A Scheme to Reduce Packet Loss during PMIPv6 Handover considering Authentication

Transcription

1 Inernaional Conference on Compuaional Sciences and Is Applicaions ICCSA 2008 A Scheme o Reduce Loss during P Handover considering Auhenicaion Seonggeun Ryu, Gye-Young Kim, Byunggi Kim, and Youngsong Mun School of Compuing Soongsil Universiy, Korea sgryu@sunny.ssu.ac.kr, {gykim11, bgkim, mun}ssu.ac.kr Absrac Mobile IPv6 () is a presenaive proocol which suppors global IP mobiliy. causes a long handover laency ha a mobile node () doesn send or receive packes. This laency can be reduced by using Proxy Mobile IPv6 (P). P is a proocol which nework suppors IP mobiliy wihou paricipaion of he, and is sudied in Nework-based Localized Mobiliy Managemen (NETLMM) working group of IETF. There is much packe loss during handover in P, alhough P reduces handover laency. In his paper, o reduce packe loss in P we propose Lossless P (PL-P) wih auhenicaion. In PL-P a previous mobile access gaeway (pmag) regisers o a Local Mobiliy Anchor (LMA) on behalf of a new MAG (nmag) during layer 2 handoff. Then, he nmag buffers packes during handover afer regisraion. Therefore, PL-P can reduce packe loss han hem in and P. Also, we use Auhenicaion, Auhorizaion and Accouning () infrasrucure o auhenicae he and o receive s profiles securely. We shows performance of PL-P hrough comparison of packe loss during handover of, P and PL-P. 1. Inroducion In wireless/mobile neworks, mobile nodes () can change heir aachmen poins while hey communicae wih corresponden nodes (CN). Hence, mobiliy managemen is essenial for racking he s curren locaions so ha heir daa can be delivered correcly. IP-based mobiliy managemen is criical, since he nex-generaion wireless/mobile neworks are anicipaed o be unified neworks This research was suppored by Minisry of Knowledge Economy, Korea, under he Informaion Technology Research Cener suppor program supervised by he Insiue of Informaion Technology Advancemen. (gran number IITA-2008-C ) based on IP echnology. Mobile IPv6 () [1] from he Inerne Engineering Task Force (IETF) is sandardized for mobiliy managemen in IPv6 wireless/mobile neworks. Mobile IPv6 requires clien funcionaliy in he IPv6 sack of a mobile node. Exchange of signaling messages beween he and a home agen (HA) enables he creaion and mainenance of binding beween he s home address and is care-of address. Mobiliy as specified in requires he IP hos o send IP mobiliy managemen signaling messages o he HA, which is locaed in he nework. is a approach of hos-based mobiliy o solve he IP mobiliy challenge. However, i akes a long ime o process handover and here is much packe loss during handover, since here are many signaling messages via wireless link which occurs long delay during handover. Nework-based mobiliy is anoher approach o solving he IP mobiliy challenge. I is possible o suppor mobiliy for IPv6 nodes wihou hos involvemen by exending signaling messages and reusing he HA. This approach o supporing mobiliy does no require he o be involved in he exchange of signaling messages beween iself and he HA. A Mobile Access Gaeway (MAG) in he nework performs he signaling wih he HA and does he mobiliy managemen on behalf of he aached o he nework. This proocol is called as Proxy Mobile IPv6 (P) [2] in Nework-based Localized Mobiliy Managemen (NETLMM) working group of IETF. P can reduce handover laency, since he proxy mobiliy agen on behalf of he performs handover process. Tha is, here are a lile signaling message via wireless link. There is much packe loss during handover in P, alhough P reduces handover laency. In his paper, o reduce packe loss in P we propose - Lossless P (PL-P) wih auhenicaion. The similar scheme was sudied o reduce packe loss and handover laency in, such as fas handovers for (F) [3]. In PL-P, a previous MAG (pmag) regisers o a Local Mobiliy Anchor (LMA) on behalf of a new MAG (nmag) during layer 2 handoff. Then, he /08 $ IEEE DOI /ICCSA

2 p-mag n-mag LMA p-mag n-mag LMA Layer2 Handoff Aached Aached Reques Response PBU Figure 1. Signaling flow of P wih Auhenicaion. nmag buffers packes during handover afer regisraion. Therefore, PL-P can reduce packe loss han hem in and P. Also, we use Auhenicaion, Auhorizaion and Accouning () infrasrucure o auhenicae he and o receive s profiles securely. We shows performance of PL-P hrough comparison of packe loss during handover of, P and PL- P. The res of he paper is organized as follows. Secion 2 specifies P proocol as relaed works. -lossless P (PL-P) is proposed in Secion 3. Secion 4 presens analyical model and he numerical resuls. In Secion 5, we conclude his paper. 2. Relaed Works P is inended for providing nework-based IP mobiliy managemen suppor o a mobile node, wihou requiring he paricipaion of he in any IP mobiliy relaed signaling. The mobiliy eniies in he nework will rack he s movemens and will iniiae he mobiliy signaling and seup he required rouing sae. The core funcional eniies in he NETLMM infrasrucure are he Local Mobiliy Anchor (LMA) and he Mobile Access Gaeway (MAG). The LMA is responsible for mainaining he s reachabiliy sae and is he opological anchor poin for he s home nework prefix. The MAG is he eniy ha performs he mobiliy managemen on behalf of an and i resides on he access link where he is anchored. The MAG is responsible for deecing he s movemens o and from he access link and for iniiaing binding regisraions o he s LMA. Once a eners P domain and aaches o an access link, he MAG on ha access link, afer idenifying Layer2 Handoff is begun + PBU a n-mag Aached Aached Reques Response is begun Figure 2. Signaling flow of he proposed scheme (PL-P). he and acquiring is ideniy, will deermine if he is auhorized for he nework-based mobiliy managemen service. For updaing he LMA abou he curren locaion of he, he MAG sends a Proxy Binding Updae (PBU) message o he s LMA. Upon acceping his PBU message, he LMA sends a Proxy Binding Acknowledgemen () message including he s home nework prefix. I also creaes he Binding Cache enry and esablishes a bidirecional unnel o he MAG. The MAG on receiving he message ses up a bi-direcional unnel o he LMA and ses up he daa pah for he s raffic. A his poin he MAG will have all he required informaion for emulaing he s home link. I sends (RA) messages o he on he access link adverising he s home nework prefix as he hosed on-link-prefix. Figure 1 shows he signaling call flow for he s handover from previously aached MAG (pmag) o he newly aached MAG (nmag). Afer obaining he iniial address configuraion in he P domain, if he changes is poin of aachmen, he MAG on he previous link will deec he s deachmen from he link and will signal he LMA and will remove he binding and rouing sae for ha. However, he LMA upon acceping he reques will wai for cerain amoun of ime before i delees he binding, for allowing a smooh handover. The MAG on he new access link upon deecing he on is access link will signal he LMA for updaing he binding sae. Once ha signaling is complee, he will coninue o receive he RAs conaining is home nework prefix, making i believe i is sill on he same link and i will use he same address configuraion on he new access link. 3. Proposed Scheme (PL-P) In P, here are schemes o reduce handover laency and packe loss [4] [5]. Fas handovers for P is 48

3 Inerne Backbone LMA/HA Home Nework LMA Reques Response PBU nmag p-mag/ar n-mag/ar Figure 3. Sysem Model. pmag Aached link swiching Auh P Regisraion Handover Epoch RS/ RA Time a scheme ha only LMA exchange signaling wih MAGs o se up he fas handover [4]. However, his scheme does no follow he order of signaling flow in P. The scheme in [5] is he Exended PMA (EPMA) and LPMA funcionaliies o reduce signaling cos for inra domain handover and o opimize packe delivery [5]. However, his scheme does no preven packe loss during handover. In his paper, we propose -Lossless P (PL- P) wih auhenicaion, o reduce packe loss in P. PL-P follows he order of signaling flow in P and reduces packe loss. Figure 2 shows signaling flow of PL-P during handover. Afer he pmag is aware of he s deachmen, i sends he message o he LMA in P. In PL-P when pmag sends he message, he PBU message of nmag is included in message. Tha is, he pmag regisers on behalf of he nmag in advance o reduce handover laency. As a resul, he unnel beween he LMA and he nmag is esablished in advance. Also, when he nmag receives he message, i begins o buffer packes o he. Afer layer 2 handoff, he sends he RS message and receives he RA message including he s home nework prefix. In P, we use infrasrucure o auhenicae he like in [5]. Then, he nmag can receive he s profile securely using infrasrucure. 4. Performance Evaluaions We make a comparison of, P and PL- handover in erms of handover laency, coss and oal cos raio. For hose comparisons, we use a sysem model in Fig. 3. In he sysem model, we evaluae performance of hree schemes when an moves beween MAGs. We assume ha a corresponden node generaes daa packes desined o he a a mean rae λ, and he moves beween MAGs a a mean rae µ. We define packe o mobiliy raio (PMR, ρ) as he mean number of packes received by he from he corresponden per Toal Handover Laency Figure 4. Handover laency of P. movemen. When he movemen and packe generaion processes are independen and saionary, he PMR is given by ρ = λ/µ. We assume ha a cos for ransmiing a packe is dependen on he disance beween he sender and receiver. We define ha l d is he average lengh of a daa packe and l c is he average lengh of a conrol packe [7] Handover Laency In his secion, we analyze handover laency of, P and PL-P. To analyze handover laency of hree schemes, we define ha,mag, MAG,HN and MAG,MAG are ransfer delays beween an and an MAG, an MAG and a LMA, and adjacen wo MAGs, respecively. Handover laency consiss of hree laencies such as a link swiching laency, an IP conneciviy laency and a locaion updae laency. The link swiching laency is due o a layer 2 handoff. The IP conneciviy laency is due o movemen deecion and new IP address configuraion afer he layer 2 handoff. An can send or receive packes in nmag afer he IP conneciviy. We define handover laency of like as, TLaency = link swiching + Auh + + Addr Auoconf + Regisraion. (1) link swiching is a delay during layer 2 handover. Auh is a delay during auhenicaion of an hrough infrasrucure (2 (,MAG + MAG,HN )). Addr Auoconf is a delay during process of saeless auoconfiguraion (2,MAG ). Regisraion is a delay during binding updae o a HA (2 (,MAG + MAG,HN )). In Fig. 4, we define handover laency of P. Handover laency of P is following, T P Laency = link swiching + Auh + 49

4 LMA nmag pmag including PBU a nmag Forwarding Sar unneling Sar Aached Reques Response link swiching Auh RS/ RA Handover Epoch buffering Time delivery cos P PL P PMR(rho) Toal Handover Laency Figure 5. Handover laency of PL-P. Handover laency (ms) P PL P Wireless link delay (ms) Figure 6. Handover laency vs wireless link delay. + P Regisraion + RS RA. (2) P Regisraion is a delay during proxy binding updae o a LMA (2 MAG,HM ). RS RA is a delay during exchanging of a rouer soliciaion (RS) and a rouer adverisemen (RA) messages beween he and he MAG (2,MAG ). Handover laency of PL-P can be defined by formula 3 hrough Fig. 5. In his case, delay of proxy regisraion is reduced, since proxy regisraion is performed during layer 2 handoff. T PL P Laency = link swiching + Auh + + RS RA. (3) We presen some resuls based on he above analysis. Figure 6 shows handover laency of hree schemes. In Fig. 6, we use ha,mag =10ms, MAG,MAG =2ms, MAG,HN =10ms, referring o [8]. Figure 7. PMR vs packe delivery cos. Handover laency is seriously affeced by accesses of wireless link during handover. Hence, handover laencies of P and PL-P is lower han ha of. Also, PL-P reduces more handover laency han P, since he regisraion of nmag is performed during layer 2 handoff Toal Cos during Handover In his secion we analyze hree scheme in erms of oal cos. Toal cos consiss of signaling cos and packe delivery cos during handover. Signaling cos is cos of messages for signaling, and packe delivery cos is cos of packe ransferred from a HA. We assume ha signaling and delivery cos are influenced by ransmission delay. Tha is, signaling cos and delivery cos of a packe consis of an average lengh of signal and daa packe and ransmission delay, respecively. Followings are signaling cos of hree scheme. CSignaling = S Auh + S Addr Auoconf + + S Regisraion, (4) CSignaling P = S P Deregisraion + S Auh + + S P Regisraion + S RS RA, (5) C PL P Signaling = S P Deregisraion + S Auh + + S P Regisraion /2+S RS RA.(6) S Auh is cos for process of auhenicaion (l c Auh ). S Addr Auoconf is cos for saeless address auoconfiguraion (l c Addr Auoconf ). S Regisraion is cos for binding updae o a HA (l c Regisraion ). S P Regisraion is cos for proxy binding updae o a LMA (l c P Regisraion ). S RS RA is cos for exchanging a RS and a RA messages (l c RS RA ). We have known ha signaling coss of hree scheme differ lile. 50

5 Toal cos raio PL P / P PL P / PMR(rho) Figure 8. PMR vs oal cos raio. We assume ha delivery cos consiss of packe ransmission cos and packe los during handover. delivery coss of hree scheme are followings, CDelivery = λ d HN, TLaency η, (7) CDelivery P = λ d HN,pMAG TLaency P η, (8) PLP CDelivery = λ d HN, MAG,HN η + + λ d HN,nMAG buffering. (9) d HN, is delivery cos from home nework o a. d HN,pMAG is delivery cos from home nework o a pmag. d HN,nMAG is delivery cos from home nework o a new MAG hrough he pmag. In and PMIP, all packes sen from he CN are los during handover. However, in PL-P mos packes are unneled o nmag and are buffered. Figure 7 shows delivery coss of hree schemes. In Fig. 7 coss of P and PL-P are much lower han, since handover laencies are shor in P and PL-P. In addiion, cos of P is he lowes in hree schemes because packes from he CN are unneled and buffered in P. We calculae oal coss of hree schemes using above formulas. Then we calculae cos raio following formulas o compare performance of hree schemes. CosRaio PL P CosRaio PL P P = ToalCos PL P ToalCos (10) = ToalCos PL P ToalCos P (11) Figure 8 shows oal cos raios of and P abou PL-P. Through his figures we show ha PL- P reduces oal cos during handover. Tha is, PL- P enhances handover performance of 66% compared wih and 26% compared wih P. 5. Conclusions In P all packes from CNs are los during handover. To solve his problem, we have proposed PL- P. PL-P can preven packe loss during handover, since process of proxy regisraion is performed in advance and hen packes from CNs are unneled and buffered o nmag. Also, we used infrasrucure o auhenicae a and o receive s profiles securely. Hence, securiy of P is enhanced. We showed performance of PL-P hrough performance evaluaions. PL-P reduced 26% of oal cos compared wih P. This shows ha PL-P can enhance P hrough unneling and buffering. Recenly, P is in process of las call in IETF and will be a sandard documen. Then, if PL-P is used in addiion o P, P will be a more robus proocol in NETLMM working group of IETF. References [1] D. Johnson, C. Perkins, and J. Arkko, Mobiliy Suppor in IPv6, RFC 3775, IETF, June [2] S. Gundavelli, K. Leung, V. Devarapalli, K. Chowdhury, and B. Pail, Proxy Mobile IPv6, draf-iefnelmm-proxymip6-10.x, IETF, February [3] R. Koodli, Ed., Fas Handovers for Mobile IPv6, RFC 4068, IETF, July [4] P. Kim, S. Kim, and J. Jin, Fas Handovers for Proxy Mobile IPv6 wihou Iner-MAG Signaling, draf-pskim-nelmm-faspmip6-00.x, IETF, November [5] S. Park, N. Kang, and Y. Kim, Localized Proxy- wih Roue Opimizaion in IP-Based Neworks, IEICE TRANS. COMMUN., VOL.E90.B, NO.12, December [6] S. Ryu and Y. Mun, The Tenaive and Early Binding Updae for Mobile IPv6 Fas Handover, LNCS 3794, Springer, MSN 2005, December 2005, pp [7] R. Jain, T. Raleigh, C. Graff, and M. Bereschinsky, Mobile Inerne Access and QoS Guaranees using Mobile IP and RSVP wih Locaion Regisers, Proc. IEEE Inl. Conf. on Communicaions, IEEE, Alana, June 1998, pp [8] H. Fahi, R. Prasad, and S. Chakrabory, MO- BILITY MANAGEMENT FOR VOIP IN 3G SYS- TEMS: EVALUATION OF LOW-LATENCY HAND- OFF SCHEMES, IEEE Wireless Communicaions, Volume 56, Issue 1, January 2007, pp