Multiplex communications – Communication over free space – Having a plurality of contiguous regions served by...
Reexamination Certificate
2001-11-19
2004-04-13
Patel, Ajit (Department: 2664)
Multiplex communications
Communication over free space
Having a plurality of contiguous regions served by...
C370S352000, C370S432000
Reexamination Certificate
active
06721297
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to mobile networks, and, more particularly, to a method and apparatus for providing Internet Protocol (IP) mobility support for mobile networks.
BACKGROUND OF THE INVENTION
Many communication systems use Internet Protocol (IP) to transport packet data representative of voice, video, data or control traffic between endpoints (or “hosts” in IP terminology). In such systems, the data is divided into IP packets called datagrams that include addressing information (e.g., source and destination addresses) that enables various routers forming an IP network to route the packets to the specified destination. The destination address may comprise a unicast address identifying a particular host or a multicast address shared by a group of hosts. Typically, the hosts include various fixed devices and mobile wireless devices, often called mobile terminals, that are capable of roaming from site to site or even between different communication networks that use IP.
As wireless communication and mobile internet access have grown in popularity, it is envisioned that multiple IP-addressable devices will be carried within a car, airplane, train (or even on a person). Such a collection of devices is known as a mobile network and the IP-addressable devices residing within the mobile network are known as mobile network nodes. It would be desirable to provide for IP mobility of the mobile network, that is to maintain IP connectivity for the mobile network nodes as the mobile network moves from site to site or between different communication networks.
The most recent IP standard, Internet Protocol version 6, called “IPv6,” supports IP mobility for individual mobile nodes (presently defined in “draft-ietf-mobileip-ipv6-14.txt”) but does not address mobile networks. Generally, mobile IPv6 provides for a mobile node to move to different sites or networks without changing its IP address. A mobile node is always addressable by its “home” IP unicast address associated with a home site or network, regardless of the node's current point of attachment to the network infrastructure. While situated away from its home network, the mobile node is also associated with a unicast forwarding address (known as a “care of” address). The mobile node is addressable either directly by the care of address or indirectly by the home address. In the latter case, the IPv6 protocol causes packets addressed to the home address to be intercepted by a “home agent” and tunneled to the care of address in a manner known as triangular routing.
To that end, mobile IPv6 relies upon a mobile node recognizing when it is at a foreign site and, in such case, to inform its home agent of its new care of address. This is accomplished by a message termed a “binding update.” The mobile terminal may also send binding updates to various devices (termed “correspondent nodes”) prospectively corresponding with the mobile node, such that the correspondent nodes will use the new care of address rather than the home address to avoid triangular routing. Optionally, the binding updates may be “piggybacked” or embedded with other messages sent to the home agent or correspondent node.
One of the advantageous features of IPv6 is that it allows for mobility across homogenous media (termed “horizontal mobility”) as well as across heterogenous media (termed “vertical mobility”). Horizontal mobility may comprise, for example, movement from site to site within the same network (e.g., between two RF sites of a wireless wideband network). Vertical mobility may comprise, for example, movement between dissimilar access technologies (e.g., from wideband to wireless local area network (WLAN)).
A problem that arises (and the main reason why mobile IPv6 does not support mobile networks) is that the mobile network nodes are not necessarily capable of recognizing when they are at a foreign site or new access technology, such that they would be able obtain respective care of addresses and send binding updates. Indeed, it is preferred that most mobile network nodes, while attached to the mobile network, need not be aware of the movement of the mobile network from site to site or to new access technologies. Moreover, even if they were, it is preferred that most mobile network nodes will not send binding updates so as to prevent so called binding update “storms” that could result from multiple mobile network nodes simultaneously sending binding update messages through the network. As will be appreciated, binding update storms create network traffic overhead that can adversely affect handoff times and quality of service of the network.
Accordingly, a need has arisen to provide IP mobility support for mobile networks in a manner that builds upon the capabilities of mobile-IPv6, yet reduces or eliminates the number of binding updates that are required upon movements of the mobile network from site to site or between dissimilar access technologies. Advantageously, the IP mobility solution will allow for relatively fast and smooth vertical handoffs, as well as seamless horizontal mobility from site to site, without requiring the hosts of the mobile network to be aware of movement of the mobile network. The present invention is directed to satisfying these needs.
REFERENCES:
patent: 5910951 (1999-06-01), Pearce et al.
patent: 6198920 (2001-03-01), Doviak et al.
patent: 6230012 (2001-05-01), Willkie et al.
patent: 2001/0036834 (2001-11-01), Das et al.
patent: 2001/0046223 (2001-11-01), Malki et al.
patent: 2002/0012327 (2002-01-01), Okada
patent: 2002/0031107 (2002-03-01), Li et al.
patent: 2002/0080767 (2002-06-01), Lee
patent: 2002/0093943 (2002-07-01), Oliveira
patent: 2002/0193116 (2002-12-01), Agrawal et al.
patent: 2003/0063591 (2003-04-01), Leung et al.
David B. Johnson and Charles Perkins, Mobility Support in Ipv6, Internet Draft, Jul. 2, 2000, 122 pages, Nokia Research Center.
Ahmed Helmy, A Multicast-based Protocol for IP Mobility Support, 17 pages, Electrical Engineering Department, University of Southern California, helmy@ceng.usc.edu.
Soliman, Castelluccia, El-Malki, Bellier, Hierarchical MIPv6 Mobility Management (HMIPv6), Internet Draft, 07/01, 32 pages.
G. Dommety, A. Yegin, C. Perkins, G. Tsirtsie, K. El-Malki, M. Khalil, Fast Handovers for Mobile Ipv6, Internet Draft, 07/01, 69 pages, Working Group of the Internet Engineering Task Force (IETF).
T. Ernst, L. Bellier, A. Olivereau, C. Castelluccia, H. Lach, Mobile Networks Support in Mobile Ipv6 (Prefix Scope Binding Updates), Internet Draft, Jun. 22, 2001, 23 pages, Motorola Labs and INRIA Planete, France.
T. Ernst, C. Castelluccia and H. Lach, Extending Mobile-Ipv6 with Multicast to Support Mobile Networks Ipv6, 8 pages, Motorola Labs, Paris.
H. Chaskar, Requirements of a QoS Solution for Mobile IP, Internet Draft, Aug. 20, 2001, 8 pages, Nokia Research Center.
Korus Michael F.
Lewis Adam Cory
Hughes Terri S.
Motorola Inc.
Patel Ajit
Santema Steve R.
LandOfFree
Method and apparatus for providing IP mobility for mobile... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for providing IP mobility for mobile..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for providing IP mobility for mobile... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3266930