as) United States
`a2) Patent Application Publication co) Pub. No.: US 2004/0190534 Al
`(43) Pub. Date: Sep. 30, 2004
`
`Adrangietal.
`
`US 20040190534A1
`
`(54) METHOD, APPARATUS AND SYSTEM FOR
`ENSURING RELIABLE ACCESS TO A
`ROAMING MOBILE NODE
`
`(76)
`
`Inventors: Farid Adrangi, Lake Oswego, OR
`(US); Ranjit S. Narjala, Hillsboro, OR
`(US); Michael Andrews, Beaverton,
`OR (US)
`
`Correspondence Address:
`BLAKELY SOKOLOFF TAYLOR & ZAFMAN
`12400 WILSHIRE BOULEVARD
`SEVENTH FLOOR
`LOS ANGELES, CA 90025-1030 (US)
`
`(21) Appl. No.:
`
`10/401,896
`
`(22)
`
`Filed:
`
`Mar. 28, 2003
`
`Publication Classification
`
`(SL)
`
`Inte C17 oacccccssscssesssssssssnssnstntnasveenee HO4L. 12/56
`
`(52) U.S. Ch ee eeseeneees 370/400; 370/338; 370/252
`
`(57)
`
`ABSTRACT
`
`A method, apparatus and system provide reliable access to
`a mobile node. Requests for care of addresses (COAs) are
`intercepted and the mobile node hostnamesin the requests
`are replaced with alternative configured names. These
`altered requests are then passed down the network stack.
`Similarly, replies to the COA requests are also intercepted
`and the alternative configured names may be replaced with
`the mobile node hostnames. These replies may then be
`passed up the network stack. A mobile IP registration request
`extension may be used to create a mapping entry in a
`Domain Name Services (DNS) server between the mobile
`node hostname and the mobile node home address. This
`
`mapping entry ensures that the mobile node is consistently
`reachable via its hostname.
`
`BEGIN
`
`
`
`INTERCEPT COA
`REQUEST OR
`REPLY
`
`
`
`
`401
`
`COA REPLY
`
`
`
`
`
`
`REPLACE THE CONFIGURED
`ALTERNATIVE NAME WITH
`
`THE HOSTNAME
`
`
`404
`406
`
`PASS THE PACKET DOWN
`TO THE LOWER LAYER
`
`PASS THE PACKET UP TO
`THE ABOVE LAYER
`
`-
`
`407
`
`“| MAP ENTRYIN
`DNS SERVER
`
`oe
`
`Google Exhibit 1039
`Google v. VirtaMove
`
`aN 402
`COA REQUEST a a
`_ 7 COA REQUEST
`|
`“OR REPLY? _-~Ne
`| 403
`
`
`
`
`REPLACE THE HOSTNAME
`WITH A CONFIGURED
`
`
`ALTERNATIVE NAME
`
`
`
`405
`
`Google Exhibit 1039
`Google v. VirtaMove
`
`

`

`Patent Application Publication Sep. 30,2004 Sheet 1 of 4
`
`US 2004/0190534 A1
`
`ART)
`
`
`
`CORPORATEINTRANET
`
`

`

`Patent Application Publication Sep. 30,2004 Sheet 2 of 4
`
`US 2004/0190534 A1
`
`le Co-Located|Non-Colocated|StaticNA s=
`
`
`Hosinarne
`Hlastnarne
`inl One
`
` Scenario|NAI
`Assignment
`
`
`
`
`
`
`Address
`
`

`

`Patent Application Publication Sep. 30,2004 Sheet 3 of 4
`
`US 2004/0190534 A1
`
`TCP/IP LAYER 304
`
`
`
`_ MIP DATA LAYER 303
`
`CONFIGURATION
`MODULE 305
`
`PHYSICAL LAYER 301
`
`
`
`LINK LAYER302
`
`
`
`FIG. 3
`
`

`

`Patent Application Publication Sep. 30,2004 Sheet 4 of 4
`
`US 2004/0190534 A1
`
`BEGIN
`
`
`
`
`
`INTERCEPT COA
`REQUEST OR
`REPLY
`
`402
`
`401
`
`COA REPLY
`
`COA REQUEST
`
`COA REQUEST
`OR REPLY?
`.
`
`a“
`
`403
`.
`405
`
`REPLACE THE HOSTNAME
`REPLACE THE CONFIGURED
`WITH A CONFIGURED
`ALTERNATIVE NAME WITH
`ALTERNATIVE NAME
`THE HOSTNAME
`
`
`| | 404
`| 406
`
`
`
`PASS THE PACKET DOWN
`TO THE LOWER LAYER
`
`
`PASS THE PACKET UP TO
`THE ABOVE LAYER
`
`
`DNS SERVER
`
`MAP ENTRYIN
`
`FIG. 4
`
`

`

`US 2004/0190534 Al
`
`Sep. 30, 2004
`
`METHOD, APPARATUS AND SYSTEM FOR
`ENSURING RELIABLE ACCESS TO A ROAMING
`MOBILE NODE
`
`FIELD OF THE INVENTION
`
`[0001] The present invention relates to the field of mobile
`computing, and, more particularly to a method, apparatus
`and system for ensuring reliable access to a roaming mobile
`node.
`
`BACKGROUND OF THE INVENTION
`
`[0002] A hostname is a unique name by which a comput-
`ing device may be identified on a network. Hostnames are
`used to simplify access to computing devices by enabling
`users to use unique names instead of addresses to access
`these devices. A hostname is typically translated into an
`Internet address by a Domain Name System (DNS) server.
`
`[0003] Use of hostnames in mobile computing environ-
`ments has introduced additional considerations. As mobile
`computing devices
`(hereafter mobile nodes) become
`increasingly popular, various protocols have been developed
`to address mobile computing requirements. For example, to
`enable mobile node users to move from one location to
`another (roam) while continuing to maintain their connec-
`tivity to the same network, the Internet Engineering Task
`Force (IETF) has promulgated roaming standards (Mobile
`IPv4, IETF RFC 3344, August 2002, hereafter Mobile IPv4,
`and Mobile IPv6, IETF Mobile IPv6, Internet Draft draft-
`ietf-mobileip-ipv6-19.txt.
`(Work In Progress), October
`2002, hereafter Mobile IPv6).
`
`[0004] Mobile IPv4 is currently the predominantstandard,
`and many networks today are Mobile IPv4 compliant.
`Mobile IPv4 introduced the concept of Network Access
`Identifiers (NAIs). NAIs may be used in either Mobile IPv4
`or Mobile IPv6 compliant networks to uniquely identify a
`mobile node. While a mobile nodeis typically identified by
`one hostname, it may also be associated with more than one
`NAI. Similar to hostnames, NAIs mayalsobe translated into
`an Internet address by a DNSserver.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`invention is illustrated by way of
`[0005] The present
`example and not limitation in the figures of the accompa-
`nying drawings in which like references indicate similar
`elements, and in which:
`
`FIG.1 illustrates a known corporate intranet struc-
`[0006]
`ture today;
`
`FIG.2 is a table illustrating the various ways in
`[0007]
`which MN 140 may be configured;
`
`[0008] FIG. 3 illustrates a Mobile IP network stack
`according to embodiments of the present invention; and
`
`FIG.4 is a flow chart illustrating an embodiment
`[0009]
`of the present invention.
`
`DETAILED DESCRIPTION
`
`[0010] Embodiments of the present invention provide a
`method, apparatus and system for reliably accessing a roam-
`ing mobile node. Reference in the specification to one
`embodiment or an embodiment of the present invention
`means that a particular feature, structure or characteristic
`
`described in connection with the embodimentis included in
`at least one embodimentof the present invention. Thus, the
`phrases in one embodiment, according to one embodiment
`or the like appearing in various places throughout
`the
`specification are not necessarily all referring to the same
`embodiment.
`
`[0011] FIG. 1 illustrates a known corporate intranet (
`Corporate Intranet 100) structure. Corporate Intranet 100
`may include both wired and wireless networks and may
`comprise multiple subnets. Subnets refer to portions of
`networks that may share the same common address format.
`For example, on a Transport Control Protocol/Internet Pro-
`tocol (TCP/IP) network, all subnets may use the samefirst
`three sets of numbers (such as 100.10.10).
`[0012] As previously described, a mobile node (hereafter
`MN 140) may have a hostname and a NAI associated with
`it. Mobile nodes that conform to Mobile IPv4 and/or Mobile
`IPv6 standards (hereafter collectively referred to as Mobile
`IP Standards) today may roam freely across subnets within
`Corporate Intranet 100. When MN 140 exits its home
`subnet,
`it may continue to maintain its current transport
`connections and constant reachability in one of two ways.In
`the first scenario, MN 140 mayregister with a home agent
`(HA 130) whenit exits its home subnet. During the regis-
`tration process, MN 140 informs HA 130 of MN 140 s
`care-of address (hereafter COA), namely MN 140s address
`on its new subnet. HA 130 thereafter intercepts all IP packets
`addressed to MN 140 and reroutes the packets to MN 140s
`COA.As MN 140 moves from one subnet to another, MN
`140 may obtain new COAs via Dynamic Host Configuration
`Protocol (DHCP)or other similar protocols. To ensure that
`HA 130 is able to properly route packets to MN 140, MN
`140 must continuously update HA 130 with its new COA as
`it roams on Corporate Intranet 100. This configuration is
`commonly referred to as a co-located communications
`mode.
`
`[0013] Alternatively, in Mobile IPv4 compliant networks,
`when MN 140 leaves its home subnet, it may register with
`HA 130 via a foreign agent (FA 135) on MN 140 s new
`(foreign) subnet. By registering with FA 135, MN 140 may
`use FA 135 s IP address as its COA whenregistering with
`HA 130. In this scenario, HA 130 continues to interceptall
`packets addressed to MN 140, but these packets are now
`rerouted to FA 135, namely MN 140s COA as provided to
`HA 130. FA 135 examinesall packets it receives, and sends
`the appropriate ones to MN 140atits current location on the
`foreign subnet. This configuration is commonly referred to
`as a non co-located communications mode. The decision of
`whether to use co-located or non co-located mode is well
`knownto those of ordinary skill in the art. Certain networks
`may, for example, force MN 140 to register with FA 135 in
`order to maintain its transport connections. In other net-
`works, MN 140 may havethe option of registering with FA
`135 or operating in a co-located mode.
`[0014]
`In summary, when MN 140 is roaming across
`subnets, it may have associated with it: (i) a hostname;(ii)
`a NAI; (iii) an invariant home address; and (iv) a COA. As
`will be readily apparent to those of ordinary skill in the art,
`these multiple identifiers for MN 140 may cause inconsis-
`tencies as MN 1490roams. Details of these inconsistencies
`are described below.
`
`[0015] FIG.2 is a table illustrating the various ways in
`which MN 140 may be configured to conform to Mobile
`
`

`

`US 2004/0190534 Al
`
`Sep. 30, 2004
`
`same as the hostname, regardless of the fact there is no
`the mobile node may be
`IPv4 standards. As illustrated,
`mapping for the hostname, MN 140 will nonetheless be
`configured according to one of six scenarios. In Scenario 1,
`reachable. In other words, a CN that attempts to reach MN
`MN 140 in a co-located mode may be assigned a NAI that
`is different from its hostname. When MN 140 obtains its
`140 using its hostname will enter the same name as MN 140
`COA (e.g., via DHCPor other similar protocols), a mapping
`s NAI, which will be resolved in the DNS server to MN_H.
`entry may be created in a DNSserver, mapping the COAto
`[0019]
`In Scenario 5, MN 140 in a co-located mode may
`MN 140 s hostname {Hostname, COA}. This COA may
`be assigned a static home address (e.g., by a corporate IT
`change continuously as MN 140 roams across subnets.
`department), and a mapping mayalsobe created in the DNS
`Additionally, MN 140 may be configured to obtain its home
`server {Hostname, MN_H}. As MN 140 roamsandobtains
`address through a NAI extensioninits registration request to
`a COA, however, a second entry may also be created in the
`HA 130. HA 130 mayissue a home address to MN 140 from
`DNSserver {Hostname, COA}. The two mappings for MN
`HA 130sIP address pool or by requesting the home address
`140 s hostname result in an IP address contention for the
`from a DHCPserver via a DHCP(orother similar protocol)
`request. In the latter instance,
`in response to HA 130 s
`request, the DHCP server may issue MN 140 a home address
`and send the DNSserver an update to create a mapping entry
`in the DNS server {NAI, MN_H}. As previously described,
`a correspondent node (CN) may attempt to reach MN 140
`using its NAI and/or hostname. In Scenario 1 above, how-
`ever,
`if CN tries to access MN 140 using MN 140 s
`hostname, instead of being resolved to MN 140 s home
`address, the hostname is resolved to MN 140 s COA.Since
`this communication is not routed via HA 130 that is respon-
`sible for maintaining MN 140 s mobile connectivity, MN
`140 maynot be reached reliably via its hostname.
`
`hostname. More specifically, the second mapping for host-
`name may overwrite thefirst, leaving the {Hostname, COA}
`mapping in the DNSserver. As a result, as described in
`Scenario 1 above, MN 140 may no longer be reachable
`reliably using its hostname because the hostname may be
`mapped to MN 140 s COA.
`[0020]
`In the final scenario, Scenario 6, MN 140 in a non
`co-located mode may be assigned a static home address,
`resulting in a mapping entry in the DNSserver for {Host-
`name, MN_H}. As is readily apparent to those of ordinary
`skill in the art, this scenario presents no problems because,
`in a non co-located mode, no other mapping entry is created
`for MN 140 in the DNSserver. CN maytherefore reach MN
`140 reliably via its hostname.
`[0021]
`Insummary, Scenarios 1, 2, 3 and 5 aboveresult in
`various accessibility problems for MN 140 while it roams
`from subnet to subnet. Embodiments of the present inven-
`tion resolve these problemsby using a configured alternative
`name. More specifically, in embodiments of the invention,
`DHCPrequests for COAs from MN 140 andreplies to such
`requests are intercepted within MN 140 and replaced with
`configured alternative names and hostnamesrespectively.
`This eliminates a hostname mapping to COAs in the DNS
`server, thus eliminating the problems described above. This
`concept of using a configured alternative name is described
`in further detail below, in relation to FIG. 3.
`
`[0022] FIG. 3 illustrates a Mobile IP network stack on
`MN140 according to embodiments of the present invention.
`The concepts of network stacks and passing messages up
`and down network stacks are well known to those of
`ordinary skill in the art and further description thereof is
`omitted herein in order not to unnecessarily obscure the
`present invention. As illustrated, the mobile IP layer (MIP
`Data Layer 303) intercepts DHCP requests that are sent by
`MN140 to acquire a COA (hereafter referred to as COA
`Requests). Instead of directly routing the request down the
`network stack (i.e., to Link Layer 302 and Physical Layer
`301), however, according to one embodimentof the present
`invention, Configuration Module 305(illustrated conceptu-
`ally as being contained within MIP Data Layer 303) may
`replace MN 140 s hostname in the COA request with a
`configured alternative name. This configured alternative
`name may then be passed down the network stack to Link
`Layer 302 and Physical Layer 301. In one embodiment, the
`COArequest is a DHCP request and a DHCP server may
`process the request and send back a DHCPreply with a COA
`assignment (hereafter referred to as COA Reply). Upon
`receipt of this COA Reply, Configuration Module 305 may
`replace the configured alternative name in the reply with the
`actual hostname, and pass the COA Reply up the network
`stack, to TCP/IP Layer 304.
`
`In Scenario 2, Mobile Node 140 in a non co-located
`[0016]
`mode may be assigned a NAI that is different from its
`hostname. MN 140 may again be configured to obtain its
`home address through a NAI registration, resulting in a
`mapping entry in the DNS server {NAI, MN_H}. In this non
`co-located scenario, however, MN 140 may use FA 135 s
`address as its COA when registering with HA 130. Thus,
`unlike Scenario 1, MN 140 does not acquire a COA, which
`would result in a mapping between the hostname and the
`COA in the DNSserver. As a result, there may not be a
`mapping entry at all for MN 140s hostname in the DNS
`server, and CN may not reach MN 140via its hostname. In
`addition, although this scenario doesnottrigger a mapping
`entry for MN 140s hostname in the DNS Server, the DNS
`Server may nonetheless still include a stale entry in its
`binding table (e.g., MN 140 s hostname maystill be mapped
`to an old COA from a previous configuration).
`In this
`situation, when CN that attempts to reach MN 140 via its
`hostname, the hostname will be resolved in the DNS Server
`to the stale COA,resulting in CN not being able to reach MN
`140.
`
`[0017] According to Scenario 3, MN 140 in a co-located
`mode may be assigned a NAI
`that
`is the same as its
`hostname. As described above in Scenario 1, the DNS server
`may include mappings for {NAI, MN H} and {Hostname,
`COA}. In this situation, however, since the NAI and host-
`name are the same, the mapping in the DNSserver may be
`unpredictable due to an IP address contention between MN
`140 s hostname and NAI. The mappings may override each
`other, given the order in which the mappingsare entered into
`the DNSserver. As a result, access to MN 140 via either its
`hostname or NAI is likely to be unpredictable, at best.
`
`In Scenario 4, MN 140 in a non co-located modeis
`[0018]
`assigned a NAI that
`is the same as its hostname. This
`scenario does not
`introduce any problems because, as
`described in Scenario 2 above, the NAI is mapped in the
`DNSserver to MN 140 s invariant home address {NAI,
`MN_H}. In this situation, however, since the NAI is the
`
`

`

`US 2004/0190534 Al
`
`Sep. 30, 2004
`
`[0023] As will be readily apparent to those of ordinary
`skill in the art, by intercepting and modifying the COA
`Requests and COA Replies according to the embodiments
`described above, MN 140 s hostname may no longer be
`mapped to its COA in the DNSserver. Therefore, in order to
`ensure that there is some mapping for MN 140 s hostname
`in the DNSserver, in one embodiment of the present
`invention, a new registration request extension (Hostname
`Extension) may be used. Hostname Extension may be cre-
`ated per the guidelines specified in the Mobile IPv4 stan-
`dard, and may be configured to inform HA 130 to request
`creation of a mapping entry between MN 140 s hostname
`and MN s homeaddress in the DNS server {Hostname,
`MN_H}. In this manner, HA 130 may ensure that MN 140
`s hostname is consistently mapped to MN 140 s home
`address in the DNS server. MN 140s NAI continues to be
`mapped to MN 140s homeaddress {NAI, MN_H}. Accord-
`ing to one embodiment of the present invention, these two
`mappings enable MN 140 to be reachable via both its
`hostname and NAI, regardless of whether the hostname and
`the NAI are the same.
`
`FIG.4 is a flow chart illustrating an embodiment
`[0024]
`of the present invention. Although the following operations
`may be described as a sequential process, many of the
`operations may in fact be performed in parallel or concur-
`rently.
`In addition,
`the order of the operations may be
`re-arranged without departing from the spirit of embodi-
`ments of the invention. In 401, a COA Request or COA
`Reply may beintercepted. The request and/or reply may be
`examined in 402. In the case of a COA Request, the mobile
`node hostname in the request may be replaced by a config-
`ured alternative name in 403 and passed down the network
`stack in 404. Alternatively, in the case of a COA Reply, in
`405 the configured alternative name maybe replaced by the
`mobile node hostname and the reply may be passed up the
`network stack in 406. Additionally, at any point prior to,
`during or after these events, the mobile node s homeagent
`may request creation of a mapping entry in the DNSserver
`in 407, mapping the mobile node s hostname to the mobile
`node s home address.
`
`[0025] The mobile nodes, homeagents and foreign agents
`according to embodiments of the present invention may be
`implemented on a variety of data processing devices.It will
`be readily apparent to those of ordinary skill in theart that
`these data processing devices may include various software,
`and may comprise any devices capable of supporting mobile
`networks, including but not limited to mainframes, work-
`stations, personal computers,
`laptops, portable handheld
`computers, PDAs and/or cellular telephones. In an embodi-
`ment, mobile nodes may comprise portable data processing
`systems such as laptops, handheld computing devices, per-
`sonal digital assistants and/or cellular telephones. According
`to one embodiment, home agents and/or foreign agents may
`comprise data processing devices such as personal comput-
`ers, workstations and/or mainframe computers. In alternate
`embodiments, home agents and foreign agents may also
`comprise portable data processing systems similar to those
`used to implement mobile nodes.
`
`[0026] According to embodimentofthe present invention,
`data processing devices may include various components
`capable of executing instructions to accomplish an embodi-
`ment of the present invention. For example, the data pro-
`cessing devices may include and/or be coupled to at least
`
`one machine-accessible medium. As used in this specifica-
`tion, a machine includes, but is not limited to, any data
`processing device with one or more processors. As used in
`this specification, a machine-accessible medium includes
`any mechanism that stores and/or transmits information in
`any form accessible by a data processing device,
`the
`machine-accessible medium including but not limited to,
`recordable/non-recordable media
`(such
`as
`read only
`memory (ROM), random access memory (RAM), magnetic
`disk storage media, optical storage media and flash memory
`devices), as well as electrical, optical, acoustical or other
`form of propagated signals (such as carrier waves, infrared
`signals and digital signals).
`
`[0027] According to an embodiment, a data processing
`device may include various other well-known components
`such as one or more processors. The processor(s) and
`machine-accessible media may be communicatively coupled
`using a bridge/memory controller, and the processor may be
`capable of executing instructions stored in the machine-
`accessible media. The bridge/memory controller may be
`coupled to a graphics controller, and the graphics controller
`may control the output of display data on a display device.
`The bridge/memory controller may be coupled to one or
`more buses. A host bus host controller such as a Universal
`Serial Bus (USB) host controller may be coupled to the
`bus(es) and a plurality of devices may be coupled to the
`USB. For example, user input devices such as a keyboard
`and mouse maybe includedin the data processing device for
`providing input data.
`
`In the foregoing specification, the invention has
`[0028]
`been described with reference to specific exemplary embodi-
`ments thereof. It will, however, be appreciated that various
`modifications and changes may be made thereto without
`departing from the broaderspirit and scope of embodiments
`of the invention, as set forth in the appended claims. The
`specification and drawings are, accordingly, to be regarded
`in anillustrative rather than a restrictive sense.
`
`Whatis claimedis:
`
`1. Amethod for ensuring reliable access to a mobile node,
`comprising:
`
`intercepting a a care of address (COA) request, the COA
`request including a mobile node hostname;
`
`replacing the mobile node hostname in the COA request
`with an alternative configured name; and
`
`transmitting the COA request with the alternative config-
`ured nameto a server.
`
`2. The method according to claim 1 further comprising:
`
`intercepting a COA reply from the server, the COA reply
`including the alternative configured name;
`
`replacing the alternative configured name with the mobile
`node hostname; and
`
`transmitting the COA reply with the mobile node
`hostname to the mobile node.
`3. The method according to claim 2 further comprising
`transmitting a registration request to map an entry for the
`mobile node hostname and the mobile node home address in
`a Domain Name Services (DNS)server.
`4. The method according to claim 3 wherein transmitting
`the registration request comprises transmitting a Mobile IP
`registration request with a hostname extension.
`
`

`

`US 2004/0190534 Al
`
`Sep. 30, 2004
`
`5. The method according to claim 1 wherein the server
`comprises a dynamic host control protocol (DHCP) server
`and the COA request includes a DHCP request.
`6. Asystem for ensuring reliable access to a mobile node,
`comprising:
`
`a mobile node capable of transmitting a care of address
`(COA) request, the COA request including a mobile
`node hostname;
`
`a configuration module capable of intercepting the COA
`request and replacing the mobile node hostname with
`an alternative configured name, the configuration mod-
`ule further capable of retransmitting the COA request;
`and
`
`a server capable of receiving the COA request.
`7. The system according to claim 6 wherein the serveris
`further capable of responding to the COA request and
`transmitting a COA reply to the mobile node wherein the
`reply includes the alternative configured name.
`8. The system according to claim 7 wherein the configu-
`ration module is further capable of intercepting the COA
`reply and replacing the alternative configured name with the
`mobile node hostname, the configuration module addition-
`ally capable of transmitting the COA reply with the mobile
`node hostname to the mobile node.
`
`9. The system according to claim 6 further comprising a
`Domain Name Services (DNS) server capable of mapping
`an entry for the mobile node hostname and the mobile node
`home address.
`
`10. The system according to claim 6 wherein the server
`comprises a dynamic host control protocol (DHCP) server,
`and the COA request comprises a DHCP request.
`11. The system according to claim 6 wherein the mobile
`node includes the configuration module.
`12. Asystem for ensuring reliable access to a mobile node,
`comprising:
`
`a mobile node capable of transmitting a care of address
`(COA) request, the COA request including a mobile
`node hostname; and
`
`a configuration module capable of intercepting the COA
`request and replacing the mobile node hostname with
`an alternative configured name, the configuration mod-
`ule further capable of retransmitting the COA request to
`a server.
`
`13. The system according to claim 12 wherein the con-
`figuration module is capable of intercepting a COA reply
`from the server wherein the COA reply includesthe alter-
`native configured name, the configuration module further
`capable of replacing the alternative configured name with
`the mobile node hostname, the configuration module addi-
`tionally capable of transmitting the COA reply with the
`mobile node hostname to the mobile node.
`
`14. The system according to claim 12 wherein the server
`comprises a dynamic host control protocol (DHCP) server,
`and the COA request comprises a DHCP request.
`
`15. The system according to claim 12 wherein the mobile
`node includes the configuration module.
`16. An apparatus for ensuring reliable access to a mobile
`node, comprising:
`
`a configuration module capable of intercepting a care of
`address (COA) request from the mobile node wherein
`the COA request includes a mobile node hostname,the
`configuration module further capable of replacing the
`mobile node hostname with an alternative configured
`name and retransmitting the COA request.
`17. The apparatus according to claim 16 wherein the
`configuration module is capable of intercepting a COAreply,
`and wherein the COA reply includesthe alternative config-
`ured name,
`the configuration module further capable of
`replacing the alternative configured name with the mobile
`node hostname,
`the configuration module additionally
`capable of retransmitting the COA reply with the mobile
`node hostname to the mobile node.
`
`18. An article comprising a machine-accessible medium
`having stored thereon instructions that, when executed by a
`machine, cause the machine to:
`
`intercept a care of address (COA)request from the mobile
`node, the COA request including a mobile node host-
`name;
`
`replace the mobile node hostname with an alternative
`configured name; and
`
`transmit the COA request with the alternative configured
`name to a server.
`
`19. The article according to claim 18 wherein the instruc-
`tions, when executed by the machine, further cause the
`machineto:
`
`intercept a COA reply from the server wherein the reply
`COAincludes the alternative configured name;
`
`replace the alternative configured name with the mobile
`node hostname; and
`
`transmit the COA reply with the mobile node hostnameto
`the mobile node.
`
`20. The article according to claim 19 wherein the instruc-
`tions, when executed by the machine, further cause the
`machineto transmit a registration request to map an entry for
`the mobile node hostname and the mobile node home
`address in a Domain Name Services (DNS)server.
`21. The article according to claim 20 wherein the instruc-
`tions, when executed by the machine, further cause the
`machine to transmit a Mobile IP registration request with a
`hostname extension.
`
`22. The article according to claim 19 wherein the server
`comprises a dynamic host control protocol (DHCP) server
`and the COA request includes a DHCP request.
`
`*
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