Software Agent (SA) to guarantee QoS for multi constrain applications in all-ip networks

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1 Software Agent (SA) to guarantee QoS for multi contrain application in all-ip network Kazi Khaled Al-Zahid and Mituji Matumoto GITS, Waeda Univerity 94 Waeda Univ. Bldg. A-308, 1011Okuboyama Nihitomida Honjo-hi Saitama Japan Keyword: Software agent, QoS decriptor, QoS reource matrix Abtract The emergence of new application in heterogeneou network environment force u for new adaptation to erve in emergencie with acceptable Quality of Service (QoS). The proliferation of demand to reach emergency ervice profeional uing bet effort Internet ha everal inherent problem. The end to end QoS in IP network i largely depend on the amount of reource allocated for the traffic. To achieve deired QoS, IP network can ue either over proviioning or explicit reource management. But over proviioning of network ometime caue reource unued and become the bottleneck of the ytem. To define an End-to-End (ETE) QoS require a common agreement between different adminitrative boundarie for reource management mechanim while the individual ha their own reource policy and traffic engineering method. For thi reaon we need a common language (a QoS ignaling protocol) for communicating end to end traffic a well a repecting the different individualitie of the autonomou operation of the travered domain. Here we propoed a dynamic differentiated ervice approach for emergency traffic o that during emergency ituation the router in the ource-detination path configure themelve uing Software Agent (SA) to erve the high priority traffic with optimum effort. The dynamicity of the ytem i that it doe not depend on a ingle contraint of the route election rather it impoe numerou factor to qualify it QoS need. With the help of SA and Quality of Service Decriptor (QoSD-Quality of Service Specification) we howed how to achieve better QoS for time enitive emergency traffic over the bet effort Internet. 1 Introduction The implicity and flexibility of IP protocol ha led to the fact that IP over everything. But an intenive reearch i till under conideration how to provide bet QoS uing IP network for high priority traffic. Switching to IP a a main delivery method look increaingly promiing. Until now there i no tandard method available including the application, tranport and network layer for guaranteed QoS baed on the application preference. Therefore, we need a tandard QoS pecification, and architecture to map the application requirement in the available communication network. It hould include the broad pectrum of availability, erviceability, performance, operation and other ervice attribute for both uer QoS d input Control Required Software output entity Reource Reult Figure 1: Block diagram of Software Agent and Service Provider (SP). But, till there i no uch Service Level Agreement (SLA) which can dynamically handle thee ETE requirement. In imple term dynamic creation of SLA i the procedure through which a cutomer can electronically pecify the characteritic of the ervice the end uer wih to have and the network will decide whether it can accommodate or not. The interaction between the SP and the end uer mut be done through a tandard form baed on the ervice level pecification philoophy. The reulted dynamic SLA give the cutomer the potential to have acce to value added ervice [1]. So, thi pecification hould be generic and behave equal to both upcoming new application and previou legacy application. In thi paper, we preent a trategy for ETE QoS management in IP network baed on the ue of agent. The main part ofthepaperiinitiatedinsection3and4byahortreview of the QoS problem in the Internet and a motivation for the introduction of agent in networking in general and oftware agent, in particular. In Section 5, the adopted reference architecture i decribed. Section 5.4 preent the algorithm for implementing the route election procedure. Finally, Section 6 preent the concluion and point out to future work and poible extenion. 2 QoS and Agent in Internet QoS i related to multimedia application and i characterized by quantitative meaure, expreing ubjective and objective criteria in term of uer atifaction. Uer atifaction by and large depend on the timeline by which continuou media like audio and video data are preented in a ditributed etting, expoing the data to tranport and proceing of variou kind [2]. Agent are the autonomou program ituated within an environment, which ene it and act upon it uing it knowledge bae, and learn o a to act in future. Agent are clai-

2 fied a: local or uer interface agent, networked agent, ditributed artificial intelligence agent and mobile agent baed on the attribute they poe. In thi paper we ued programmable oftware agent. A major incentive for an agent-baed approach i that policie can be implemented dynamically, allowing for a reource tate-baed admiion and reervation trategy [2]. Agent can carry application pecific knowledge into the network at location where it i needed. The popularity of the agent technology i due to it upport to: component baed oftware engineering, flexible operation, eay oftware maintainability, adaptability to the real world, and extenibility of the oftware [3]. Figure 1 how the functional block diagram of Software Agent. 3 Signaling iue in QoS Implementing QoS for internet packet handling i not a imple a we ketch. However the eparation of ignaling at the application layer from the QoS ignaling at the IP layer doe not reduce the interaction between the two ignaling layer. Becaue meage of Seion Initiation Protocol (SIP) [4] which i widely ued for ignaling in Internet can take different path than the media packet travel and a a conequence SIP erver have no acce to the media path. Previouly, call ignaling on a circuit-witched network wa ufficient to provide preferential call etup and a clear ounding call. Thi i becaue ignaling reerve reource for a voice channel along the path between caller and callee [5]. It i aumed that the network infratructure work correctly and that emergency communication are to be given preferential treatment to remaining reource. However, IP network do not function in the ame way and hence new analyi i required. In general the acce to Internet can be claified in three top categorie. Source acce network, core tranit network and detination acce network. The acce device in thee area are called Edge, Core and Border router repectively. Different reearch tated that there are no ignificant change in call etuptimeevenifweueqosignalingwithsipduringcall initiation phae. Actually eion etablihment i independent of QoS with generic call flow of SIP method. Therefore, prioritized SIP ignaling doe not olve the call quality iue rather it require pecial mechanim to handle the packet in the media tream. IP QoS aurance or over proviioning network reource can give better call quality. QoS i available in IP network but no integration i yet done over multiple SP [5] for guaranteed flow. So a new buine rule i neceary to integrate the SP to create QoS reponive ytem for emergency traffic. Variou reervation oriented approache can be adopted to provide preferential treatment for emergency traffic uch a reource conervation approach, preemption approach, delay baed policy etc [6]. But in mot cae we face ome diadvantage of adopting the policy to deploy it in practical ituation. Rather uing per flow ignaling it i deirable to ue packet level ignaling o that the router can handle it dynamically. 4 QoS and routing The traditional hortet path routing work fine for bet effort Internet but too retrictive for QoS traffic, becaue there may exit plenty of alternative path that can upport the required QoS while the hortet path cannot. Though Dijktra[7] and Bellman Ford[8] algorithm are optimal and run in polynomial time, they can not find route, that atify multiple QoS contrain, uch a bandwidth, delay, delay jitter, lo probability which required for variou multimedia application. The factor like adminitrative policie, performance requirement, load balancing, calability etc. have increaing ignificance in Internet routing. Intelligent path election baed on multiple contraint or on packet content take thee factor into conideration. Contraint-baed routing [9] denote a cla of routing algorithm where path election depend on a et of requirement or contraint, in addition to the detination. Thee contraint may be impoed by adminitrative policie, or by QoS requirement. Contraint impoed by policie are referred to a policy contraint, and the aociated routing i referred to a policy routing. Contraint impoed by QoS requirement, uch a bandwidth, delay, or lo are referred to a QoS contraint, and the aociated routing i referred to a QoS routing [10]. Both QoS-baed routing and policy-baed routing can be conidered a pecial cae of contraint-baed routing. 4.1 Network Model We imply aume that a communication network can be modeled uing a graph G = (V,E) where V i the et of node which could be router, erver or witche and E repreent the et of edge or link of the network. For any conecutive node u, v the link e(u, v) can be expreed for different parameter a h(e) =h(u, v), c(e) =c(u,v), d(e) = d(u,v), j(e) =j(u,v), b(e) =b(u, v), l(e) =l(u,v) are the hop, cot, delay, jitter, bandwidth, lo function of the link e, where the link eɛe i directly connected by uɛv and vɛv. The claification of thee parameter are hown in Table 1. Thee parameter may occur in both node or edge. And thee have either poitive or non-negative impact over the communication network. Therefore we define thee parameter for either node or edge with the function QCF(n): V M/M + and QCF(e): E M/M + where QCF i QoS Contrain function, nɛv, eɛe and M and M + denote poitive and nonnegative value repectively. QoS for different parameter can be expreed uing following relation [1-5]. bandwidth: b(p(, d)) = min{b(e) eɛp(, d)} (1) delay: d(p(, d)) = Σ eɛp(,d)d(e) +Σ eɛp(,d)d(n) (2) delay-jitter: j (p(, d)) = Σ eɛp(,d)j(e)+σ nɛp(,d)j(n) (3)

3 QoS Contraint Available link bandwidth, b Link propagation delay, d Delay jitter, j Lo probability (or error rate), l Cot, c Hop count, h Type Concave (min/max) Multiplicative Uer application QoS layer Network layer Table 1: Different Network Parameter lo-probability: l (p(, d)) = Π nɛp(,d) l (n) (4) cot: (p(, d)) = Σ eɛp(,d) c(e) +Σ nɛp(,d) c(n) (5) Where p(, d) i the path from ource to end node d and l i the probability of no packet lo. The problem to find a path between ource node to the detination node d, P (, d) = (, i, j, k,..., l, d), uch that it would atify all QoS contraint, from ource to detination. The above contraint can be categorized in two group: link contraint and path contraint. Path contrain again conit of two clae: additive and multiplicative. Serving application that require both of thee contrain imultaneouly i yet an unolved problem. Up to now there i no optimal olution or routing technology, which can atify all of thee contraint to find an optimal path between the ource-detination peer. The ETE QoS parameter may alo include parameter uch a cutom uer and admin policy (Service Level Specification) for deired tranmiion. 5 Deign overview In thi work, we have propoed a QoS mapping framework which conider both cutomer and adminitrative policy, qualitative and quantitative QoS contrain over the internet differv domain. We did not conider any central mechanim uch a the bandwidth broker or any adaptive bandwidth cheme. Rather we conidered SA that depend on the local tate information to atify the end uer. Thu, in our approach, multi contraint QoS D i ued for QoS mapping, requeted in different degree by uer application, anticipating different level of guarantee (or aurance) according to the ervice, the end uer want. The QoS control take place in the form of aigning each packet with an appropriate QoS level. The application layer i reponible for generating the QoS D and ending it to the ingre of a differentiation-enabled domain to manage traffic according to the traffic conditioning agreement pecified in the SLA. Baed on the requeted traffic ource detination information, the SA dynamically configured the neceary interface o that, only the traffic marked a high priority will get the privilege while the BE traffic remain ame and behave a uual. If the SA can atify the requeted QoS D, the proce continue forward to reach the detination, otherwie notification i end to the ource that current network i unable to meet the requeted QoS contrain. Figure 2: Architectural Model R Bandwidth Cot Delay Jitter Lo-prob. R 0 M 00 M 01 M 02 M 03 M 04 R 1 M 10 M 11 M 12 M 13 M 14 R 2 M 20 M 21 M 22 M 23 M 24 Table 2: QoS reource matrix 5.1 Traffic marking for media packet Traffic marking i an eential component of the differv architecture. The traffic marker look at the incoming packet and compare it with a given traffic profile (for example, a token bucket characterization of a SLA between two domain). In-profile packet are marked with an identifier that indicate a higher priority. If packet are out of profile, it i marked with a lower priority. The key iue here i marking the emergency packet uing IP Type of Service (TOS) byte or DiffServ Code Pint (DSCP). 5.2 Formation of QoS decriptor We aume the traditional architectural model with little change hown in figure 2. The haded portion are tranport, data link and phyical layer are out of the cope of our dicuion. Here we aumed additional QoS layer to generate the QoS decriptor which take part in finding feaible path with multiple contrain. During media packet tranmiion thi layer ha no role at all and application never tart ending media packet untill the path i etablihed. The ample QoS decriptor i hown in figure 3. The field value of the QoSD i elected dynamically by end uer application with the collaboration of QoS layer. The parameter in the decriptor hold the value in the form of <Σ/Π, Req>, whereσ/π i either ummation or product of the value from ource to lat viited node that accept the QoSD and Req denote the required ETE value to be atified. Initially the Σ/Π i et with zero. Hot application generate the QoS decriptor and end it to the edge router (ource node) to find a feaible path to detination. 5.3 The QoS tet with SA The QoS tet at each node i to check whether there are ufficient reource for meeting the multiple QoS contrain. Thi i done by the QoS mapper of the SA at the router

4 Figure 3: QoS decriptor or witche. The QoS mapper poee a 2-dimenional reource matrix hown in Table 2 that map different network reource parameter with it neighbor router entity. In Table 2 R denote the current viiting node that meet all the requeted contrain of hot application and R 0,R 1,R 2 are attached neighbor with R. M ij (where i i the router entity and j i the contrain) in the reource matrix denote the value of contrain with the attached interface. The programmable SA i tightly coupled with the router hardware and alway update (baed on period or trigger) itelf whenever any change occurred in the connected router entity. The main advantage of uing SA to help a a admiion controller to find a path with the requeted QoS contrain. A a conequence the objective of the SA at any node i i to check the conitency of the following relation [6-10] to optimize the requeted QoS D. Min (b(e ei 1ɛP i 1 )) Bpec (6) d(e) Dpec (7) j(e) Jpec (8) Π i 1 l (e) Lpec (9) c(e) Cpec (10) The path election i divided in two phae- oft tate and hard tate. During oft tate if SA i accept the REQUEST from SA i 1, then SA i prohibit the SP (router entity) to accept any new reource requet from other until the current REQUEST die or oft tate finally commit in hard tate. If SA i fail to qualify any one of the inequalitie hown above, a REJECT reply i end to SA i 1o that SA i 1can trigger the routing algorithm to find the next alternate path to the detination. From the above decription, it i eay to undertand that SA can upport a many a QoS contrain a the application require. Addition of a new contrain i jut to include it in the reource matrix at each node o the QoS mapper can take care off the incoming QoSD requet for new contrain. For end-to-end QoS different application require different type of parameter which ometime combination of additive, non-additive and policy contrain. So far there i no routing algorithm that can handle uch a mix of routing in wired or wirele environment for uer atified communication. The uer alway trie to minimize it tranmiion cot keeping the tandard quality a much a poible. While the traditional routing algorithm doe care for quality, if cot minimized algorithm i ued. 5.4 QoS Route election We avoided to introduce new protocol and propoed the algorithm baed on exiting protocol and technology. To achieve optimal performance we aume the following: 1. Topology information can be obtained from exiting link tate protocol uch a Open Shortet Path Protocol (OSPF) [11]. 2. Rather than conidering the whole path, hop by hop parameter optimization i conidered to reach the final detination. 3. Programmable SA and the correponding routing entity i tightly coupled in uch a way, if any change occur with the routing entity a notification i end to the SA to make neceary change in the reource matrix. Here, hop by hop routing mean, routing deciion are made in each router with local information by the SA. Actually we ued the mixture of hop by hop and ource baed routing for propoed algorithm. Multi contrain baed routing i very complexanddealingwithittofindafeaiblepathiannpcomplete problem [12]. In lat decade huge number of algorithm i propoed for both policy and QoS baed routing. Several heuritic algorithm i alo propoed to olve thi problem. Wang and Crowcroft have argued that uing bandwidth a the firt dicriminating characteritic i often efficient ince bandwidth affect many of the remaining QoS parameter. Therefore in our algorithm we maintain a topological order (uch a bandwidth, delay, cot, delay-jitter, lo-probability, etc.) o that the important parameter i checked firt by the SA. Our algorithm take an ub-optimal path earch approach for the elected QoS contrain. The required input parameter i the QoSD which include the ource (), detination (d) and multiple QoS criterion (Q). In thi algorithm R[,..., d] denote the et of node that are involved in the path o far, while V i the total number of node in entire network. Firt, QoSD i puhed forward from to the next hop router through the primary index path which i alo hortet path baed on the traditional routing table. If SA at node i accept the requet then a oft tate i iued and the route vector i updated

5 to R[,..., i,...d]. SA alo tore the partial route until the oft tate end and no new QoS proviioning i accepted for the reource until the oft tate complete. If QoSD reache the detination, ACCEPT reply carried back to the ource in the revere unicat path in which QoSD reache to the detination. When a router receive a QoSD meage, if the QoS tet fail, SA end the NACK meage back to the lat router that accept the requet. When an infeaible link i encountered, the QoS routing protocol trie to find the alternate route. Without knowledge of global information SA earche for multiple path for one that can upport the requeted QoS contrain. To find a bet candidate path, firt aetofpaths hk i (where i can be any node except the detination) i elected with increaing hop number, where h k = <h min,...,h max > and all the link of the elected et of path atify the minimum bandwidth required by the application. We ued bandwidth to elect the et of path to detination from any node. SA then detour the QoS D through the alternate path. If the link (i, j) i ued then SA j performed imilar tet for the requeted QoS contrain a SA i did. In every node QoS mapper check both additive and non-additive QoS contraint and keep the accumulated value until the current oft tate or hard tate end. If SA j fail and end NACK then SA i end the QoS D in the next alternate path but with the accumulated tored value in SA i rather uing the accumulated value it calculated in lat viited node j. The programmable SA can trace back when it face infeaible link that fail to atify the requeted QoS contrain. The algorithm run repeatedly until it find any path to detination if there i any. QoS D can be end with current accumulated value of the contrain from the tored value at any time when it i looking for alternate path. To find the route uing QoS D properly, it require a et of tandard which hould be implemented in the SA. Non emergency traffic that goe in the ame route may experience delay due to the high precedence of QoS traffic. But it depend on how SA want to atify the requeted QoS contrain to adjut the router to handle high priority traffic. Another advantage of thi approach i, SA can dynamically tune only thoe ub interface where emergency traffic actually flow and other IP interface can be remain untouched. When a eion i cloed SA can readjut the router tate for uual operation according to SP need. Moreover SA can end advance warning meage to other ame priority or low priority tream to inform them to chooe either different path or low down their tranmiion to avoid congetion and lo of tranmiion quality. agent which work a complement with the exiting technology. A a future work we are now working for imulating the propoal for both wired and wirele environment. REFERENCES [1] D. Kagkli, N. Liampoti, and C. Takiri, A framework for implicit and explicit ervice activation baed on ervice level pecification, in Proceeding of the 2004 ACM ympoium on Applied computing, pp , ACM Pre, [2] A. P. Hermann De Meer, Aurelio La Corte and O. Tomarchio, Programmable agent for flexible qo management. [3] S. Manvi and P. Venkatram, Application of agent technology in communication: a review, Computer Communication, ELSEVIER, vol. 27, pp , [4] E. S. M. Handley, H. Schulzrinne and J. Roenberg, SIP: Seion Initiation Protocol, RFC 2543, IETF, Mar [5] K.S. King and S. Bradner, Internet emergency preparedne in the IETF, Application and the Internet Workhop, Proceeding Sympoium on, 27-31, Jan [6] Cory Beard, Mechanim for providing internet emergency ervice, tech. rep. [7] E. W. Dijktra, A note on two problem in connection with graph. Numer. Math., IASTED/ACTA Pre., vol. 1, pp , [8] C. Hedrick, Routing information protocol, Tech. Rep. Internet Requet for Comment 1058, [9] O. Youni and S. Fahmy, Contraint-baed routing in the internet: Baic principle and recent reearch, [10] O. Youni and S. Fahmy, Contraint-Baed Routing in the Internet: Baic Principle and Recent Reearch, [11] V. Paxon, End-to-end routing behavior in the Internet, in Proceeding of the ACM SIGCOMM Conference on Application, Technologie, Architecture, and Protocol for Computer Communication, vol. 26,4 of ACM SIGCOMM Computer Communication Review, (New York), pp , ACM Pre, Augut [12] I. Cidon, R. Rom, and Y. Shavitt, Multi-path routing combined with reource reervation, in INFOCOM (1), pp , Concluion and Future work In thi paper, we have propoed a QoS-baed routing architecture to erve multi-contrain ETE high priority application. According to the propoal, the uer can be electronically pecify their QoS requirement from the hot application baed on their preference. Although, the propoed ytem ha ome performance limitation, but a a whole it i flexible, becaue the routing functionality i completely done by the