Prioritized Traffic Recovery over GMPLS Networks

Transcription

1 Pioitized Taffic Recovey ove GMPLS Netwoks 2005 IEEE. Pesonal use of this mateial is pemitted. Pemission fom IEEE mu be obtained fo all othe uses in any cuent o futue media including epinting/epublishing this mateial fo advetising o pomotional puposes ceating new collective woks fo esale o ediibution to seves o lis o euse of any copyighted component of this wok in othe woks. This mateial is pesented to ensue timely dissemination of scholaly and technical wok. Copyight and all ights theein ae etained by authos o by othe copyight holdes. All pesons copying this infomation ae expected to adhee to the tems and conaints invoked by each autho's copyight. In mo cases these woks may not be epoed without the explicit pemission of the copyight holde. Citation: Yuanqiu Luo and Niwan Ansai Pioitized Taffic Recovey ove GMPLS Netwoks Poc IEEE Sanoff Symposium Pinceton NJ Apil pp URL:

2 Pioitized Taffic Recovey ove GMPLS Netwoks Yuanqiu Luo and Niwan Ansai Advanced Netwoking Laboatoy Depatment of Electical and Compute Engineeing New Jesey Initute of Technology Univesity Heights Newak NJ USA Abact- This pape poposes the pioitized taffic ecovey model fo genealized multipotocol label switching (GMPLS) netwoks. The netwok taffics ae diffeentiated into fou classes with the highe pioitized class achieving the dedicated potection the second pioitized class obtaining the shaed eoation the thid pioitized class attaining the on-line eoation and no ecovey fo the lowe pioitized class. The QoS pefomance of such a model is evaluated by extensive simulations. The esults show that the delay sensitive taffic eceives the sevice of the fae ecovey the thoughput sensitive taffic with light load takes longe ecovey time and the thoughput sensitive taffic with heavy load expeiences the lowe ecovey sevice. I. INTRODUCTION With the explosion of Intenet taffic and the migation of pioitized taffic netwok suvivability has become a citical pefomance issue. Thee has been a ecent intee in povisioning suvivability in a common contol and measuement plane i.e. genealized multipotocol label switching (GMPLS) to educe taffic ecovey edundancy esulted by assigning diffeent ecovey mechanisms to diffeent layes [1]. Besides packet switching GMPLS also suppots the switching in the time wavelength waveband and space domains. It combines IP-based contol plane techniques with the povisioning capabilities of divese switches to suppot enhanced netwok suvivability. The ecovey mechanism of GMPLS povides SONET esiliency featues and thus the IP taffic could be placed diectly ove the WDM laye [2]. The IP signaling and outing potocols ae extended by including the taffic engineeing (TE) infomation [3] to facilitate taffic ecovey. This pape poposes a pioitized taffic ecovey model fo GMPLS netwoks. The netwok taffics ae diffeentiated into classes and a diffeent class is assigned a diffeent ecovey scheme to achieve diffeent ecovey sevices. The QoS pefomance of such a model is analyzed to delineate the tadeoff between the netwok esouce utilization and the netwok suvivability. We show that such a pioitized taffic ecovey model is effective in achieving a good taffic ecovey sevice diffeentiation. This pape is oganized as follows. The pioitized taffic ecovey model is pesented in Section II followed by the pefomance evaluation in Section III and the conclusions in Section IV. II. PRIORITIZED TRAFFIC RECOVERY MODEL The majo objective of taffic ecovey is to minimize the sevice inteuptions while efficiently utilizing netwok esouces. It is expensive to povide a high degee of ecovey fo all taffics. Theefoe poviding diffeentiated ecovey sevice is gowing in impotance [4]. GMPLS netwoks need to suppot a vaiety of sevice guaantees in which a diffeent sevice class obtains its coesponding degee of taffic ecovey [2] [5]. Table 1 illuates ou pioitized ecovey model. It defines fou sevice classes: gold silve bonze and be effot. The gold class taffic is delay-sensitive and the netwok commits to delive it with the minimum delay. The ecovey scheme fo the gold class taffic is dedicated path potection (DPP). DPP pecomputes a link-disjoint backup path fo each woking path and one backup path is eseved only fo a specific woking path not shaed with othes. Upon detection of a failue the taffic on the woking path is switched into the backup path to guaantee the fae ecovey. TABLE 1 PRIORITIZED TRAFFIC RECOVERY MODEL Sevice class Class featue Recovey scheme Gold Delay-sensitive Dedicated path potection Silve Thoughput-sensitive (lighte loaded) Shaed path eoation Bonze Thoughput-sensitive (heavie loaded) On-line eouting Be effot No sevice guaantee None The silve class taffic is thoughput sensitive and the netwok commits to delive it with high pobability. The coesponding ecovey scheme is shaed path eoation (SPR). SPR assigns a disjoint backup path fo a woking path while the backup esouces can be shaed among diffeent backup paths as long as thei coesponding woking paths ae disjoint. Upon detection of a failue the links along the backup path ae allocated on-line. This equies ecovey signaling which is suppoted by GMPLS signaling potocols. The bonze class taffic is thoughput sensitive with heavie load and lowe ecovey pioity than the silve one. On-line eouting (OLR) is applied. OLR eoutes the disupted taffic based on the available spae netwok esouce infomation. The be effot taffic has the lowe pioity and does not expect guaantees fom the netwok. It is consideed only afte the equiement of all othe types of taffics is met. Theefoe

3 no scheme is assigned to ecove it and we will not discuss the be effot taffic ecovey in this pape. In the following we fomulate the above ecovey schemes. In a netwok G(NE) whee N is the node set and E is the link set define (ij) as the link between nodes i and j; (st) epesents the incoming taffic equiement fom souce node s to deination node t; (xy) ands fo the cuent netwok taffic (xy) T whee T is the taffic set; and P is the woking path fo taffic equiement (xy). We also assume link (ij) suppots W channels and an entie channel is allocated to a single taffic equiement. We define the following indicatos: 1 if P uses link ( i j) O = 0 othewise 1 if the backup path fo P uses link ( ) B =. 0 othewise Among the TE infomation the advetised shaed isk link goup (SRLG) infomation is citical fo esouce shaing [6]. An SRLG is the set of links shaing a common physical esouce. When the shaed esouce fails all the links in this SRLG ae disconnected. Any link in such a set is said to be in this SRLG. A path is in SRLG if at lea one of its intemediate links is in SRLG. Two paths ae SRLG-disjoint if neithe of them is in the same SRLG. SRLG-disjoint paths do not shae any isk. The known SRLG infomation is: : SRLG R whee R is the SRLG set 1 if P is in SRLG L = 0 othewise 1 if link ( i j) is in SRLG Z =. 0 othewise A. Gold Class Taffic Recovey DPP is assigned to the gold class taffic. To suvive all of the intemediate single failues in the woking path and to pevent the woking and backup paths fom failing at the same time the backup path mu be SRLG-disjoint and link-disjoint fom its coesponding woking path. The known paametes in DPP include: netwok topology G(NE) cuent taffic set T woking paths configuation fo cuent taffic O and SRLG infomation L and Z. The pimay woking path fo the incoming taffic equiement fom s to t i.e. P is detemined by the shote path outing algoithm and the coesponding path configuation indicato O is known. The poblem is to detemine the backup path indicato B and minimize the esouces employed fo the backup path fom s to t. That is Minimize B. (1) ( i j) E Such a minimization objective is subjected to seveal sets of conaints. The flow continuity conaints shown in Eq. (2) guaantee that in the backup path fom s to t souce node s only has outgoing flow deination node t only has incoming flow and the flow at the intemediate nodes is balanced. 1 i= s B 1. B = ji i= t (2) j N j N 0 i The SRLG-disjoint conaints in Eq. (3) impose the backup path being SRLG-disjoint fom its woking path. The linkdisjoint conaints in Eq. (4) guaantee the backup path being link-disjoint fom its woking path. Besides link-disjoint fom its woking path such a backup path should also be linkdisjoint fom the cuent woking paths as indicated in Eq. (5) B L Z = 0 ( i j) E R. (3) OB = 0 ( ) E. (4) O B = 0 ( i j ) E ( x y ) T. (5) The link capacity conaints in Eq. (6) ensue the sum of the woking and the backup taffic on a link is no moe than the link capacity W. ( O + B + O + B ) W ( i j) E. (6) ( ) T B. Silve Class Taffic Recovey SPR is assigned to the silve class taffic in which the backup path is not dedicated. Unde the assumption that at mo one failue occus at any time spae esouces can be shaed among disjoint (both SRLG-disjoint and link-disjoint) woking paths as many as possible to achieve highe efficiency. Hee the known paametes ae the same as DPP and SPR is fomulated as Maximize B B. (7) ( ) E( ) T Two backup paths shae the same link if = 1 maximizing such shaing among the backup path is the objective of SPR. The same flow continuity conaints of Eq. (2) as in DPP apply fo SPR. The SRLG-disjoint conaints in Eqs. (8) and (9) impose the backup path being SRLG-disjoint fom its woking path. A woking path and its coesponding backup path ae SRLG-disjoint iff B L Z = 0. Two woking

4 paths ae SRLG-disjoint if LL = 0. The link-disjoint R conaints in Eq. (10) ensue the backup path being linkdisjoint fom its woking path. B LZ = 0 ( ) E R. (8) LL B B = 0 ( ) T ( ) E. (9) ( ) R OB = 0 ( ) E. (10) The link capacity conaints in Eq. (11) ensue that one channel suppots at mo one woking path while it may suppot seveal backup paths if possible. Moeove the sum of the woking and the maximum backup taffic on a link is uppe-bounded by the link capacity W. ( ) T } ( ) T O + O + max B B W ( i j) E. (11) C. Bonze Class Taffic ecovey OLR ecoves the bonze class taffic afte a single link failue has been detected. Netwok link ate infomation especially the bandwidth availability is necessay to eoute. The known paametes include: the netwok topology G(NE) the cuent taffic set T the woking paths configuation fo the cuent netwok taffic O and the SRLG infomation L and Z. The followings about netwok failue ae also known: T: the disupted taffic(s) E: the failed link. OLR aims to employ the lea netwok esouces to ecove the taffic inteuption. To avoid futhe taffic disuption the eouting path is disjoint fom the untouched woking path. Such a poblem is fomulated as Minimize B. (12) ( i j) E E ( s) t T In the eouting path the same flow continuity conaints in Eq. (2) ae applied. The SRLG-disjoint conaints in Eq. (13) impose the eouting path being SRLG-disjoint fom all of the woking paths. The link capacity conaints in Eq. (14) ensue that the sum of the woking taffic and the eouting taffic in a link is uppe bounded by the link capacity. B L Z = 0 ( s t) T ( x y) T T ( i j) E E R. ( ) T T ( ) T (13) O + B W ( i j) E. (14) III. RESULTS AND DISCUSSIONS Simulations ae conducted in the NSFNET with 14 nodes and 21 bidiectional links. Each link contains 8 channels. 6 SRLGs ae placed in the netwok with each SRLG containing 2 links in the netwok and the coesponding SRLG infomation is advetised among the contol plane. Dynamic taffics ae accommodated with each taffic possibly teminating afte a cetain duation. The souce and deination nodes ae evenly diibuted among all nodes and each taffic occupies one channel bandwidth. Among all taffics the pobabilities of the gold silve bonze and be effot class taffic ae 10% 20% 30% and 40% espectively. The backup paths fo the gold class taffic is peconfigued to ensue the shote outing and the disjoint conaints. The backup path fo the silve class taffic is pedecided while on-line configued. The ecovey path fo the bonze class taffic is computed afte a failue has been detected. The majo paamete of QoS pefomance inveigated is the ecovey time. Recovey time is the time between the failue occuence and the time that the disupted taffic is ecoveed. Such an inteval is indicative of the potential data and evenue loss and depends on the failue location the ecovey scheme and the popagation delay along the backup path. Recovey time of diffeent taffic is collected by initiating single link failues on all links one by one. We assume failue detection time D and failue notification time C ae both andomly diibuted fom 0.1 to 0.2ms. Taffic switching time S indicates the time duation that the taffic is successfully switched fom the disconnected path to the backup path and vaies in the ange fom 1 to 2ms. The bonze taffic takes online pocessing time K to decide the eouting path and K anges fom 100 to 300ms in ou simulation. Intemediate link esevation is necessay when ecoveing the silve and bonze taffic. We assume the time of eseving a link is exponentially diibuted with mean β. Fig. 1. Recovey time vs. time to eseve a link. As shown in Fig. 1 the ecovey time fo the silve and bonze class taffic inceases as the mean time of eseving a link i.e. β is longe. The sevice of ecovey time fo diffeent taffic is classified as: the gold class obtains able and the

5 fae ecovey the silve class achieves the medium class ecovey which depends on the aveage link esevation time and the bonze class takes the longe ecovey time. The eason is that all the intemediate switches ae peconfigued in the ecovey path of the gold class taffic and thus the ecovey time is independent of the link esevation time. The othe two classes take moe time fo taffic ecovey fo they need to eseve the links on the ecovey path afte a failue occus. The ecovey time of the bonze class taffic is the longe one and mo of the time is spent on the ecovey path computation. IV. CONCLUSIONS The pioitized taffic ecovey model has been poposed to povide sevice diffeentiation ove GMPLS netwoks. The delay sensitive taffic is assigned as the gold class taffic and the netwok commits DPP to ecove it. The thoughput sensitive taffic is classified into silve and bonze classes. Fo the silve one that has lighte load SPR is employed to eoe the disconnected taffic; fo the heavily loaded bonze class taffic OLR is adopted. Thee is no ecovey commits fo the be effot taffic. Simulations have demonated that the sevice diffeentiation with espect to ecovey time is held with the gold class taffic obtains the fae ecovey sevice the silve one attains the middle level ecovey sevice and followed by the bonze one. REFERENCES [1] Genealized multi-potocol label switching achitectue Intenet Daft daft-ietf-ccamp-gmpls-achitectue-07.txt May [2] Analysis of genealized multi-potocol label switching (GMPLS)-based ecovey mechanisms (including potection and eoation) Intenet Daft daft-ietf-ccamp-gmpls-ecoveyanalysis-02.txt Sep [3] Genealized multi-potocol label switching (GMPLS) signaling esouce esevation potocol-taffic engineeing (RSVP-TE) extensions IETF RFC [4] J. Hu: Divese outing in optical mesh netwoks IEEE Tansactions on Communications vol. 51 no. 3 pp Ma [5] S. K. Lee D. Giffith V. Coussot and D. Su: Explicit outing with QoS conaints in IP ove WDM IEE Poceedings on Communications vol. 149 no. 2 pp Apil [6] D. Xu Y. Xiong C. Qiao and G. Li: Tap avoidance and potection schemes in netwoks with shaed isk link goups IEEE Jounal of Lightwave Technology vol. 21 no. 11 pp Nov