability of the radio resources into the control decision, allowing servers to save theirs resources from serving signaling that later on might be dropped due to unavailable radio resources