Mobile IP mobility agent standby protocol
First Claim
1. In a standby Mobility Agent, a method of providing Mobile IP redundancy, the method comprising:
- determining that an active Mobility Agent, with which the standby Mobility Agent shares a virtual IP address known to a Mobile Node, is no longer acting as a Mobility Agent on a network segment for the Mobile Node;
assuming the role of active Mobility Agent on the network segment using the shared virtual IP address, thereby handling registrations from the Mobile Node; and
sending a list of registrations currently handled by the active Mobility Agent on the network segment to a new standby Mobility Agent on the network segment.
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Accused Products
Abstract
Disclosed is a method and apparatus for automatically backing up a Home Agent in Mobile IP. The method employs important components of the widely-used Hot Standby Router Protocol, but extends it to include synchronization of the mobility binding table between an active Home Agent and a standby Home Agent that backs it up. Also disclosed is a more general protocol for extending HSRP and related redundancy protocols to synchronize higher level functions other than mobility binding lists in Mobile IP (e.g., address translation tables in Network Address Translation (NAT), address bindings in Dynamic Host Configuration Protocol (DHCP) servers, dynamic ACL in Reflexive Access List, and TCP and GTP layer context in GPRS support nodes: SGSN & GGSN). Still other protocols that could benefit from HSRP include Lock and Key, Context-Based Access List, IP Security (IPSec), and H.323 gatekeeper.
677 Citations
31 Claims
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1. In a standby Mobility Agent, a method of providing Mobile IP redundancy, the method comprising:
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determining that an active Mobility Agent, with which the standby Mobility Agent shares a virtual IP address known to a Mobile Node, is no longer acting as a Mobility Agent on a network segment for the Mobile Node;
assuming the role of active Mobility Agent on the network segment using the shared virtual IP address, thereby handling registrations from the Mobile Node; and
sending a list of registrations currently handled by the active Mobility Agent on the network segment to a new standby Mobility Agent on the network segment. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. In an active Mobility Agent on a network segment, a method of maintaining Mobile IP operation, the method comprising:
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registering a Mobile Node;
creating a registration entry internally for the Mobile Node; and
sending a message notifying a standby Mobility Agent on the network segment of the registration, the active Mobility Agent and the standby Mobility Agent sharing a virtual IP address known to the Mobile Node. - View Dependent Claims (13, 14, 15, 16, 17, 18)
receiving a request from the standby Mobility Agent to dump registration entries for an entire mobility binding table, or a visitor table, containing multiple registration entries from the active Mobility Agent to the standby Mobility Agent; and
dumping the registration entries for the mobility binding table from the active Mobility Agent to the standby Mobility Agent.
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14. The method of claim 13, wherein dumping the registration entries mobility binding table is performed via UDP.
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15. The method of claim 12, wherein the UDP message notifying the standby Mobility Agent of the registration is unicast.
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16. The method of claim 12, further comprising periodically sending hello messages to the standby Mobility Agent, thereby notifying the standby Mobility Agent that the active Mobility Agent continues to function as the active Mobility Agent.
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17. The method of claim 12, further comprising periodically sending hello messages to a standby group of routers, each configured to act as an active Mobility Agent, thereby notifying the standby group that the active Mobility Agent continues to function as the active Mobility Agent.
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18. The method of claim 12, further comprising sending a resign message to the standby Mobility Agent before resigning the post of active Mobility Agent.
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19. A router supporting Mobile IP for use with a network segment having a plurality of routers and a plurality of Mobile Nodes which register with an active Mobility Agent from the plurality of routers, the router comprising:
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a memory;
a processor coupled to said memory;
one or more interfaces for sending and receiving data packets on a network, wherein said memory and said processor are adapted to provide (a) a primary router address and (b) a group virtual IP address which is adopted by the router when it becomes the active Mobility Agent of the network segment, and wherein said memory and said processor are adapted to (c) send registration updates to a standby Mobility Agent from among the plurality of routers. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28)
means for detecting when a hello message has not been received from the current active Mobility Agent within a predetermined time; and
means for automatically changing from the status of standby Mobility Agent to the status of active Mobility Agent when no hello message has been received from the current active router within said predetermined time.
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26. The router of claim 25, wherein the hello message includes a router priority, a router status, and the group virtual address.
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27. The router of claim 19, further comprising:
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means for automatically inserting the group virtual address into an address filter when the router assumes the status of active Mobility Agent; and
means for removing the group virtual address from the address filter when the router resigns the status of active Mobility Agent.
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28. The router of claim 19, wherein the active Mobility Agent is an active Home Agent and wherein the standby Mobility Agent is a standby Home Agent.
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29. In a router, a method of providing redundancy for a network segment, the method comprising:
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assuming the status of standby router on the network segment to backup an active router on the network segment, with which the standby router shares a virtual IP address known to a host based at the network segment;
determining that the active router is no longer acting as an active router for the host;
assuming the role of active router for the shared virtual IP address, thereby handling packet exchange tasks for the host; and
apprising a new standby router of an entry to a dynamic list specifying the status of one or more hosts based at the network segment. - View Dependent Claims (30, 31)
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Specification