Priority Queuing Technique Promoting Deadline Sensitive Data Transfers in Router based Heterogeneous Networks

Transcription

1 Priority Queuig Techique Promotig Deadlie Sesitive Data Trasfers i Router based Heterogeeous Networks Jyothish K Joh 1 ad R.V.Siva Bala 2 1 Research Scholar at Noorul Islam Uiversity, Tamil Nadu, Idia. 1 Assistat Professor at Federal Istitute of Sciece ad Techology, Kerala, Idia. 2 Associate Professor i MCA, Noorul Islam Uiversity, Tamiladu, Idia. 1 Orcid: , 2 Orcid: Abstract A heterogeeous etwork coects various operatig systems ad differet protocols. Due to the versatile techology ad eormously large umber of odes, the data traffic i iteret is upredictable ad keeps icreasig mootoously. This leads to cogestio which maily overburdes the routers sice the router is resposible for directig the traffic i the required etwork directio. Real-time data trasfers which have deadlies o various Quality of Service (QOS) parameters may suffer from severe problems of throughput ad delay while gettig trasferred through iteret. This ca be overcome either by a schedulig mechaism or by a droppig policy which help the real-time data trasfers achieve their QOS requiremets without keepig a bias agaist o-real-time data flows. I this work, we propose a cogestio avoidace techique which works o the basis of priority queuig. Whe cogestio is sesed, the deadlie sesitive data is serviced before the lower priority data. Thus, the etwork ca be maitaied stable without collapse ad data trasmissio ca also be achieved to a satisfactory level. Keywords: AAQM, Quality of Service, real-time data trasfers, NCQ, utilizatio factor INTRODUCTION Durig data trasmissio, cogestio occurs whe the icomig packets rates are very high whe compared to the shared resources like queue buffer withi the router ad outgoig badwidth. Whe cogestio is experieced i the etwork, delay is experieced by umerous data packets ad several packets get dropped as the queue starts overflowig. Excessive cogestio i the etwork leads to throughput degradatio ad icreased rate of packet loss. Network efficiecy ad reliability also reduces due to cogestio. Sometimes, due to excessive cogestio, the overall performace of the etwork fails ad there will be o data delivery [1]. The geeral router policies desiged for fair badwidth sharig i iteret majorly cocetrates i restrictig the o-resposive category. No-resposive traffic flows are those which do ot reduce the trasmissio rates eve whe a cogestio otificatio is received. But this will become a severe blow for the real-time data trasfers which cotribute oly small rates. There should be a policy by which the schedulig or droppig module should idetify realtime flows from all other traffic ad promote them. The extet of favour may be proportioal to the data rate they cotribute to the iteret. Those flows cotributig less data rates should be able to achieve their QOS deadlies. The Active queue maagemet schemes (AQM) like RED ad its variats helps to check ad react to the cogestio proe situatio but they lack service differetiatio capability to ifer whether the traffic is deadlie sesitive or ot. Therefore a queuig policy implemetig easy service differetiatio ad accurate prioritizatio help to build a stable trasmissio rate eve at the time of cogestio. RELATED WORK Itegrated service [2] & differetiated service [3] are applicatio level architectures for esurig QOS for ay type of traffic. The disadvatages of QOS architectures are additioal protocol overhead, poor scalability ad high ifrastructural eeds. Radom early detectio gateway for cogestio avoidace [4] was proposed i 1993 by Floyd ad Jacobso ad is ow recommeded for deploymet i the Iteret. RED allows a router to drop packets before its queue becomes saturated. Therefore cogestio resposive flows will back-off early resultig i shorter average queue legths which is good for iteractive applicatios. Aother advatage is packet drops will ot occur i bursts. RED achieves this by droppig packets with a certai probability depedig o the average queue legth. RED does ot categorize the flows ito realtime ad o-real- time, so RED policy does ot explicitly promote real-time data trasfers. The variats of RED, RIO (RED IN/OUT) [5] & Weighted RED (WRED) [6] are other examples of active queue maagemet schemes. The droppig policy is based o priority levels which are idicated withi packets ad i a cogested sceario, lower priority packets are dropped.rio ad WRED eed packets to be marked with priority levels. D.Li ad R. Morris [7] proposes a separate queue 4899

2 maagemet scheme called FRED (Flow Radom early Detectio, modified versio of RED) suitable for fragile ad adaptive flows. FRED maitais better fairess by admittig the equal share of flows. Hece it cotrols misbehavig flows from cosumig more badwidth. But the policy is also ot focussed towards promotig real-time data trasfers. Floyd ad K. Fall [8] propose a router policy to restrict the uresposive flows that does ot reduce the sedig rate eve whe packets are dropped. Such flows are termed as o-tcp friedly flows ad such flows are idetified from the drop history of RED. R. Mahaja ad S. Floyd [9] propose a mechaism to cotrol the droppig of resposive flows. The techique have two parts 1) Idetifyig the resposive flows 2) Mechaism to prevet the droppig for resposive flows. Idetifyig the flows is performed by radom samplig from the RED drop history. W. Feg ad et al. [10] proposes aother Active Queue Maagemet Algorithm, BLUE. A problem with queue maagemet (like RED) algorithms is highlighted i the paper as they use queue legths as the idicator of the severity of cogestio. Istead BLUE uses packet loss ad lik idle evets to idetify cogestio. R. Pa, B. Prabhakar, ad K. Psouis [11] propose a stateless active queue maagemet scheme-choke which deals with a alterate queue maagemet scheme ispired from RED. The queue for icomig packet is FIFO which is havig a RED like miimum ad maximum thresholds. But RED tries to maitai fairess oly after the queue legth become greater tha miimum threshold ad by this time misbehavig flows may have occupied the queue. Therefore fairess i RED is oly grated after queue legth is greater tha miimum threshold. CHOKe scheme oly differs i policy betwee miimum threshold ad maximum threshold whe compared to RED. CHOKe algorithm try to brig better fairess. It assumes that the statistics of misbehavig flows are preset i the occupacy before attaiig miimum threshold. L. Mamatas ad V. Tsaoussidis [12] propose a ew service differetiatio policy for real-time traffic. They suggest a ew schedulig policy for o-cogestive packets. Nocogestive packets are packets that do ot cause cogestio i etwork (real-time packets).they are aalysed by their small packet sizes. The router captures the size of the packet ad lears whether it is real time traffic, if so it is serviced faster. The limit of favour is cotrolled by a cofigurable threshold. They experimets the impact of o-cogestive queuig, NCQ [14] for sesor traffic. The authors propose LIBS [13] (Less Impact Better Service) philosophy. The packets ca be classified ito cogestive ad o-cogestive based o packet sizes. Packet sizes serves as a easier idetificatio for realtime data trasfers i iteret. Rahim Rahmai et al [15] have proposed a Adaptive AQM (AAQM) scheme. A specific method has bee proposed based o the Markov Modulated Poisso Process (MPP) to cofie the burstiess of the traffic ad also the buffer occupacy. This scheme maages to keep the packet arrival rate ad the packet departure rate very close. Kag Mi Lee et al [16] have preseted the LQ-Servo cotroller for AQM (Active Queue Maagemet) routers. The cotroller i this proposed work is developed by usig the covetioal servo techique which works o the basis of the Liear Quadratic Approach ad the addig a state variable ito the feed forward loop. The cotroller structure icludes a stadard optimal feedback regulator ad also a feed forward cotroller. This is capable of improvig the resource utilizatio ad the miimizig the eedless reservatio of the router memory like RAM (Radom Access Memory) or SMA (Shared Memory Area). Tushar Raheja et al [17] have preseted a uiterrupted sigle-lae traffic based o the queuig aalysis. The Jackso Queuig etwork aalysis is utilized to attai the traffic flow desity diagram. To determie the result of the o homogeous traffic, the simpler aalytical models are utilized. The paper, Survey o Router Policies Providig Fairess ad Service Differetiatio Favorig Real-Time Data Trasfers i Iteret [18] provides a detailed study ad compariso of all the major router policies ad service differetiatio architectures. PROPOSED PRIORITY QUEUING TECHNIQUE FOR CONGESTION AVOIDANCE Overview I this work, we propose to desig a deadlie based priority queuig techique for cogestio avoidace i router based heterogeeous etworks. Durig packet arrival, the packet size is checked. The the utilizatio factor (U) which is the ratio of umber of packet arrivals per departures is calculated [15]. The queue is divided ito two sub-queues: high priority ad low priority. If there is cogestio, the packet droppig probability is icreased for lower priority queues ad decreased for high priority queues. By this way both cogestive ad o cogestive packets are served without affectig the quality of service ad deadlie costraits. Packet Arrival Evet Adaptive AQM (AAQM) utilizes the packet arrival evet whe a packet arrivig at oe of access router icomig iterfaces is supposed to be trasmitted to the outgoig iterface. The packet arrival evet is described i the algorithm give bellow Q Q max Data Packet curret queue legth maximum queue legth 4900

3 P R um packet markig probability radom umber C arrival couter coutig the umber of packets arrived at the queue 1. Whe arrives at a queue, its Q value is compared with Q max. 2. If Q > Q max, the the packet is dropped. 3. If Q < Q max, the the packet is equeued ad a R um is geerated usig a radom umber geerator. 4. If R um < P, the the packet is marked. 5. If R um > P, the the packet is discarded. 6. The C arrival is icremeted by oe. Packet Departure Evet Whe a packet which was equeued at the router is trasmitted over the outgoig lik, the this process is called as the packet departure evet. The packet departure evet is described i algorithm bellow Data Packet C departure couter coutig the umber of packets departed from the queue 1. Durig the packet departure evet, is iitially dequeued from the queue at the router. 2. The the C departure value durig the last pre defied time iterval is icremeted by oe. Utilizatio Factor The utilizatio factor (U) is the ratio of the umber of packet arrived per departure. U = C arrival value C departure value Cogestio Cotrol based o Packet Priority No Cogestive Queuig (NCQ)[12] is icorporated ito routers to differetiate services accordig the impact of each traffic class o delay. Whe there is a class with smaller packets ad sedig rate receives better service tha oe with large packets or high sedig rate. To avoid reachig a state where the trasmissio of the small packets creates a delay i the trasmissio of the log packets, a threshold level is defied i this techique. The favoured o-cogestive traffic caot exceed a predetermied threshold, which represets the upper limit of permitted prioritized service. The threshold typically reflects a service percetage for prioritizatio. However, this percetage correspods to the umber of packets; ot the occupied buffer space. After the determiatio of the utilizatio factor i the etwork, the cogestio ca be hadled by dividig the data packets ito high priority data ad lower priority data. Therefore durig cogestio, the higher priority data will be trasmitted first ad the the lower priority data is cosidered for trasmissio. This mechaism is described i algorithm bellow. Thresh size Threshold value for the size of the data packet U packet size P Utilizatio Factor icomig data packet size of the icomig data packet Packet Droppig Probability 1. Iitially a Thresh size value is defied. 2. Durig cogestio, the size of is determied. 3. The the packet size is compared with the predefied Thresh size. 4. If packet size < Thresh size ad U 1, the the data packet is moved ito the high priority sub queue. 5. If packet size > Thresh size ad U<=1, the the data packet is moved ito the high priority sub queue. 6. If packet size > Thresh size ad U > 1, the the data packet is moved ito the lower priority sub queue. 7. If packet size < Thresh size ad U > 1, the the data packet is moved ito the higher priority sub queue. 8. After the data packet categorizatio, the data packet i the higher priority queue is trasmitted ad the lower priority queue is equeued. 9. Whe there is a eed to drop packet i order to stabilize the etwork from overburdeig, the packets i the lower priority queue are dropped. 10. The P for every packet i the queue is determied accordig to the followig equatio: For packets i high priority queue: P = P P1 For packets i low priority queue: P = P + P2 Where P1 ad P2 are the pre defied values. By this way both cogestive ad o cogestive packets are served without affectig the quality of service ad deadlie costraits. The overall Priority Queuig Techique The overall algorithm of proposed for priority queueig for deadlie sesitive data trasfers: 1. I the heterogeeous etwork, the umber of packets 4901

4 arrivig at the router is iitially calculated by cosiderig the queue legth as the decidig factor for lettig i the packet or droppig the packet. 2. The the umber of packets departig is determied. 3. Next, the U is calculated. 4. Based o the NCQ techique, the packet queue is divided ito high priority queue ad low priority queue. 5. Based o the packet size ad utilizatio factor criteria, the packets are trasmitted ito the high priority queue ad low priority queue accordigly. 6. The packets i the high priority queue are trasmitted first ad the packets i the low priority queue are equeued. 7. Durig cogestio, the packets i the low priority queue are dropped with higher probability ad the packets i the high priority queue are dropped with lower probability. 8. Thus, the packet trasmissio is performed very efficietly eve durig cogestio. CONCLUSION I this work, a priority queue techique has bee proposed for the routers to avoid cogestio i the heterogeeous etwork. Iitially the utilizatio factor is determied based o the packet icomig rate ad the packet outgoig rate. Next, the packet size is determied ad is compared with the predefied threshold size. Based o the utilizatio factor value ad the packet size, the data packet is moved ito either the high priority queue or the low priority queue. The the data i the high priority queue is trasmitted first ad the data i the lower priority queue is equeued. Durig excessive traffic, the lower priority packets are dropped with higher probability ad higher priority data is dropped with very low priority. Thus, the etwork maitais the high priority data ad trasmits it as quickly as possible. So, this proposed techique is efficiet i cogestio hadlig i the heterogeeous etwork. The future work ivolves the simulatio of eviromet where the realtime data trasfers ad bulk trasfers co-exist ad the QoS parameters like through put, delay ad packet delivery ratio has to be aalysed. REFERENCES [1] G.F.Ali Ahammed ad Reshma Bau, "Aalyzig the Performace of Active Queue Maagemet Algorithms", Iteratioal Joural of Computer Networks ad Commuicatios (IJCNC), Vol: 2, No: 2, March [2] R. Brade, D. Clark, ad S. Shakar, RFC1633 itegrated services i the Iteret architecture: a overview, Jue [3] S. Blake, D. Black, M. Carlso, E. Davies, Z. Wag, ad W. Weiss, RFC2475 a architecture for differetiated services, Dec [4] S. Floyd ad V. Jacobso, Radom Early Detectio Gateways for Cogestio Avoidace, IEEE/ACM Tras. Networkig, vol. 1, o. 4, pp , Aug [5] D.Clark ad W.Fag, Explicit allocatio of besteffort packet delivery service," IEEE/ACM Tras. Networkig, Aug [6] /guide [7] D. Li ad R. Morris, Dyamics of radom early detectio," Proc. SIGCOMM 1997, Sept [8] S. Floyd ad K. Fall, Router Mechaisms to support ed-to-ed cogestio cotrol i the Iteret," IEEE/ACM Tras. Networkig, May [9] R. Mahaja ad S. Floyd, Cotrollig high badwidth flows at the cogested router," i Proc. ICNP 2001, Nov [10] W. Feg, D. Kadlur, D. Saha, ad K.G. Shi, BLUE: A New Class of Active Queue Maagemet Algorithms, Techical Report CSE-TR , Uiv. of Michiga, Apr [11] R. Pa, B. Prabhakar, ad K. Psouis, CHOKe: a stateless AQM scheme for approximatig fair badwidth allocatio," Proc. INFOCOM2000, Mar [12] L. Mamatas ad V. Tsaoussidis, Differetiatig services with o cogestive queuig (NCQ)," IEEE Tras. Computers, [13] L. Mamatas ad V. Tsaoussidis, Differetiatig Services for Sesor Iteretworkig, Proc. IFIP Fifth A. Mediterraea Ad Hoc Networkig Workshop (Med-Hoc-Net 07), Jue [14] L. Mamatas ad V. Tsaoussidis, Less Impact Better Service (LIBS): A Service Paradigm for Iteret Telephoy, Techical Report TR-DUTH-EE , Democritus Uiv. of Thrace, Nov [15] Rahim Rahmai, Christer, Ahlud, Theo Kater, "Desig of Active Queue Maagemet for Robust Cotrol o Access Router for Heterogeeous Networks", EURASIP Joural o Wireless Commuicatios ad Networkig, [16] Kag Mi Lee, Ji Hoo Yag, Byug Suhl Suh, "Cogestio Cotrol of Active Queue Maagemet Routers Based o LQ-Servo Cotrol, Egieerig Letters 16(3), ,

5 [17] Tushar Raheja, "Modellig traffic cogestio usig queig etworks", Idia Academy of Sciece, Vol: 35, Part-4, PP: , [18] Jyothish K Joh, R V Sivabala, Survey o Router Policies Providig Fairess ad Service Differetiatio Favorig Real-Time Data Trasfers i Iteret Advaces i Itelliget Systems ad Computig Volume 324, 2015, pp ,April