JP2894443B2 - Mobile packet routing system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ATM (Asy)
nchronous Transfer Mode) L
The present invention relates to a mobile packet routing system for realizing the movement of a terminal on an AN (Local Area Network).

[0002]

2. Description of the Related Art On a LAN constructed by Ethernet (registered trademark), an Internet Protocol (IP) is used.
ocol) in order to guarantee communication when a terminal having an address moves across subnets.
ternet Engineering Task F
orce) at MOBILE IP (RFC200
2. RFC: Request For Comment
t) has been proposed.

[0003] In MOBILE IP, there are two types of mobile terminals: a fixed IP address (home address) that is constant regardless of movement, and a variable IP address (care-of address) assigned by the network when moving between subnets. And the home agent existing in the home subnet manages the correspondence between the two addresses. When an IP packet is transmitted from another terminal to the mobile terminal by designating a fixed IP address, the IP packet is delivered to the destination mobile terminal via the home agent.

[0004] This MOBILE IP is transferred to an ATM LAN.
In order to realize the above, first, a MAC (Media Access Controller) of Ethernet over ATMLAN is used.
ol) LAN that emulates communication below the sublayer
E (LAN EMULATION) is activated and this L
The MOBILE IP may be operated on the ANE.

However, the upper application uses the same one used in the conventional LAN as it is, and furthermore, it is assumed that the interface between LANE and this higher application is the same as the interface of the existing LAN. Due to this LANE specification, A
TM-specific QoS (Quality of Service)
ce) (the use of this QoS guarantee function requires an interface different from the existing LAN interface).

[0006] In addition, MOBILE IP is transferred to ATM LA.
N is another method for realizing communication on the IP layer and below.
IP over ATM emulating on TM environment
Then, when transferring data across subnets, IP o
According to the specification of the ver ATM, it is indispensable to pass through a router, but there is a problem in that passing through this router causes a delay due to processing such as analysis of an IP address.

In the MOBILE IP specification, packet transfer from another terminal to a mobile terminal is not performed directly, but is always relayed through a home agent. Therefore, a packet must pass through a redundant path. Therefore, there is a problem of a redundant path that increases the communication delay.

[0008] On the other hand, the Internet draft Support for Mobile NHRP
Device in ATM Network (dr
aft-horikawa-mobile-nhrp-
00. txt) is used to solve the problem of the QoS guarantee specific to the ATM and the problem of the processing delay by the router.
RP (Next Hop Resolution Pr)
, and extends the NHRP specification to support the movement of ATM hosts. This N
HRP is a function that enables communication over an end-to-end ATM connection without passing through a router in communication across subnets.

FIG. 18 shows a conventional Mobile NHR.
A showing an example of a network to which P Device is applied
FIG. 2 is a configuration diagram of a TM network. In FIG. 18, reference numeral 1 denotes an ATM network including a plurality of IP subnets (hereinafter, referred to as LIS); 14, a mobile terminal (hereinafter, referred to as a mobile ATM host) on which an NHC (Next Hop Client), which is an NHRP client, is mounted;
To 93 are NHS (Ne) prepared for the IP subnet.
xt Hop Server).

Next, a conventional Mobile shown in FIG.
The operation of the ATM network to which NHRP Device is applied will be described. As shown in FIG.
If the host 14 moves from the home LIS to a different LIS, the ATM host 14 will automatically assign (by hardware) an A
The NHS of the LIS in which it is located by associating the TM address with its own fixed IP address (NHS 93 in the example in the figure)
Attempt to register.

If the fixed IP address is out of the control of the NHS 93, the NHS 93 uses ordinary routing information to transfer the registration information to the NHS 91 in charge of the IP address.
(Located in a different LIS). This allows
The correspondence information between the ATM address of the ATM host 14 and the fixed IP address is registered in the NHS 91.

According to the above configuration, the other ATM host has the A
To obtain the ATM address of the TM host 14,
The other ATM host uses the IP address of the fixed IP address.
It is sufficient to always inquire the NHS 91 existing in the subnet by designating the fixed IP address of the ATM host 14, and the other ATM host can obtain the ATM address resolved by this inquiry.
Using the address to the target ATM host 14
P packets can be sent.

[0013] This Support for Mobile
e NHRP Device in ATM Network
rk (draft-horikawa-mobile-
nhrp-00. txt) is assumed to be MOBILE
It is assumed that an ATM host moves with only one fixed IP address without using IP. And
In the case of communication across subnets, in order to obtain the ATM address of the other party, a method of sequentially listening around from the server on the closer subnet is adopted.

[0014] This Support for Mobile
e NHRP Device in ATM Network
rk (draft-horikawa-mobile-
nhrp-00. txt) does not allow a router to intervene in the system. When a mobile ATM host communicates at a destination, when a router enters the communication partner, a subnet violation that the mobile ATM host has an IP address including a network number inconsistent with a destination network number managed by the router. Is caused. For this reason, it is an essential condition that the router is always short-cut by the NHRP mechanism and communication is performed using only the ATM address.

[0015]

SUMMARY OF THE INVENTION As described above, LA
When operating MOBILE IP on NE, LAN
There is a problem that the QoS specific to ATM becomes completely invisible due to the specification of E. In addition, IP over AT
When MOBILE IP is operated on M, there is a problem of processing delay due to passing through a router.

Also, due to the specification of MOBILE IP, there is a problem of a redundant path due to home agent relay.

[0017] Support for Mobile
le NHRP Device in ATM Net
In the plan shown in the work, it is not allowed to provide a router in the ATM network and perform communication via the router. However, due to the operation of the network,
In many cases, routers are indispensable due to security requirements and the like, and there is a problem that this scheme cannot cope with an actual network. MOBILE
Since IP is not used, there is also a problem that complete mobility transparency such as movement during communication cannot be supported.

The present invention has been made in order to solve the above-mentioned problems. In an actual network in which a router is interposed, it is possible to support the movement of an ATM host and control the QoS guarantee specific to the ATM from an application. It is intended to realize a simple mobile packet routing system.

It is another object of the present invention to realize a mobile packet routing system in which a router and a home agent are short-circuited while preventing the occurrence of redundant paths and the processing delay can be minimized while guaranteeing QoS specific to ATM. .

[0020]

According to a first aspect of the present invention, there is provided a mobile packet routing system, wherein an ATM network comprises an ATM switch provided between an ATM switch and a subnet.
M router, an ATM host which is a mobile terminal moving across subnets, and a destination ATM based on an IP address.
ATM A that resolves and outputs the ATM address of the host
An RP server, and a home agent existing in the subnet of the home of the ATM host.
Based on the specifications of the over ATM, an ATMARP server prepared for each of the subnets manages the correspondence between the ATM address and the IP address of the ATM router or the ATM host existing in the subnet, and
A system in which a home agent prepared for each subnet manages the correspondence between a fixed IP address of an ATM host homed on this subnet and a variable IP address assigned when moving between subnets, based on the specification of EIP (RFC2002). Configuration, ATM
When the host moves between subnets and registers (/ cancels) the correspondence between the newly acquired IP address and its own fixed IP address in the home agent, the home agent sets the fixed IP address and The above-mentioned ATM AR is used for association with its own ATM address.
A function for registering (/ cancelling) with the P server is provided.
When the M host moves to a subnet other than the home, an IP packet indicating the fixed IP address of the ATM host is transferred to the ATM host via the home agent.

Further, the mobile packet routing system according to the second aspect of the present invention provides an ATM ARP server with a fixed IP address.
When an address is registered or unregistered, the ATM ARP server associates all the ATM hosts on the same subnet with the fixed IP address in the cache and the corresponding ATM address. Request that the table be cleared.

Further, the mobile packet routing system according to the third aspect of the present invention provides an ATM ARP server with a fixed IP address.
At the time the address is registered, the ATM ARP server requests all ATM hosts on the same subnet to update the ATM address corresponding to the fixed IP address in the cache to that of the home agent. Is what you do.

Further, the mobile packet routing system according to the fourth invention is characterized in that the ATM ARP server has a broadcast server function so that the ATM ARP server has a broadcast server function.
A request to clear or update the cache is sent to all ATM hosts managed by the server at the same time.

Further, the mobile packet routing system according to the fifth invention has an MCS in an ATM network in accordance with the MARS specification, and provides a cache via a standard MCS to all ATM hosts managed by an ATM ARP server. The clear or update request is notified all at once.

Further, the mobile packet routing system according to the sixth invention is characterized in that the ATM network is an ATM switch, an ATM router provided between subnets, an ATM host which is a mobile terminal moving across subnets,
The NHS is composed of a home agent existing in the subnet of the home of the ATM host, and the NHRP (Ne)
xt Hop Resolution Protocol
NHS prepared for each subnet based on the specification of l)
Manages the correspondence between ATM addresses and IP addresses of ATM routers and ATM hosts existing in the subnet,
A mobile packet routing system in which a home agent prepared for each subnet manages a correspondence relationship between a fixed IP address of an ATM host having the subnet as a home and a variable IP address assigned when moving between subnets, based on the specification of OBILE IP. At
When the ATM host moves across subnets and registers (or releases) the correspondence between the newly acquired IP address and its own fixed IP address in the home agent, the home agent and the fixed IP address and its own ATM address With the function of registering (or canceling) the association with the NHS, and indicating the fixed IP address of the ATM host when the ATM host moves to a subnet other than the home.
The P packet is transferred to the ATM host via the home agent and not via the ATM router.

Further, the mobile packet routing system according to the seventh aspect of the present invention is characterized in that when a fixed IP address is registered in the NHS or when the registration is released, the NHS and all other ATM hosts existing on the ATM network and other It requests the NHS to clear the correspondence table between the fixed IP address existing in the cache and the ATM address.

In the mobile packet routing system according to the eighth invention, when the fixed IP address is registered in the NHS, the NHS is stored in the cache with respect to all ATM hosts and other NHSs existing on the ATM network. ATM corresponding to the existing fixed IP address
Requests that the address be updated to that of the home agent.

Further, the mobile packet routing system according to the ninth invention is characterized in that the ATM network is an ATM switch, an ATM router provided between subnets, an ATM host which is a mobile terminal moving across subnets,
The correspondence between the ATM address and the IP address of an ATM router or an ATM host, which is composed of an NHS and a home agent existing on the subnet of the home of the ATM host and has an NHS prepared for each subnet based on the NHRP specification. MOBILE
Based on the IP specification, the home agent prepared for each subnet has the home agent A
In a mobile packet routing system for managing the correspondence between a fixed IP address of a TM host and a variable IP address assigned when moving between subnets, an address resolution function for converting the fixed IP address registered by the home agent into a variable IP address. And a trigger setting function for instructing the NHS to make (or not make) this address translation request upon receipt of registration (/ cancellation) of a fixed / variable IP address from the ATM host. , When the target is a fixed IP address triggered by the home agent, the NHS is
Requests the home agent to convert the address, obtains the converted variable IP address, and targets
An IP address indicating a fixed IP address of the ATM host when the ATM host moves to a subnet other than the home when the ATM host moves to a subnet other than the home.
The packet is transferred directly to the ATM host without passing through the home agent and the ATM router.

In the mobile packet routing system according to the tenth aspect, a flow for address resolution is partially omitted by integrating the NHS and the home agent.

Further, the mobile packet routing system according to the eleventh aspect of the present invention provides a mobile packet routing system in which the NHS requests the home agent to set a trigger for a fixed IP address, or releases the trigger setting.
S requests all ATM hosts and other NHSs existing on the ATM network to clear the correspondence table between the fixed IP address existing in the cache and the ATM address.

Further, the mobile packet routing system according to the twelfth aspect of the present invention provides a mobile packet routing system in which the NHS requests the home agent to set a trigger on a fixed IP address, or releases the trigger setting.
Is to update the ATM address corresponding to the fixed IP address existing in the cache to that of the ATM host for all ATM hosts and other NHSs existing on the ATM network.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a network configuration diagram showing an embodiment of a mobile packet routing system according to the present invention. In FIG. 1, 1 is an ATM network composed of a plurality of IP subnets (LIS), 2 is an ATM router connecting the IP subnets, and 3 is an IP over.
ATM ARP (Add
less Resolution Protocol)
A mobile ATM host on which a client and a MOBILE IP client are mounted, and 41 and 42 are ATM ARP servers prepared for IP subnets.

Reference numeral 5 denotes a fixed IP address of the mobile ATM host 3.
A home agent that manages the correspondence between addresses and variable IP addresses. This home agent 5 is IP
At the time of receiving the address registration request, the designated fixed IP address is associated with its own ATM address, and the home ATM
It has a function of registering in the ARP server 41. Reference numeral 6 denotes a fixed ATM host.

FIG. 2 is a sequence diagram showing a registration procedure when the mobile ATM host 3 moves to an IP subnet other than the home and an operation sequence when communicating with the fixed ATM host 6 in the network configuration shown in FIG. It is. Next, the operation of the mobile packet routing system shown in FIG. 1 will be described with reference to FIG. When the ATM host 3 receives a packet from the home subnet LIS-A,
Upon moving to the P subnet LIS-B, the ATM host 3 first sends the LIS to the ATM
-B is automatically assigned, and furthermore, DHCP (Dynamic Host Config) is used.
(variable protocol) by a function such as a protocol (uration protocol).
P address).

Next, the A implemented in the ATM host 3
The TM ARP client transmits the variable IP address (the IP address in LIS-B in the example of this figure) and the ATM address (the ATM address in LIS-B in the example of this figure) of the ATM host 3 in the procedure of IPover ATM. The correspondence is registered in the ATM ARP server 42. Also, A
The MOBILE IP client mounted on the TM host 3 uses the MOBILE IP procedure to change the variable IP address (in this example, the IP address in LIS-B).
And a fixed IP address (IP address in LIS-A in the example of this figure) previously held by the ATM host 3;
Is registered in the home agent 5 existing in the home subnet LIS-A. Until here, IP ove
r It uses the ATM and MOBILE IP protocols themselves.

The LIS-A home agent 5 having received the registration request sends the fixed IP address of the designated ATM host 3.
Address (IP address in LIS-A in the example of this figure) and own ATM address (LIS-A in the example of this figure).
ATM address in A) and LIS-A A
Register in the TM ARP server 41. This registration is MOB
Although it is outside the rules of ILE IP, the registration protocol is IP
Over The ATM itself is used. At this point, the data shown in FIGS. 3 and 4 is stored in the ATM ARP server 41 and the home agent 5.

The mobile ATM host 3 is a fixed ATM host 6
When transmitting an IP packet to the ATM, the ATM host 3 first specifies the IP address of the ATM host 6 and changes the ATM address of the ATM host 6 to the ATM of the LIS-B to which the ATM has moved.
The ARP server 42 is inquired. Next, when the ATM host 3 receives the resolved ATM address of the ATM host 6 from the ARP server 42, the ATM host 6
To the ATM host 6 using the ATM address of
Set the TM connection. Then, an IP packet is transmitted to the ATM host 6 using this connection.

The fixed ATM host 6 is replaced by the mobile ATM host 3.
When sending an IP packet to the ATM host 3, the fixed IP address of the ATM host 3 is set to a different subnet (LIS-A in this example).
Therefore, the fixed ATM host 6 first uses its own AIS, the ATM ARP server 42, to send the A
The ATM address obtained by resolving the ATM address of the TM router 2
ATM router 2 using the ATM address of M router 2
An ATM connection is set up between this and.

Next, the IP packet is transferred to the fixed ATM host 6.
Is transferred from the ATM router 2 to the ATM router 2, the ATM router 2 uses the fixed IP address of the ATM host 3 (in this example, the IP address in LIS-A) as a key to perform the ATM A
The RP server 41 is used to resolve the ATM address (in this example, the ATM address in LIS-A). In this case, from the data shown in FIG.
The TM address (in this example, the ATM address in LIS-A) is returned to the ATM router 2, and the ATM router 2 sets up an ATM connection with the home agent 5 using the ATM address of the home agent 5.

When the IP packet is transferred from the ATM router 2 to the home agent 5, MOBIL
In accordance with the rules of the EIP, the address information is replaced with the variable IP address of the ATM host 3 based on the data shown in FIG. 4, and transmission to this address starts again. This IP packet is transferred from the home agent 5 to the ATM host 3 via the ATM router 2 using a similar address resolution procedure.

According to the present embodiment, the mobile packet routing apparatus uses IP over ATM and MOBIL
The cooperative operation of the EIP has an effect that the movement of the ATM host across the subnet can be realized, and the QoS control specific to the ATM can be performed from the application.

Embodiment 2 ATM ARP server 4
The data managed by 1 and 42 changes on-time as the ATM host 3 moves. In general, ATM AR
The data in the P servers 41 and 42 is cached in the ATM ARP client, and this data is
It is not updated on-time when the M host 3 moves. This information is checked every few minutes according to the IP over ATM standard, and old data is automatically deleted. Therefore, if the ATM host moves during this period, the contents of the caching and the data of the ATM ARP servers 41 and 42 may be inconsistent. This causes a problem that another ATM ARP client that has once cached cannot communicate with the ATM host that has moved.

To solve this problem, the ATM AR
When the data contents are updated, the P servers 41 and 42 broadcast a cache clear message to all ATM hosts managed by themselves. FIG. 5 is a sequence diagram showing a cache clear operation when an ATM host is moved according to another embodiment of the present invention.
Next, a cache clear operation by the ATM ARP server will be described with reference to FIG. When the ATM host 3 moves, the home agent 5 sends the ATM ARP server 41
, The fixed IP address of the ATM host 3 and the ATM address of the home agent itself are registered.

At this time, when the ATM ARP server 41 recognizes the update of data related to a certain IP address, it broadcasts a cache clear message to all the managed ATM hosts. The ATM host receiving this message clears the data of the IP address.

FIG. 6 shows a format example of the cache clear message. This is the same as the format of the ATM ARP Request message specified by IP over ATM, but extends its meaning. That is, the ATM ARP client sends the IP address field (Target protocol)
address) and an ATM address (Targ)
et ATM number & Subaddres
If s) receives a null ATM ARP Request message, it means to invalidate the ATM address cache of this IP address.

When the ATM host wants to communicate with the destination ATM host, it recognizes that there is no correspondence table between the IP address and the ATM address in the cache of the ATM host itself, and the ATM ARP server sends the ATM host of the communication partner.
Get the ATM address of the host.

According to this embodiment, when the ATM host moves, the local cache of the other host is cleared, so that the ATM host whose cache has been cleared always obtains the ATM address of the moved other host from the ATM ARP server. become. For this reason, there is an effect that error-free communication can be secured.

Embodiment 3 FIG. 7 is a network configuration diagram showing another embodiment of the mobile packet routing system according to the present invention. The network shows an application of the mobile packet routing system shown in the first embodiment, and the movement of the ATM host 3. It shows the behavior of time. 7, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. 7 is MARS (Multi Cas)
t Address Resolution Serv
er) MCS (Mul) with multicast function
tiCast Server). In addition, MARS
About InternetDraft: Support
for Multicast over UNI3.
1 based ATM Networks.

In the second embodiment, the function of broadcasting the cache clear message is a function of the ATM ARP servers 41 and 42. Therefore, the broadcasting is performed not on each ATM host in parallel but on a sequential basis. In 3, the parallel processing type broadcast function of the MCS 7 is added to the ATM ARP server 4.
1, 42 are used. In this case, ATM A
The RP server 41 sends the cache clear message to the MCS.
7, the message is broadcast to all ATM hosts on this subnet, under the responsibility of MCS7. This mechanism and protocol may use the MARS specification itself.

According to this embodiment, since the MARS specification dedicated to broadcast is used, there is an effect that the speed of broadcast can be increased.

Embodiment 4 FIG. In the fourth embodiment, A
At the timing when the TM ARP server recognizes the update of the ATM address related to the IP address, a cache update message is broadcast using the same system as in FIGS. 5 and 7 so that the cache has a correct value. The ATM host receiving this message updates the ATM address corresponding to the IP address.

The same format example as that of FIG. 6 is used as the format example of the cache update message. However, AT
The MARP client checks the IP address field (Target protocol address).
And ATM address (Target ATM num
AT where ber & Subaddress is specified
When the M ARP Request message is received, it means to update the ATM address cache of this IP address.

According to this embodiment, when the ATM host moves, the local cache of another host is updated with the new information, so that the I-communication performed at the time of new communication with the mobile terminal is performed.
This has the effect of omitting P address resolution and shortening the time until communication is established.

Embodiment 5 FIG. In the fifth embodiment, NHRP and MOBIL are used in order to implement a router shortcut.
This is to operate in cooperation with the EIP. FIG. 8 is an ATM network configuration diagram showing an ATM network configuration in another embodiment of the mobile packet routing system according to the present invention. 8, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. Reference numeral 8 denotes a mobile ATM host mounted with NHC and MOBILEIP clients, which are NHRP clients. Reference numerals 91 and 92 denote NHRP servers NHS prepared for IP subnets.

This NHS has a function of broadcasting a cache clear message to all ATM hosts under management and adjacent NHSs when data contents are updated as in the second embodiment. Reference numeral 10 denotes a home agent, which receives a registration request for an IP address,
It has a function of registering the designated fixed IP address in the NHS 91 in association with its own ATM address.
Otherwise, it is completely the same as FIG.

FIG. 9 is a sequence diagram showing a registration procedure when the mobile ATM host 8 moves to an IP subnet other than its own home and a sequence when communicating with the fixed ATM host 6 in the mobile packet routing system shown in FIG. FIG. When the ATM host 8 moves to an IP subnet other than the home, first, the ATM host 8 is assigned an ATM address and a variable IP address as in the first embodiment. Next, the NHC of the ATM host 8 is
The correspondence between the variable IP address and the ATM address is registered in the NHS 92 in the NHRP procedure. Further, the MOBILE IP client of the ATM host 8 registers the correspondence between the variable IP address and the fixed IP address of the ATM host in the home agent 10. Up to this point, NHRP and M
It is the protocol of OBILE IP itself.

Home agent 1 that has received the registration request
0 associates the designated fixed IP address with its own ATM address and registers it in the NHS 91. This registration is out of the specification of MOBILE IP, but the registration protocol uses the NHRP specification itself. At this point, NH
In S91 and S92, the data shown in FIGS. The data of the home agent 10 is the same as in FIG.

At this time, when the NHS 91 recognizes the update of the data related to a certain IP address, it broadcasts a cache clear message to all the managed ATM hosts and adjacent NHSs. The ATM host and the NHS receiving this message send the IP
Clear the data at the address. This mechanism is defined in the NHRP standard, and the NHRP Purge Req
west message.

When the ATM host 8 sends an IP packet to the ATM host 6, the ATM host 8 first queries the NHS 92 for the IP address of the ATM host 6, and sets up an ATM connection using this ATM address. Then, using this connection, the ATM host 6
To send an IP packet. When the ATM host 6 transmits an IP packet to the ATM host 8, the ATM host 6 makes an inquiry to the NHS 92.
The address has not been registered, and the inquiry message is transferred to the NHS 91 in the normal NHRP procedure.
From here, the ATM address is returned.

However, this ATM address is that of the home agent 10 from FIG. 10, and the ATM connection with the home agent 10 is set by a shortcut without going through a router. When the IP packet is transferred to the home agent 10, MOBILE
The address information is replaced from the data of FIG. 4 to the variable IP address of the ATM host 8 according to the rules of IP, and transmission to this address starts again. This IP packet is NHR
It is transferred to the ATM host 8 by a shortcut using the P address resolution procedure.

This mechanism can release the ATM-specific QoS control to the application by using the NHRP, and can establish a short-cut path without passing through a router. However, whether or not to establish a shortcut path end-to-end depends on the policy of the network administrator, and in some cases, a router is interposed.

According to this embodiment, NHRP and MO
By operating BILE IP in cooperation, ATM hosts can be moved across subnets, and ATM
Specific QoS control is also possible from the application,
In addition, there is an effect that processing delay due to passing through a router is eliminated.

Embodiment 6 FIG. In the sixth embodiment, instead of broadcasting a cache clear message, a cache update message is broadcast. In particular, at the timing when the NHS recognizes the update of the ATM address related to the IP address, it broadcasts the cache update message. The ATM host receiving this message sends the ATM corresponding to the IP address.
Update the address. FIG. 12 shows a format example of the cache update message.

This is the NHRP R defined by NHRP.
The format is the same as that of the registration request message, but its meaning is extended.
The NHC and NHS are in the IP address field (Cl
ient ProtocolAddress) and A
TM address (Client NBMA Addresses)
s & Subaddress) specified NHRP
AddressRegistration Req
When an est message is received, it means to update the ATM address cache of this IP address.

According to this embodiment, when the ATM host moves, the local cache of the other host is updated with the new information, so that the IP address resolution performed at the time of new communication with the mobile terminal is omitted, and until the communication is established. This has the effect of shortening the time for

Embodiment 7 In the seventh embodiment, in order to realize a shortcut between a router and a home agent, the position of the MOBILE IP home agent is extended to the position of an address resolution server, and is operated in cooperation with NHRP. FIG. 13 is a network configuration diagram showing an ATM network configuration in another embodiment of the mobile packet routing system according to the present invention. 13, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. Reference numeral 11 denotes a mobile ATM host on which an NHC and a MOBILE IP extended client are mounted.
The OBILE IP client has the IP decapsulation function removed, and only the address registration function functions. Reference numerals 121 and 122 denote NHSs prepared for IP subnets.

When the NHS receives the address resolution request for the designated IP address, the home agent 13
And a function of broadcasting a cache clear message to all ATM hosts and adjacent NHSs when data contents are updated as in the second embodiment. doing. The home agent 13 has a function of requesting the NHS 121 to transmit an address conversion request for a specified fixed IP address when receiving an IP address registration request.

FIG. 14 shows a registration procedure when the mobile ATM host 11 moves to an IP subnet other than its own home and a sequence when communicating with the fixed ATM host 6 in the mobile packet routing system shown in FIG. It is a sequence diagram shown. Next, the operation of this embodiment will be described with reference to FIGS. ATM
When the host 11 moves to an IP subnet other than the home, first, the ATM host 11
A TM address and a variable IP address are assigned.

Next, the NH installed in the ATM host 11 is
C registers the correspondence between the variable IP address and the ATM address in the NHS 122 in the NHRP procedure. Also, the MOBILE IP client of the ATM host 11 is
The correspondence between the P address and the fixed IP address of the ATM host is registered in the home agent 13. Up to this point NH
It is the protocol of RP and MOBILE IP itself.

Home agent 1 receiving the registration request
3 receives the address solution of the specified fixed IP address, and notifies the NHS 121 that it wants to make an inquiry. This trigger setting request is completely unique in the present invention, and FIG. 15 shows an example of a trigger setting request message (Destination Proto).
col Address and Client Prot
ocol Address is set to the target IP address).

At this point, the data shown in FIG. 16 is stored in the NHS 121. The data of the home agent 13 is the same as in FIG. NHS121 is IP address and AT
The correspondence between the M address and the fact that this is the IP address specified by the home agent 13 is stored.

At this time, the NHS 121 broadcasts a cache clear message to all managed ATM hosts and adjacent NHSs. The ATM host and the NHS receiving this message send the I
Clear the data at the P address. This mechanism is NHRP
NHRP Purge Re
Use the quest message.

The ATM host 11 sends an IP address to the ATM host 6.
When transmitting a packet, the ATM host 11
The IP address of the M host 6 is inquired to the NHS 122, and an ATM connection is set up using this ATM address. Then, an IP packet to the ATM host 6 is transmitted using this connection.

The ATM host 6 sends an IP address to the ATM host 11
When transmitting a packet, an inquiry is made to the NHS 122, but the fixed IP address of the ATM host 11 is not registered here, and the NHS 122 is registered in the normal NHRP procedure.
The inquiry message is transferred until S121.

Here, NHS 121 knows from the data of FIG. 16 that this fixed IP address is specified by home agent 13 and requests home agent 13 to convert the fixed IP address. The home agent 13 returns the variable IP address of the ATM host 11 from FIG. 4, and the NHS 121 continues address resolution using this IP address as a target. As a result, the inquiry message is transferred to the NHS 122, and the NHS 122
Thus, the ATM address of the ATM host 11 is resolved.

As a result, the shortest shortcut path is established between the ATM host 6 and the ATM host 11 without passing through the router and the home agent, and the IP packet is transferred. FIG. 17 is a flowchart showing the behavior of the NHS described above.

According to this embodiment, MOBILE
By considering the IP home agent as an IP address resolution server and operating NHRP and MOBILE IP in coordination, the movement of the ATM host across subnets can be realized, and the ATM-specific QoS control becomes possible from the application. This eliminates the processing delay caused by the intermediary and the processing delay caused by the return by the home agent.

Embodiment 8 FIG. In the eighth embodiment, instead of broadcasting the cache clear message,
Broadcast a cache update message. In particular, when the NHS receives the trigger setting request for the IP address, it broadcasts a cache update message. The ATM address set in the cache update message needs to be that of the ATM host 11, and this is notified together with the IP address in the trigger setting request transmitted by the home agent 13 (Cl
event NBMA Address & Subad
address).

MOBIL is sent to home agent 13.
It is assumed that the E IP client notifies the ATM address of the ATM host 11 at the time of registration of two IP addresses. The ATM host receiving this message updates the ATM address corresponding to the IP address. The format of the cache update message and its usage are completely the same as in FIG.

According to this embodiment, the local cache of the other ATM host is updated with the new information when the trigger is changed due to the movement of the ATM host. Therefore, the IP address resolution performed at the time of new communication with the mobile terminal is omitted, and the communication is performed. This has the effect of shortening the time required to establish

Embodiment 9 FIG. Embodiment 9 is based on NHS12.
By using the same device as the home agent 13 and the home agent 13, a part of the flow for address resolution is omitted.
At this time, the sequence between the NHS 121 and the home agent 13 in FIG. 14 becomes an optimized flow inside the same device and does not appear as an external message.

In the first to ninth embodiments, the moving ATM host is illustrated as a fixed terminal. However, the ATM host may be a device using wireless communication. In addition, it is assumed that the ATM host obtains its own IP address using DHCP when moving,
An IP address may be assigned using FOREIGN AGENT in accordance with IP regulations. In the fourth to ninth embodiments, the ATM is used to perform the broadcast.
Although it is assumed that the function of the ARP server or the NHS is extended, the MCS may be used as in the third embodiment.

According to this embodiment, the NHS and the home agent are integrated, and a part of the flow for address resolution is omitted, so that the processing capacity of the system can be improved.

[0084]

According to the first aspect of the present invention, the mobile packet routing system comprises IP over ATM and MOBI.
By operating the LE IP in cooperation, the movement of the ATM host across subnets can be realized, and the ATM
There is an effect that unique QoS control can be performed from the application.

According to the second invention, in this mobile packet routing system, the local cache of another host is cleared when the ATM host is moved, so that the local cache is aged until it is aged.
This has the effect of solving the problem that communication with the terminal that has moved to a new position becomes impossible.

According to the third aspect of the present invention, when the ATM host moves, the local cache of the other host is updated with new information, so that IP address resolution performed at the time of new communication with the mobile terminal is omitted, and communication is established. This has the effect of reducing the time it takes to complete.

According to the fourth invention, the ATM AR
Since the P server has a broadcast server function, it is possible to notify all terminals of the clearing or updating of the local cache to all terminals collectively, and the ATM ARP
The effect is that the performance is improved as compared with the case where the server sends a message to each terminal one by one.

Further, according to the fifth aspect of the present invention, the use of the broadcast function of the MCS by the ATM ARP server makes it possible to distribute the load and improve the performance of the system.

According to the sixth invention, NHRP and M
By operating the OBILE IP in cooperation, the movement of the ATM host across subnets can be realized, and the AT
The application also enables the QoS control specific to M to be performed from the application, and eliminates the processing delay caused by passing through the router.

According to the seventh aspect of the present invention, by clearing the local cache of another ATM host when the ATM host moves, communication with the mobile terminal moved to a new position until the local cache is aged. This has the effect of solving the problem that is impossible.

According to the eighth aspect of the present invention, when the ATM host moves, the local cache of another host is updated with the new information, so that the IP performed at the time of new communication with the mobile terminal is updated.
This has the effect of omitting address resolution and shortening the time until communication is established.

Further, according to the ninth aspect, MOBILE
By regarding the IP home agent as an IP address resolution server and operating NHRP and MOBILE IP in cooperation, the movement of the ATM host across subnets can be realized, and the QoS control specific to the ATM can be performed by the application. This eliminates the processing delay caused by the intermediary and the processing delay caused by the return by the home agent.

According to the tenth aspect of the present invention, the NHS and the home agent are integrated, and a part of the flow for address resolution is omitted, so that the processing capacity of the system can be improved.

According to the eleventh aspect of the present invention, the local cache of another ATM host is cleared when the trigger is changed upon the movement of the ATM host, so that the mobile terminal that has moved to a new position until the local cache is aged. This makes it possible to solve the problem that the communication becomes impossible.

Further, according to the twelfth aspect, when the trigger is changed due to the movement of the ATM host, the local cache of another ATM host is updated with the new information, so that the IP address resolution performed at the time of new communication with the mobile terminal is omitted. This has the effect of shortening the time until communication is established.

[Brief description of the drawings]

FIG. 1 is a network configuration diagram showing an embodiment of a mobile packet routing system according to the present invention.

FIG. 2 is a sequence diagram showing a registration procedure when the mobile ATM host 3 moves to an IP subnet other than home in the network configuration shown in FIG. 1, and an operation sequence when communicating with the fixed ATM host 6.

FIG. 3 is a diagram showing ATM A according to Embodiment 1 of the present invention;
This shows data in the RP server.

FIG. 4 shows data in a home agent according to the first embodiment of the present invention.

FIG. 5 is a sequence diagram showing a cache clear operation when an ATM host is moved according to another embodiment of the present invention.

FIG. 6 is a format example of a cache clear message according to the second embodiment of the present invention.

FIG. 7 is a network configuration diagram showing another embodiment of the mobile packet routing system according to the present invention.

FIG. 8 is an ATM network configuration diagram showing an ATM network configuration in another embodiment of the mobile packet routing system according to the present invention.

FIG. 9 shows a mobile packet routing system shown in FIG.
Registration procedure when moving to P subnet, and fixed A
FIG. 4 is a sequence diagram showing a sequence when communicating with a TM host 6.

FIG. 10 shows NHS9 in Embodiment 5 of the present invention.
The data in 1 is shown.

FIG. 11 shows NHS9 according to Embodiment 5 of the present invention.
2 shows the data in FIG.

FIG. 12 is a format example of a cache update message according to the sixth embodiment of the present invention.

FIG. 13 is a network configuration diagram showing an ATM network configuration in another embodiment of the mobile packet routing system according to the present invention.

14 is a sequence diagram showing a registration procedure when the mobile ATM host 11 moves to an IP subnet other than its own home and a sequence when communicating with the fixed ATM host 6 in the mobile packet routing system shown in FIG. is there.

FIG. 15 is a format example of a trigger setting request message according to the seventh embodiment of the present invention.

FIG. 16 shows data in the NHS according to the seventh embodiment of the present invention.

FIG. 17 is a flowchart showing NHS behavior in Embodiment 7 of the present invention.

FIG. 18 shows a conventional Mobile NHRP Devi.
FIG. 2 is an ATM network configuration diagram showing a network example to which ce is applied.

[Explanation of symbols]

Reference Signs List 1 ATM network 2 ATM router 3 Mobile ATM host equipped with ATM ARP and MOBILE IP client 5 Home agent operated in cooperation with home agent 91 cooperating with 41 6 Fixed ATM host 11 Mobile equipped with NHC and MOBILE IP extended client Home agent 14 that cooperates with ATM host 13 121 14 Mobile ATM host with NHC 41-42 ATM ARP server 121-122 Extended NHS

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-9-233085 (JP, A) JP-A 9-149036 (JP, A) JP-A-6-104926 (JP, A) JP-A-6-104926 337824 (JP, A) JP-A-9-130405 (JP, A) JP-A-10-32610 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04L 12/28 H04L 12 / 46 H04L 12/66 H04Q 7/38

Claims (12)

(57) [Claims] An ATM network is an ATM (Asy)
An ATM Transfer Mode (NAT) switch, an ATM router provided between subnets, an ATM host that is a mobile terminal that moves across subnets, and an ATM ARP (Address Res.) that resolves and outputs a destination ATM address based on an IP address.
solution ATM) and a home agent existing in the home subnet of the ATM host, and an IP over ATM.
ATM prepared for each of the above subnets based on the specifications of
The ARP server manages the correspondence between the ATM address and the IP address of the ATM router or the ATM host existing in the subnet and manages the MOBILE IP (RFC2
002, RFC: Request For Comme
home agent prepared for each subnet based on the specification of
The system is provided in a system configuration for managing the correspondence between a fixed IP address of a host and a variable IP address assigned when moving between subnets. When an ATM host moves across subnets, a newly acquired IP address and its own When the home agent registers (/ cancels) the correspondence with the fixed IP address in the home agent, the home agent registers (/ cancels) the association between the fixed IP address and its own ATM address in the ATM ARP server. The ATM host has a fixed I / O function when the ATM host moves to a subnet other than the home.
A mobile packet routing system, wherein an IP packet indicating a P address is transferred to the ATM host via the home agent. 2. When a fixed IP address is registered in the ATM ARP server or when registration is canceled, the ATM ARP server exists in the cache for all ATM hosts existing on the same subnet. 2. A request for clearing a correspondence table between the fixed IP address and the ATM address.
A mobile packet routing system as described. 3. When the fixed IP address is registered in the ATM ARP server, the ATM ARP server instructs all ATM hosts existing on the same subnet to the ATM corresponding to the fixed IP address existing in the cache. The mobile packet routing system according to claim 1, wherein a request is made to update the address to that of the home agent. 4. The ATM ARP server has a broadcast server function, so that all ATM hosts managed by the ATM ARP server are notified of a request for clearing or updating the cache at the same time. Or the mobile packet routing system according to 3. 5. MARS (Multicast Add)
MCS (Multi Cast Server) in accordance with the specification of the Resolution Solution Server.
r) in an ATM network and the ATM ARP
Standard MCS for all ATM hosts managed by the server
4. The mobile packet routing system according to claim 2, wherein requests for clearing or updating the cache are notified at the same time via a router. 6. An ATM network comprising: an ATM switch; an ATM router provided between subnets; an ATM host which is a mobile terminal moving across subnets;
S, a home agent existing in the subnet of the home of the ATM host, and an NHRP (Next)
Hop Resolution Protocol)
ATM routers and ATM hosts that have NHSs prepared for each subnet based on the specifications
Manages the correspondence between M addresses and IP addresses, and
A mobile packet routing system in which a home agent prepared for each subnet manages a correspondence relationship between a fixed IP address of an ATM host homed on the subnet and a variable IP address assigned when moving between subnets, based on the specification of ILE IP. In, AT
When the M host moves across subnets and registers (or releases) the correspondence between the newly acquired IP address and its own fixed IP address in the home agent, the home agent and the fixed IP address and its own ATM address Has a function to register (/ cancel) the association with the NHS, and when the ATM host moves to a subnet other than the home, an IP packet indicating the fixed IP address of the ATM host is transmitted via the home agent and the ATM router. Mobile packet routing system, wherein data is transferred to an ATM host without going through an ATM 7. When the fixed IP address is registered in the NHS or when the registration is released, the NHS is set to the ATM.
7. The mobile packet according to claim 6, wherein all ATM hosts and other NHSs existing on the network are requested to clear a correspondence table between the fixed IP address existing in the cache and the ATM address. Routing system. 8. When the fixed IP address is registered in the NHS, the NHS sends an ATM address corresponding to the fixed IP address existing in the cache to all ATM hosts existing on the ATM network and other NHSs. 7. The mobile packet routing system according to claim 6, wherein a request is made to update to a home agent. 9. An ATM network comprising: an ATM switch; an ATM router provided between subnets; an ATM host which is a mobile terminal moving across subnets;
S, which is composed of a home agent existing in the subnet of the home of the ATM host described above, and based on the NHRP specification, the correspondence between the ATM address and the IP address of the ATM router or ATM host in which the NHS exists in the subnet prepared for each subnet. MOBILE I
Based on the specifications of P, the home agent prepared for each subnet is an ATM whose home is this subnet.
In a mobile packet routing system for managing the correspondence between a fixed IP address of a host and a variable IP address assigned when moving between subnets, a fixed IP address in which the home agent is registered is changed to a variable IP address.
An address resolution function for converting to an address, and an address conversion request is made (or not made) at the time of reception (registration / release) of a fixed / variable IP address from an ATM host.
It has a trigger setting function to instruct the HS,
When the NHS receives the address resolution request and the target is a fixed IP address triggered by the home agent, the NHS requests the home agent to convert the fixed IP address and obtains the converted variable IP address. Later, using this as a target
A function to continue the address resolution procedure of P
When the TM host moves to a subnet other than the home, an IP packet indicating the fixed IP address of the ATM host is directly transferred to the ATM host without passing through the home agent and the ATM router. Mobile packet routing system. 10. The mobile packet routing system according to claim 9, wherein a flow for address resolution is partially omitted by integrating the NHS and the home agent. 11. When a home agent sets a trigger for a fixed IP address to the NHS,
Alternatively, when the trigger setting is released, NHS
For all ATM hosts and other NHSs on the TM network, the fixed I
10. The mobile packet routing system according to claim 9, wherein a request is made to clear a correspondence table between the P address and its ATM address. 12. When a trigger setting for a fixed IP address is requested from the home agent to the NHS,
Or, when the trigger setting is released, NHS
For all ATM hosts and other NHSs present on the M network, the fixed IP present in the cache
The mobile packet routing system according to claim 9, wherein the ATM address corresponding to the address is updated to that of the ATM host.