Abstract—Software attacks. In this paper we are making

Abstract—Software De?ned Network (SDN) is an emerging technology which is comprised of multiple kinds of network technologies, inorder to make the network agile and more user friendly along with improvement in storage infrastructure and in security. Some security threats are evolved along with SDN also. Distributed Denial of Service(DDoS) attack is one of the major attacks in SDN architecture. DDoS attack is cyber attack in which a group of attackers with different IP addresses ?oods the fake requests and massages to victim to make the resource exhaustion in victim and results in Denial of Service in victim. This paper is a study of different methods used by the attackers to create denial of service in SDN architecture. Also this paper includes major defense methodologies to avoid DDoS attacks. In this paper we are making a comparative study between various defense schemes used in DDoS attack in SDN architecture. Keywords—DDoS, SDN, Defense Schemes.I. INTRODUCTION SoftwareDe?nedNetwork(SDN)isanemergingtechnology. In SDN, it takes the advantage of various network architecture, but SDN differs from other architectures such as wireless networks, Mobile networks, campus network, etc. in the way that control plane and data plane are decoupled in manner. more over in SDN, the network intelligence and state are logically centralized. Being an emerging technology SDN faces several traditional security threats and some threats that have emerged along with SDN, discussed in 1.Distributed Denial of Service (DDoS) attack is one of the main attack that can occur in SDN. This makes a challenge to industries to select SDN as their key network2. DDoS attackers selects new methods to attack traditional network, since in traditional networks the administrators choose various defense methods to tackle DDoS attacks. Since the SDN in an emerging technology, it has the overhead of affecting DDoS attack easily. The methods used to prevent attack in traditional network such as thresholds and predetermined, prede?ned data will not work in SDN, but attacks in SDN can identi?ed by the methods such as machine learning techniques, future predictions, etc. In order to use these kind of technologies, we need to have a brief idea about various DDoS attack types in SDN.II. DDOS ATTACKS IN SDN DDoS attack is cyber attack in which a group of attackers with different IP addresses ?oods the fake requests and massages to victim to make the resource exhaustion in victimand results in Denial of Service in victim. DDoS attacks in SDN architecture is a updated version of conventional attack methods. The attack exploits the properties of traditional DDoS attack methods such as volumetric attack , protocol exploitation , resource depletion , etc 2. We can classify the DDoS attack in SDN as data plane attack and control plane attack3. Data plane DDoS attackers exploits the resource, protocol to create DDoS in victim networks 4. There are mainly 5 different methods for Data Plane DDoS attacks 3.A. ICMP ping ?ood attack ICMP ping ?ood attack is a protocol exploitation attack. The attack is carried out in such a way that, attacker ?oods ICMP echo messages to victim, which results in resource exhaustion and disturbs resource utilization of other applications4. The network will be restored immediately after the attack3. Fig 1 shows a ICMP ping ?ood attack, echo request is sent by attacker and victim sends replies to spoofed IPs and thereby gets rejected .Fig. 1. ICMP/Ping ?ood attack methodB. Smurf attack Smurf attack is a updated version of ICMP ping ?ood attack. Smurf attack is a volumetric, re?ection attack in such a way that victim overwhelms with unwanted responses3. Unlike ICMP ping ?ood attack attacker ?oods ICMP echo request to various machine with victim IP .victim will be over?owed with huge number of ICMP replies and results in over?owing of resources like buffers of victim.?g 2 shows how a smurf attack