Network Working Group P. Kim Internet-Draft Korea Polytechnic University Intended status: Experimental H. Han Expires: August 24, 2009 KUT February 20, 2009 A Packet Distribution Scheme for Bandwidth Aggregation on Network Mobility draft-pskim-mext-multipath-distribution-00 Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on August 24, 2009. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Kim & Han Expires August 24, 2009 [Page 1] Internet-Draft Packet Distribution Scheme in NEMO February 2009 Abstract This draft considers a packet distribution scheme for bandwidth aggregation on the mobile network with a multi-interfaced mobile router (MMR). In the proposed scheme, the MMR with multiple heterogeneous wireless network interfaces effectively and fairly distributes packets over end-to-end multi-path through multiple network interfaces. Each network interface is considered to have a distribution counter associated with corresponding end-to-end path. This distribution counter varied by both weighted capacity and distributed packets is used to determine if a network interface has enough credits to distribute incoming packets on multiple paths. The capacity unit is shown to be a useful design parameter to make the performance of the proposed scheme as good as possible. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Proposed Scheme . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 Main Characteristics. . . . . . . . . . . . . . . . . . . . . 4 2.2 Example of Operation Procedure. . . . . . . . . . . . . . . . 5 2.3 Performance Indices and Useful Design Parameter . . . . . . . 6 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 4. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.1. Normative References . . . . . . . . . . . . . . . . . . 7 4.2. Informative References . . . . . . . . . . . . . . . . . 7 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8 1. Introduction In the near future, airplanes, automobiles, and even people will carry entire networks of IP devices that connect to the Internet, which is called a mobile network. To deal with the mobility support of mobile networks, the Network Mobility (NEMO) techniques have been developed[RFC5213][RFC4980][Erns2007][Chen2008]. In the NEMO, the mobile router (MR) is capable of changing its point of attachment to the Internet without disrupting higher layer connections of attached devices. Therefore, mobile nodes (MNs) inside a mobile network are unaware of their network's mobility; however, they are provided with uninterrupted Internet access even when the network changes its attachment point to the Internet. Meanwhile, to access the Internet, today's mobile computers often have more than one wireless interfaces such as WWAN(CDMA, GPRS), WMAN(WiBro, 802.16e), WLAN(802.11a/b/g), WPAN(802.15), etc[IEEE21] [Kass2008]. Once multiple network interfaces are offered, users may Kim & Han Expires August 24, 2009 [Page 2] Internet-Draft Packet Distribution Scheme in NEMO February 2009 want to select the most appropriate set of network interface(s) depending on the network environment, particularly in wireless networks which are mutable and less reliable than wired networks. Users may also want to combine a set of interfaces to get sufficient bandwidth or more bandwidth using bandwidth aggregation scheme in [Cheb2006]. The bandwidth aggregation scheme combines multiple network interfaces to provide end-to-end multi-path communication in order to improve quality or support demanding applications that need high bandwidth. In general, the bandwidth aggregation scheme consists of several schemes such as bandwidth estimation, packet distribution, packet reordering, etc. Among them, this draft focuses on the packet distribution scheme which effectively and fairly distributes packets on the appropriate end-to-end path through the corresponding network interface. The packet distribution scheme is categorized by priority-based and frame-based approaches. This draft considers the mobile network with the multi-interfaced mobile router (MMR) as shown in [RFC4980][Erns2007][Chen2008]. To consider the heterogeneous wireless network environment, the MMR can be assumed to have heterogeneous multiple wireless interfaces. Therefore, the MMR establishes multiple paths to the Internet through external wireless interfaces such as WMAN and WWAN with high mobility and wide coverage. However, due to bandwidth constraints of multi-path through external wireless interfaces, the MMR might require a bandwidth aggregation to get sufficient bandwidth for MNs' demanding inside a mobile network. Therefore, this draft considers a packet distribution scheme for bandwidth aggregation on the mobile network with the MMR. In the proposed scheme, the MMR with multiple heterogeneous wireless network interfaces effectively and fairly distributes packets over end-to-end multi-path through multiple network interfaces. Each network interface is considered to have a distribution counter associated with the corresponding end-to-end path. This distribution counter is used to determine if an interface has enough capacity to distribute a packet on the corresponding end-to-end path. The distribution counter can get capacity by the "weighted capacity" in bytes. This weighted capacity is computed by multiplication of the weight and the capacity unit. The weight is determined proportionately from the available bandwidth of the end-to-end path through the corresponding interface. The capacity unit in bytes is a useful design parameter and thus can affect on the performance of the proposed scheme. The weighed capacity is operated at the byte level and is added more to the distribution counter with higher weight than that with less weight. On the other hand, the distribution counter is also decreased by the size of packets being distributed. Thus, the distribution counter for each network interface is varied by distributed packets as well as Kim & Han Expires August 24, 2009 [Page 3] Internet-Draft Packet Distribution Scheme in NEMO February 2009 weighted capacity. In the proposed scheme, performance indices can be defined by ratio and amount of distributed packets, packet loss, and throughput, etc. As mentioned previously, the capacity unit is shown to be a useful design parameter to make the performance of the proposed scheme as good as possible. 2. Proposed Scheme This draft considers the mobile network where the MMR have multiple heterogeneous wireless network interfaces. The MMR establishes multiple communication paths to the Internet through external wireless interfaces such as WMAN and WWAN with high mobility and wide coverage. In this network environment, a packet distribution scheme is proposed for the bandwidth aggregation over end-to-end multi-path through multiple heterogeneous wireless interfaces. In the proposed scheme, the MMR distributes packets effectively and fairly on the appropriate end-to-end path through the corresponding network interface. 2.1 Main Characteristics In the proposed scheme, each network interface is considered to have a "distribution counter" associated with the corresponding end-to-end path. This distribution counter is used to determine if a path has enough credits to distribute incoming packets. The distribution counter can get credits by the "weighted capacity" in bytes. The weighted capacity is defined as follows: Weighted capacity = Capacity unit * Weight. The capacity unit in bytes is a useful design parameter and thus can affect on the performance of the proposed scheme. The weight is determined proportionately from the estimated available bandwidth of end-to-end paths. The weighed capacity is operated at the byte level and is added more to the path with higher weight than that with less weight. The distribution counter is also decreased by the size of packets being distributed. Thus, the distribution counter for each end-to-end path is varied by distributed packets as well as weighted capacity. 2.2 Operation Procedure and Example The operation procedure for each round is as follows. For the first path, packets are distributed when corresponding distribution counter is greater than the incoming packet's size. If it is lower, then the distribution counter is increased by the weighted capacity and the incoming packet is distributed on the current path. Kim & Han Expires August 24, 2009 [Page 4] Internet-Draft Packet Distribution Scheme in NEMO February 2009 Then the distribution counter is decreased by the size of packet being distributed. If the distribution counter is still lower than the incoming packet's size, the incoming packet held back until the proposed scheme moves on the next path. After visiting all paths, the round is finished. The above operation procedure in next round is repeated when there are incoming packets. As an example, the MMR is assumed to have heterogeneous three wireless network interfaces and thus there are three communication paths. These paths are called the Green (high b/w), Yellow (medium b/w), Red (low b/w) paths, respectively. Since this draft focuses on the packet distribution scheme for the bandwidth aggregation, available bandwidths for three paths through corresponding interfaces are assumed to have fixed weight ratio 4:2:1. The capacity unit is set by 256 bytes and thus these paths have weighted capacity 1024, 512, 256 bytes, respectively. Initially, all distribution counters for each path are set with 0. There are three kinds of session flows and they have four kinds of packet type with different sizes such as 256, 512, 768, 1024 bytes. Distribution counters for three paths are set by 0 at the initial time. - Incoming Packets at MMR Incoming packets are waiting to be distributed to the most appropriate path as following order: A(1024) <- D(256) <- B(768) <- C(512) <- B(768) - 1st Round At Green path, the weighted capacity is added and thus the distribution counter, DC(g), is 1024. Then, since the DC(g) is not less than the incoming packet's size (1024 bytes), the incoming packet 'A' is distributed to Green path and thus DC(g)=0. Currently, total amount of distributed packets to Green path, ADP(g), is 1024 bytes. At Yellow path, the weighted capacity is added and thus DC(y)=512. Then, since the DC(y) is not less than the incoming packet's size(256 bytes), the incoming packet 'D' is distributed to Yellow path and thus DC(y)=256. Currently, ADP(y)=256. At Red path, the weighted capacity is added and thus DC(r)=256. Then, since the DC(r) is still less than the incoming packet's size(768 bytes), move to Green path. Currently, ADP(r)=0. The 1st round is finished. - 2nd Round At Green path, since the DC(g) is less than the incoming packet's size(768 bytes), the weighted capacity is added and thus DC(g)=1024. Kim & Han Expires August 24, 2009 [Page 5] Internet-Draft Packet Distribution Scheme in NEMO February 2009 Then, since the DC(g) is not less than the incoming packet's size, the incoming packet 'B' is distributed to Green path and thus DC(g)=256. Currently, ADP(g)=1792. At Yellow path, since DC(y) is less than the incoming packet's size(512 bytes), the weighted capacity is added and thus DC(y)=768. Then, since the DC(y) is not less than the incoming packet's size, the incoming packet 'C' is distributed to Yellow path and thus DC(y)=256. Currently, ADP(y)=768. At Red path, since DC(r) is less than the incoming packet's size(768 bytes), the weighted capacity is added and thus DC(r)=512. Then, since the DC(r) is still less than the incoming packet's size, move to Green path. Currently, ADP(r)=0. The 2nd round is finished. The above operation procedure in next round is repeated when there are incoming packets. 2.3 Performance Indices and Useful Design Parameter There can be four performance indices in the proposed scheme as follows: . Ratio of Distributed Packets . Amount of Distributed Packets . Packet Loss . Throughput The ratio of distributed packets means that the proposed scheme should distribute packets fairly according to the weight ratio of each end-to-end path. The amount of distributed packets means that the proposed scheme should distribute packets as many as possible over each end-to-end path. The packet loss means that the proposed scheme should minimize lost packets on each end-to-end path. The throughput means that the proposed scheme should maximize the average rate of successful packet delivery on each end-to-end path. Of course, the throughput can be improved as many packets are distributed. However, the improvement of the throughput doesn't have the meaning if the performance for the packet loss is degraded. As mentioned before, the capacity unit is a useful design parameter to determine weighted capacity that affect on four performance indices. Too big value of the capacity unit can introduce excessive credits for end-to-end paths, which means that network paths have enough credits to distribute packets. Thus, incoming packets are more likely to be distributed simultaneously on every paths each round. Actually, this is not fair distribution according to weights for each network paths, which can thus degrade the performance for ratio of distributed packets. That is, since packets are distributed unfairly and too much over each end-to-end path, the performance for packet Kim & Han Expires August 24, 2009 [Page 6] Internet-Draft Packet Distribution Scheme in NEMO February 2009 loss can be degraded. Of course, since packets are distributed too much over each end-to-end path, the throughput can be improved. However, the improvement of the throughput doesn't have the meaning since the performance for the packet loss is degraded. On the other hand, too small value of the capacity unit can introduce deficient credits for end-to-end paths, which means that end-to-end paths don't have enough credits to distribute packets. Thus, incoming packets are less likely to be distributed on every paths each round, which can thus degrade the performance for the amount of distributed packets. Since the amount of distributed packets over each end-to-end path is small, the performance for the throughput can be degraded whereas the performance for the packet loss can be improved. Thus, the important issue here can be how to choose an appropriate capacity unit to make the performance of the proposed scheme as good as possible. 3. IANA Considerations This document has no IANA actions. 4. References 4.1. Normative References [RFC5213] Devarapalli, V., Wakikawa, R., Petrescu, A., Thubert, P., "Network Mobility (NEMO) Basic Support", IETF RFC 3963, Jan 2005. [RFC4980] Ng, C. et al., "Analysis of multihoming in network mobility support", RFC4980. October, 2007. 4.2. Informative References [Erns2007] Ernst, T. et al., "Motivations and Scenarios for Using Multiple Interfaces and Global Addresses", draft-ietf-monami6-multihoming-motivation-scenario-02.txt., July, 2007. [Chen2008] Chen, X., Zhou, H., Qin, Y., Zhang, H., "Multi-interfaced mobile router scheme and enhanced path selection algorithm", International Conference on Telecommunications, 2008(ICT 2008), pp. 1~8, June 2008. Kim & Han Expires August 24, 2009 [Page 7] Internet-Draft Packet Distribution Scheme in NEMO February 2009 [IEEE21] IEEE802.21/D09.00, "Draft standard for local and metropolitan area networks : Media indendent handover services", Feb 2008. [Kass2008] M. Kassar, B. Kervella, G. Pujolle, "An overview of vertical handover decision strategies in heterogeneous wireless networks", Computer Communications, 31(10), pp. 2607~2620, 2008. [Cheb2006] Chebrolu, K., and Rao, R., "Bandwidth Aggregation for Real-Time Applications in Heterogeneous Wireless Networks", IEEE Trans. on Mobile Computing, Vol. 5, No. 4, pp. 388-403, 2006. Author's Address Pyungsoo Kim Department of Electronics Engineering, Korea Polytechnic University, 2121 Jungwang-Dong, Shiheung City, Gyeonggi-Do 429-793 KOREA Phone: +82 31 8041 0489 EMail: pskim@kpu.ac.kr Youn-Hee Han KUT Gajeon-Ri, 307, Byeongcheon-Myeon Cheonan, Chungnam KOREA Phone: +82 41 560 1486 Email: yhhan@kut.ac.kr Kim & Han Expires August 24, 2009 [Page 8]