1. Field of the Invention
Aspects of the present invention relate to mobile IPv6 (MIPv6), and more particularly, to a method of applying fast MIPv6 (FMIPv6) to a mobile node while a mobile router performs a handover, and a mobile router and a mobile network therefor.
Aspects of the present invention also relate to a method of optimizing a neighbor discovery (ND) proxy-based route, and applying FMIPv6, for a mobile node in a mobile network.
2. Description of the Related Art
A technology of optimizing a route by using a neighbor discovery (ND) proxy delegates a network prefix for each mobile node (MN) in a mobile network by a mobile router (MR). Prefix delegation is a process of transferring a prefix to a mobile node in order to generate an IPv6 address. Each mobile node sets a Care of Address (CoA) from its delegated prefix in order to perform route optimization (RO).
In fast mobile IPv6 (FMIPv6), a CoA is generated and bound while a handover is performed at a link level. Various methods of applying FMIPv6 for a mobile router have been introduced. For example, Korean Laid-Open Patent Publication No. 10-2005-0039066 discloses a route optimization method for mobile nodes in an IPv6 mobile network on a basis of neighbor discovery proxy.
A mobile router (MR) can perform FMIPv6, thereby preventing packets from being lost by a corresponding node (CN). However, since a mobile node (MN) establishes communications via the MR, a handover does not occur at a link level, even if a mobile network is moved. Thus, packets transmitted to a previous CoA of the MN are likely to be lost while the MR performs the handover. Therefore, the MR must perform FMIPv6 during the handover. However, no technology has been available for a MR to undertake FMIPv6 in a mobile network node in order to prevent loss of packets.
Aspects of the present invention are designed to prevent loss of packets transmitted to a mobile node during a mobile router's handover. In particular, aspects of the present invention provide a method of applying FMIPv6 to a mobile node in order to prevent loss of packets transmitted to the mobile node during a mobile router's a handover, and a mobile router and a mobile network therefor. Aspects of the present invention also provide a computer readable medium having recorded thereon a computer program for the method of applying FMIPv6 to a mobile node.
Accordingly, aspects of the present invention provide a method that prevents loss of packets for an on-going session between MNNs and CNs when the MR undergoes handover, reduces hand-off latency for MNNs, requires no re-configuration or support of v6 routers, is interoperable with existing standards, and is simple and easily deployable.
According to an aspect of the present invention, there is provided a method of applying fast mobile IPv6 (FMIPv6) to a mobile node in a mobile network when a mobile router of the mobile network performs a handover from a first access router to a second access router, the method including: receiving, by the mobile router, a message from the first access router including a prefix corresponding to the second access router; transmitting, from the mobile router to the mobile node, a message including the prefix corresponding to the second access router and information indicating that the prefix is received from the first access router; transmitting, from the mobile router to the first access router, a message for FMIPv6; transmitting, from the mobile node to the first access router, a message for FMIPv6 when the mobile node receives the message including the information indicating that the prefix is received from the first access router; and transmitting, from the mobile router to the mobile node after the handover, a message to set a zero lifetime for a prefix corresponding to the first access router.
According to another aspect of the present invention, there is provided a mobile router of a mobile network in which fast mobile IPv6 (FMIPv6) is applied to a mobile node when the mobile router performs a handover from a first access router to a second access router, the mobile router including: a message receiving unit to receive, from the first access router, a message including a prefix corresponding to the second access router; and a message transmitting unit to transmit a message, to the mobile node, including the prefix corresponding to the second access router and information indicating that the prefix is received from the first access router, a message, to the first access router, for FMIPv6, and a message, to the mobile node after the handover, to set a zero lifetime for a prefix corresponding to the first access router, wherein the mobile node transmits a message for FMIPv6 to the first access router when the mobile node receives the message including the information indicating that the prefix is received from the first access router.
According to yet another aspect of the present invention, there is provided a mobile network in which fast mobile IPv6 (FMIPv6) is applied to a mobile node, the mobile network including: a mobile router to perform a handover from a first access router to a second access router, to receive, from the first access router, a message including a prefix corresponding to the second access router, to transmit, to the mobile node, a message including a prefix corresponding to the second access router and information indicating that the prefix is received from the first access router, to transmit, to the first access router, a message for FMIPv6, and to transmit, to the mobile node after the handover, a message to set a zero lifetime for a prefix corresponding to the first access router; and the mobile node to transmit, to the first access router, a message for FMIPv6 when the mobile node receives the message including the information indicating that the prefix is received from the first access router.
According to still another aspect of the present invention, there is provided a computer-readable medium having recorded thereon a computer program for a method of applying fast mobile IPv6 (FMIPv6) to a mobile node in a mobile network when a mobile router of the mobile network performs a handover from a first access router to a second access router, the method including: receiving, by the mobile router, a message from the first access router including a prefix corresponding to the second access router; transmitting, from the mobile router to the mobile node, a message including the prefix corresponding to the second access router and information indicating that the prefix is received from the first access router; transmitting, from the mobile router to the first access router, a message for FMIPv6; transmitting, from the mobile node to the first access router, a message for FMIPv6 when the mobile node receives the message including the information indicating that the prefix is received from the first access router; and transmitting, from the mobile router to the mobile node after the handover, a message to set a zero lifetime for a prefix corresponding to the first access router.
According to another aspect of the present invention, there is provided a mobile node applying fast mobile IPv6 (FMIPv6) in a mobile network when a mobile router of the mobile network performs a handover from a first access router to a second access router, the mobile node including: a message receiving unit to receive a message including a prefix corresponding to the second access router and information indicating that the prefix is received from the first access router; and a message transmitting unit to transmit a message for FMIPv6 to the first access router when the mobile node receives the message indicating that the prefix is received from the first access router, wherein the mobile router receives, from the first access router, a message including the prefix corresponding to the second access router, transmits, to the mobile node, the message including the prefix corresponding to the second access router and information indicating that the prefix is received from the first access router, transmits, to the first access router, a message for FMIPv6, and transmits to the mobile node after the handover a message to set a zero lifetime for a prefix corresponding to the first access router.
According to another aspect of the present invention, there is provided a method of applying fast mobile IPv6 (FMIPv6) to a mobile node in a mobile network when a mobile router of the mobile network performs a handover from a first access router to a second access router, the method including: receiving, by the mobile router, a message from the first access router including a prefix corresponding to the second access router; transmitting, from the mobile router to the mobile node, a message including the prefix corresponding to the second access router and an indication that FMIPv6 can be performed; transmitting, from the mobile router to the first access router, a message for FMIPv6; and transmitting, from the mobile node to the first access router, a message for FMIPv6 when the mobile node receives the message including the indication that FMIPv6 can be performed.
According to still another aspect of the present invention, there is provided a method of a mobile node applying fast mobile IPv6 (FMIPv6) in a mobile network when a mobile router of the mobile network performs a handover from a first access router to a second access router, the method including: receiving, from the mobile router, a message including a prefix corresponding to the second access router and information indicating that the prefix is received from the first access router; transmitting, to the first access router, a message for FMIPv6 after receiving the message including the information indicating that the prefix is received from the first access router; and receiving, from the mobile router after the handover, a message to set a zero lifetime for a prefix corresponding to the first access router.
According to yet another aspect of the present invention, there is provided a method of a mobile router of a mobile network applying fast mobile IPv6 (FMIPv6) to a mobile node in the mobile network when the mobile router performs a handover from a first access router to a second access router, the method including: receiving a message from the first access router including a prefix corresponding to the second access router; transmitting, to the mobile node, a message including the received prefix corresponding to the second access router and information indicating that the prefix is received from the first access router; transmitting, to the first access router, a message for FMIPv6; and transmitting, to the mobile node after the handover, a message to set a zero lifetime for a prefix corresponding to the first access router.
Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.
While Network Mobility (NEMO) is an emerging field, the Basic NEMO protocol doesn't include route optimization for mobile network nodes (MMN). Therefore, many solutions have been suggested for route optimization in NEMO. According to these route optimization techniques, however, the MNNs may loose packets in their on-going sessions when a mobile router (MR) undergoes a handover. This loss of packets is undesirable.
Accordingly, aspects of the present invention avoid a packet loss in an existing communication between an MNN and a corresponding node (CN) while an MR undergoes a handover. In particular, aspects of the present invention add a new flag in a prefix information option of a router advertisement (RA) message, and trigger Fast Mobile Internet Protocol version 6 (FMIPv6) messages by the MNNs without any actual handover occurring when the MMNs receive the prefix information with the new flag. The MR sends the new flag in the prefix information when the MR receives a proxy router advertisement (PrRtAdv). It is assumed that route optimization based on neighbor discovery (ND)-Proxy is working, and the MR, the MNNs and the access routers (R1 and R2 in
In accordance with Mobile Internet Protocol version 6 (MIPv6), a mobile internet protocol (IP) is generally used to maintain a connection of a transfer layer or an upper layer thereof to the Internet, even during movement of a terminal. In the case of a mobile network, an MR, and not a mobile terminal (hereinafter referred to as a mobile node (MN)), is a unit of movement, and a plurality of MNs may be present in a subnet of the MR. When an existing mobile IP is applied to a mobile network, there is no problem with transmission of data from a CN to the MR, but it is impossible to detect a route via which the data is transmitted to sub mobile nodes in the mobile network. MIPv6-based networking technology supports seamless networking of a communication terminal in a transportation unit (such as a bus, a train, or an airplane), which moves in group units, with the Internet.
A CN 130 connected to the Internet 102 accesses the home address HOA of the MN 110 to establish a communication with the MN 110 in the mobile network 106. The home address of the mobile network 106 to which the MN 110 belongs is bound as a Care of Address (CoA) of the MN 110 in a home agent HAMN 112 of the MN 110. Accordingly, the CN 130 transmits a data packet to the home address HOA of the mobile network 106 to which the MN 110 belongs.
In this case, when the mobile network 106 of a receiving node is not connected to the home network 104 but is connected to a location that is distant from the home network 104, the home agent MAMR 122 of the MR 124 encapsulates the data packet of the CN 130 into a packet having, as a target address, a CoA of the mobile router MR 124 controlling a prefix of the mobile network 106 of a target node (i.e., the MN 110), and transmits the data packet via a bi-directional tunnel between the home agent MAMR 122 and the MR 124.
When receiving the tunneled data packet, the MR 124 decapsulates the data packet, and transmits the decapsulated result to a link where the MN 110 is located. As illustrated in
To solve this problem, route optimization is performed with respect to an MN 110. Route optimization is a process in which the MN 110 provides its CoA to the home agent HAMN 112 of the MN 110 or the CN 130 so that a further communication can be established directly by using the CoA.
Binding is a process in which the MN 110 provides the home agent HAMN 112 (or the CN 130) with its CoA, and the home agent HAMN 122 (or the CN 130) matches the CoA with the home address HOA of the MN 110. Binding updating (BU) is a process in which the MN 110 having a new CoA provides the new CoA to the home agent HAMN 112 (or the CN 130), and the home agent HAMN 112 (or the CN 130) updates a previous CoA with the new CoA. After a BU is performed with respect to a home address and a CoA, a data packet is transmitted via an optimized route (as illustrated in
MIPv6 is a mobile protocol that further includes a neighbor discovery protocol, automatic address setting, and routing optimization, which are newly defined based on an MIPv4 concept related to a home agent (HA), a home network, an external network, a CoA, etc. In the neighbor discovery protocol, an MR acts as a neighbor discovery proxy.
After the handover, the MR 318 sends a zero lifetime setting for the earlier prefix (3ffa::/64) and delegates the new prefix (4ffa::/64). The MNN 320 and the VMN 322 will delete their previous CoAs (i.e., 3ffa::/64) and form new CoAs (i.e., 4ffa::/64) based on the new prefix.
Initially, the MNN 320 communicates with the CN 300 while moving with the MR 318. When the MR 318 undergoes a handover from R1 314 to R2 316, the MNN 320 receives a zero lifetime setting for the old prefix (3ffa::/64) and immediately receives a new prefix (4ffa::/64).
Since the MNN 320 undergoes no handover at the link-level, FMIPv6 is not triggered for MNN 320. Hence all packets destined to MNN's previous CoA (3ffa::3) are lost during the handover.
Valid Lifetime as shown in
According to aspects of the present invention, the ‘O’ flag is included as part of route optimization using ND-Proxy. The ‘O’ flag signifies that the corresponding prefix has been delegated by the MR 318, and the MNNs 320 should use this prefix for route optimization.
Referring to
The MR 318 and the MNN 320 start delivering packets using their respective new CoAs (derived from the prefix 4ffa::/64). Any packets destined to the MR's 318 or the MNN's 320 old CoAs (derived from 3ffa::/64) are tunneled by R1 314 to their new CoAs, respectively.
According to aspects of the present invention, the MR acts as an ND proxy to provide route optimization for an MN. Moreover, route optimization according to aspects of the present invention prevents a loss of packets for on-going sessions performed between an MN and a CN when a corresponding MR undergoes a handover, and further reduces a delay in a handover for the MN. Furthermore, aspects of the present invention do not require resetting or support from v6 routers. Accordingly, aspects of the present invention provide a route optimization method that is easy to implement and requires very minimal implementation changes to existing equipments.
The above-presented description is of the best mode contemplated for carrying out aspects of the present invention. The manner and process of making and using it is in such a full, clear, concise and exact terms as to enable to any person skilled in the art to which it pertains to make and use this invention. New embodiments in particular, which also lie within the scope of the invention can be created, in which different details of the different examples can in a purposeful way be combined with one another.
Aspects of the present invention are, however, susceptible to modifications and alternate constructions from that disclosed above which are fully equivalent. Consequently, it is not the intention to limit aspects of the present invention to the particular embodiment disclosed. On the contrary, the intention is to cover all modifications and alternate constructions coming within the spirit and scope of aspects of the present invention as generally expressed by the following claims which particularly point out and distinctly claim the subject matter of the invention.
Aspects of the present invention can be embodied as computer-readable code in a computer-readable medium (the computer may be any device having the information processing capability). The computer-readable medium may be any recording apparatus capable of storing data that is read by a computer system (e.g., a read-only memory (ROM), a random access memory (RAM), a compact disc (CD)-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc.). The computer-readable medium can be distributed among computer systems that are interconnected through a network, and aspects of the present invention may be stored and implemented as computer-readable code in the distributed system. Also, aspects of the present invention may be implemented in a carrier wave that transmits data via the Internet, for example.
Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.
Number | Date | Country | Kind |
---|---|---|---|
1068/CHE/2005 | Aug 2005 | IN | national |
This application is a National Stage of PCT International Patent Application No. PCT/KR2006/003084, filed Aug. 4, 2006, and claims the benefit of Indian Patent Application No. 1068/CHE/2005, filed Aug. 5, 2005, in the Indian Intellectual Property Office, the disclosures of which are incorporated herein by reference.
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/KR06/03084 | 8/4/2006 | WO | 00 | 9/10/2008 |