JP2012244497A - Mapping server and method of controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of controlling a mapping server capable of adjusting the priority in mapping information depending on a transmission source and a destination to make a notification, in a LISP network.SOLUTION: At a procedure (1), a mapping server 1 receives from an ETR registration associating a host identifier EID for a host in its LISP site with a position identifier RLOC of an ITR itself. At a procedure (2), mapping information is produced based on the registration. At a procedure (3), the ITR requests notification of the RLOC corresponding to the destination EID for LISP communication. At a procedure (4), the RLOC corresponding to the destination EID is found from the mapping information. In the case that a plurality of RLOCs are found, at a procedure (5), priorities of a plurality of destination RLOCs to the transmission source RLOCs are decided based on network information and the like. At a procedure (6), the ITR is notified of the plurality of destination RLOCs together with the respective priorities.

Description

  The present invention relates to a mapping server in a LISP network and a control method thereof, and in particular, a mapping server that can optimize traffic in a core network by adjusting and notifying priority in mapping information according to a transmission source and a destination, and It relates to the control method.

  Currently, LISP (Locator / ID Separation Protocol), which is being standardized by the Internet Engineering Task Force (IETF) for the purpose of reducing the number of Internet routes, etc., uses an ID for host identification and a Locator for routing. By using a host identifier (also called EID; Endpoint ID) for communication between hosts and using a location identifier (also called RLOC; Routing Locator) in the core network, the number of routes in the core network can be reduced. it can. LISP is disclosed in Non-Patent Document 1, but the outline is as follows.

  Fig. 4 shows a configuration example of a LISP network. LISP is a tunnel-based protocol that connects LISP sites with a LISP tunnel built on the core network. The mapping between EID and RLOC can be exchanged using a mapping server (LISP-MS (Map Server)). For this reason, the tunneling router xTR (Ingress or Egress Tunnel Router), which is placed in advance at the entrance / exit of the LISP site, pairs the ELOC (set, prefix) in its own site with the RLOC that the xTR itself has in the LISP-MS. sign up. The mapping server (LISP-MS) is disclosed in Non-Patent Document 2.

  The xTR of another LISP site that wants to communicate with a LISP site makes a mapping information notification request to LISP-MS using EID as a key. Simple authentication using Nonce (something like a hash key) is also performed when requesting registration or notification.

  For example, in FIG. 4, hosts with EIDs 10, 20 and 30 exist in the LISP sites 10, 20 and 30, respectively, and each LISP site is connected to the core network via xTR as a gateway router (tunnel router). Although the number of xTRs arranged at each LISP site can be set arbitrarily, in FIG. 4, two LTR sites 10 are designated xTR11 and xTR12 specified by the location identifiers RLOC11 and RLOC12, respectively. One xTR20 specified by RLOC20 and one xTR30 specified by RLOC30 are arranged at the LISP site 30, respectively.

  Each xTR registers its location identifier in advance in the mapping server LISP-MS in association with the host identifier in the LISP site where it is located. The mapping server holds the registration as mapping information. FIG. 4 shows an example of a portion related to the LISP site 10 in the mapping information. The location identifier EID10 is registered as prefix 2.0.0.0/8, the location identifier RLOC11 of one xTR11 corresponding to the EID10 is registered as the IP address 12.0.0.2, and the location identifier RLOC12 of the other xTR12 corresponding to the EID10 is also registered. Is registered as IP address 13.0.0.2.

  LISP site 10 has two xTRs. When a plurality of xTRs are arranged in this way, additional information other than the association between EID and RLOC may be registered in the mapping information. That is, as shown in the figure, the priority for use of each xTR may also be registered as mapping information according to a value preset by the operator of the LISP site 10. The priority can be set by two parameters, for example, priority and weight as shown in the figure. RLOC11 and RLOC12 are registered so that the priorities according to the parameters are uniform.

  Although not shown, mapping information is also registered from each xTR from other LISP sites. For example, xTR20 registers the associated EID20-RLOC20 and xTR30 registers the associated EID30-RLOC30 in the mapping information as an IP address in the same manner as described above.

  In FIG. 4, communication by LISP will be described using an example in which a packet is transmitted from an EID20 host to an EID10 host. As shown in (a), the host EID 20 transmits a packet whose inner header is “source (src) EID20, destination (dst) EID10”. The packet is encapsulated when it reaches xTR20 of RLOC20 and is given an outer header.

  Here, there are two types of outer headers to which the packet is attached. In the first case, as shown in (b1), the packet is given “source (src) RLOC20, destination (dst) RLOC11” as an outer header, transferred through the core network, and reaches xTR11 of RLOC11. In the second case, as shown in (b2), the packet is given “source (src) RLOC20, destination (dst) RLOC12” as the outer header, transferred through the core network, and reaches xTR12 of RLOC12.

  In order to assign the outer header, xTR20 requests to refer to and notify the necessary part of the mapping information managed to LISP-MS. At the destination LISP site 10 where EID10 exists, the priority specified by the priority and weight is registered in the mapping information so that it is uniform between RLOC11 and RLOC12. Street outer headers are given in equal proportion to each other. If only RLOC11 is registered, or RLOC12 is registered, but only RLOC11 is registered for priority specification, all packets follow the first case shown in (b1). It becomes.

  The packet (b1) is decapsulated when it reaches xTR11 of RLOC11, is transferred within the LISP site 10 as shown in (c1), and reaches the host of EID10. The packet (b2) is also decapsulated when it reaches xTR12 of RLOC12, and is transferred within the LISP site 10 as shown in (c2) to reach the host of EID10.

  In the LISP network, the hosts in each LISP site can communicate using only EID. A conventional ordinary IP address independent of LISP can also be used for EID, so hosts in each LISP site can communicate without any changes. RLOC is also an IP address, but since it can be set separately from EID, it has the advantage of reducing the number of core network paths.

Locator / ID Separation Protocol (LISP), http://tools.ietf.org/html/draft-ietf-lisp-12 LISP Map Server, http://tools.ietf.org/html/draft-ietf-lisp-ms-08

  In FIG. 4, in the LISP site 10 where a plurality of xTRs are arranged, in addition to the association EID1-RLOC11 and EID1-RLOC12, the operator of the LISP site 10 can set the priority for using each xTR. Mapping information that is referenced when the host in the LISP site 10 is the destination is registered in the mapping server LISP-MS. However, the priority is uniformly registered regardless of the transmission source that makes the mapping reference request.

  That is, in the example of matching information of the LISP site 10 in FIG. 4, when the priority order and priority by weighting are registered to be uniform between RLOC11 and RLOC12, the EID10 host of the above-mentioned LISP site 20 is used as the transmission source. RLOC11 (specified by xTR11) and RLOC12 (specified by xTR12) not only when the destination is used, but also when EID10 is the destination by using the EID30 host at the LISP site 30 as another source. Are uniformly used for each series of packet communications. That is, the paths (d)-(e1)-(c1) and (d)-(e2)-(c2) are used uniformly.

  Such uniform setting of priority for each destination LISP site is not preferable from the viewpoint of efficient operation of the core network. In other words, if (b1) and (b2) are routes with almost the same load, the communication of the source EID20 and the destination EID10 is evenly distributed to xTR11 and xTR12 according to the setting example in FIG. It will be. However, if (e1) is a route with a lower load than (e2), according to the setting, communication of the transmission source EID30 and the destination EID10 places an excessive load on xTR12.

  Also, if the mapping information is registered by increasing the priority of xTR11 so that the communication of the transmission source EID30 / destination EID10 is optimal under the above path load assumption, conversely the transmission source EID20 / destination EID10 Communication will overload xTR11.

  In other words, in the conventional technology, the operator of the LISP site 10 sets the same priority for the multiple RLOCs corresponding to the destination EID10. Cannot be operated. Further, such uniform priority setting is not preferable from the viewpoint of general efficient operation of the core network, not limited to traffic optimization.

  An object of the present invention is to solve the above-described problems of the prior art, and to a mapping information notification request, a mapping server capable of adjusting and notifying a priority in mapping information according to a transmission source and a destination And providing a control method thereof.

  In order to achieve the above object, according to the present invention, routing is performed by a location identifier in a core network, and routing is performed by a host identifier in each LISP site connected to the core network as a lower layer network through a tunneling router. In the control method of the mapping server that holds the correspondence between the location identifier and the host identifier as mapping information in the LISP network to be performed, from the tunneling router of each LISP site, the location identifier of the tunneling router and the host identifier in the LISP site The mapping information is received in response to a notification request from the transmission source tunneling router in which a step of generating mapping information is received and a location identifier of the transmission source tunneling router and a host identifier of the destination host are described. Refer to the destination When there are a plurality of destination tunneling router position identifiers corresponding to the host identifier of the host, determining the priority of the plurality of destination tunneling router location identifiers with respect to the source tunneling router location identifier; and And notifying a source tunneling router of the location identifiers of the plurality of destination tunneling routers together with the determined priority.

  Further, the present invention provides a location in a LISP network in which routing is performed by a location identifier in the core network, and routing is performed by a host identifier in each LISP site connected to the core network as a lower layer network via a tunneling router. In the mapping server that holds the correspondence between the identifier and the host identifier as mapping information, the tunneling router at each LISP site accepts a registration that associates the location identifier of the tunneling router and the host identifier in the LISP site, and mapping information Receiving a notification request from the transmission source tunneling router in which the location identifier of the transmission source tunneling router and the host identifier of the destination host are described, and referring to the mapping information, Host identifier of the host A priority determination unit that determines the priority of the location identifiers of the plurality of destination tunneling routers with respect to the location identifier of the source tunneling router when there are a plurality of location identifiers of the destination tunneling router corresponding to And a notification unit that notifies the source tunneling router of the location identifiers of the plurality of destination tunneling routers together with the determined priority.

  According to the present invention, the priority of the location identifiers of a plurality of destination tunneling routers corresponding to the location identifiers of the source tunneling routers can be determined and notified as mapping information. Therefore, by performing LISP communication according to the notification, traffic in the core network can be optimized.

It is a figure which shows the example of the LISP network for demonstrating this invention. It is a functional block diagram of a mapping server. It is a figure which shows the procedure of the control method of a mapping server. It is a figure which shows the example of a LISP network for demonstrating the subject in a prior art.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is an example of a LISP network used to explain the present invention. As in the case of FIG. 4, mapping server 1 (LISP-MS) is arranged in the core network that is the upper layer network, and the LISP sites 1, 2, and 3 that are the lower layer networks are assigned host identifiers EID1, 2, and 3, respectively. The specified host exists. In LISP site 1, two xTRs, xTR1-1 and xTR1-2, are arranged, and each xTR is designated by position identifiers RLOC1-1 and RLOC1-2. In LISP site 2, xTR2 designated by location identifier RLOC2 is arranged, and in LISP site 3, xTR3 designated by location identifier RLOC3 is arranged. The arrangement in FIG. 1 is an example for explaining the present invention, and the number of xTRs and the like can generally be arbitrarily set.

  FIG. 2 is a functional block diagram of the mapping server 1 of the present invention. The mapping server 1 includes a mapping information creation unit 2, a priority determination unit 3, and a notification unit 4. The mapping information creation unit 2 includes a mapping database (mapping DB) 21. The priority determination unit 3 includes a network information database (network information DB) 31.

  The mapping information creation unit 2 creates mapping information including correspondence information between the host identifier EID and the location identifier RLOC, and stores the mapping information in the mapping DB 21. The priority determination unit 3 determines the priority between the position identifiers (that is, between xTRs specified by the position identifier) based on the network information held in the network information DB 31 and the like. The notification unit 4 encapsulates the packet and forwards it within the core network, and notifies the RTR of the destination LISP site with the priority information to the xTR of the source LISP site that requests the notification of the RLOC of the destination LISP site. .

  FIG. 3 is a diagram showing the procedure of the control method of the mapping server 1 of the present invention. In FIG. 3, after passing through the control method, xTR is determined according to the direction in which the data packet of LISP communication is transmitted and received, the source ITR (Ingress Tunnel Router; responsible for encapsulation), and the destination ETR (Egress Tunnel Router ; In charge of decapsulation). That is, xTR that requests notification of the location identifier of the destination LISP site corresponding to the host identifier EID of the destination is described as ITR, and xTR that belongs to the destination LISP site and registers the host identifier in its own site is described as ETR. ing.

  In FIG. 3, the procedure will be described assuming that ITR is xTR2 or xTR3 (of FIG. 1) and ETR is xTR1-1 and xTR1-2. In procedure (1), each xTR in the LISP network registers the host identifier EID of the host existing in its own LISP site and its location identifier RLOC in association with the mapping server 1.

  Note that in step (1), when there are multiple xTRs in one LISP site, as with the prior art, the LISP site operators set their own priority information regarding the use of each xTR along with the RLOC. You may register. However, in the present invention, registration of priority information from the LISP site side may be omitted. The priority is set by the core network operator in step (5), which will be described later, so that the operation of the core network can be optimized while reducing the burden on each LISP site operator.

  In the configuration example of FIG. 1, the ETRs xTR1-1 and xTR1-2 each register with the mapping server 1 as an example of the procedure (1). xTR1-1 associates the host identifier EID1 of the host in its own site with its own location identifier RLOC1-1, and information on the priority of the location identifier (priority p = 1, [priority = 1], weight w = 50 [weight = 50]). xTR1-2 also associates host identifier EID1 with its location identifier RLOC1-2, and registers it with location identifier priority information (p = 1, [priority = 1], w = 50 [weight = 50]) To do. The priority and weight will be described later.

  The registration of xTR1-1 and xTR1-2 is an example in which the priorities of both are equal. Further, at the time of registration, authentication data AD1 (AD; Authentication Data) shared in advance by xTR1-1 and xTR1-2 and the mapping server 1 is used so that EID1 is properly registered.

In step (2), the mapping creation unit 2 creates mapping information based on the information that has been successfully authenticated and registered in step (1), and stores it in the mapping DB 21. In the registration example described above, the following mapping information is created by associating the host identifier EID1 with the two location identifiers RLOC together with information indicating the respective priorities.
EID1 {RLOC1-1, p = 1, w = 50}
EID1 {RLOC1-2, p = 1, w = 50}

  In step (3), the ITR requests the mapping server 1 to notify the destination location identifier. In the example shown in the figure, the xTR2 encapsulates a packet having the host identifier EID2 in its own LISP site 2 as the source and the destination as the host with the host identifier EID1, and therefore requests a notification of the location identifier corresponding to the destination EID1. Do. At the time of the request, the location identifier RLOC2 of xTR2 itself is also transmitted to the mapping server 1.

  That is, in step (3), xTR2 is the main information in the notification request, as shown in the figure, the host identifier (EID1) of the destination host and the location identifier (RLOC2) of xTR2 (IRT) itself belonging to the source LISP site. Is described in a predetermined control packet and transmitted to the mapping server 1.

  In the procedure (4), the priority determination unit 3 refers to the mapping DB 21 using the destination EID and the transmission source RLOC transmitted in the procedure (3). With this reference, the location identifier RLOC corresponding to the destination EID in the mapping information is found as the first information to be sent back to the ITR. In the illustrated example, RLOC1-1 and RLOC1-2 are found as location identifiers corresponding to the host identifier EID1.

  In step (5), for the location identifiers RLOC of a plurality of destinations that are found as in the above example, the priority determination unit 3 sends a reply to the ITR according to the relationship with the source location identifier RLOC. The priority of each destination RLOC is determined as information. There are various types of embodiments for determining the priority. Basically, the priority is determined by referring to the network information DB 31 and using the network information determined by the source location identifier and the destination location identifier. The The network information may be prepared in advance in the network information DB 31, or after the steps (3) and (4), the priority determining unit 3 acquires necessary information and stores it in the network information DB 31. Good.

  In one embodiment, as illustrated, a delay value (delay) between xTRs corresponding to a destination and a source location identifier is used. For example, the delay value is 30 (delay = 30) between the first destination RLOC1-1 and the source RLOC2, and the delay value is 70 (delay = 30) between the second destination RLOC1-2 and the source RLOC2. 70). That is, RLOC1-1 has a shorter network distance. Therefore, from the viewpoint of improving the core network operation efficiency, the priority is determined to be higher for RLOC1-1 and lower for RLOC1-2. In step (6), the notification unit 4 returns the location identifier RLOC corresponding to the destination host identifier EID included in the notification request to the ITR together with its priority.

The priority determined in step (5) and notified in step (6) is defined by priority and weight. At this time, as described above, in order to define a priority level in which RLOC1-1 is high and RLOC1-2 is low as described above, the high and low ranks may be directly associated with the priority rank priority. In the example shown in the figure, according to the method, the position identifier corresponding to the destination EID1 is
RLOC1-1, p = 1, w = 100
RLOC1-2, p = 2, w = 100
And reply with priority. In this case, the LISP communication of the transmission source EID2-destination EID1 is performed only through the RLOC1-1 as long as the first-place RLOC1-1 is available.

Further, as the second method, the priority may be defined in the form of weighting of xTR use distribution based on the parameter that is the priority determination criterion. For example, in the delay value examples RLOC1-1 (delay = 30) and RLOC1-2 (delay = 70), the priorities are equal and the weights are appropriately distributed as follows. Thus, the priority may be returned.
RLOC1-1, p = 1, w = 70
RLOC1-2, p = 1, w = 30

  Normally, RLOC having a high priority (ie, a smaller number) is given priority, and when the priority is the same, the load is distributed according to the weighting weight. The weight must be 100 in total within the same priority. In other words, the priority is determined by a pair of two parameters of priority and weighting. At this time, priority is the main parameter. Weighting is a subordinate parameter that is assigned to RLOCs having a common priority and is used for further prioritization.

  The ITR (xTR2) that has received the reply performs encapsulation as described with reference to FIG. 4 at a step (not shown), and LISP communication between the transmission source EID2 and the destination EID1 is performed. As described above, in the present invention, the priority is determined for the combination of the source RLOC and the destination RLOC in consideration of the network information between the two, so each LISP site determines the priority at a fixed level. Compared with the prior art, the core network can be operated more efficiently and traffic optimization can be realized.

  For example, in the example of Fig.3, when in step (3), xTR3 (ITR) requests RLOC notification corresponding to destination EID1 together with its own RLOC3 for encapsulation of communication of source EID3-destination EID1 A priority independent of the above-described case of xTR2 is determined. First, procedure (4) is similar to the above example, and RLOC1-1 and RLOC1-2 corresponding to EID1 are found.

In step (5), assuming that the delay value is 60 (delay = 60) between RLOC1-1 and RLOC3 and 40 (delay = 40) between RLOC1-2 and RLOC3, step (6) If you want to reflect the priority response example in the priority order,
RLOC1-1, p = 2, w = 100
RLOC1-2, p = 1, w = 100
If it is reflected in the weight,
RLOC1-1, p = 1, w = 40
RLOC1-2, p = 1, w = 60
When the transmission source is RLOC3, the priority determined independently from the case of RLOC2 is returned and notified. That is, even for the same destination EID, the reply changes according to the transmission source RLOC, and the traffic of the core network is optimized. Hereinafter, additional and modified embodiments and supplementary items will be described as [A] to [C].

  [A] In step (4), if there is only one RLOC corresponding to the destination EID, only that RLOC will be automatically returned, so in step (5), refer to the network information DB31 in particular. There is no need to do so. Then, the one RLOC may be returned in step (6). The present invention particularly relates to the case where there are a plurality of RLOCs corresponding to the destination EID.

  [B] The priority information registered from each LISP site in step (1) is not basically used from the ITR side making the notification request, or the priority is rewritten. Will be used. Therefore, as described above, registration of priority information may be omitted in step (1).

  However, on the contrary, if the LISP site side wants to specifically set the use of RLOC, the present invention may not be applied. That is, in the procedure (5), priority determination with reference to the network information DB is not performed, and the priority determination unit 3 may refer to the mapping DB 21 and use the priority in the original mapping information. The present invention may be applied when the RLOC usage setting on the LISP site side has the same priority and the usage allocation setting request is not particularly seen. The mapping server 1 may be operated while using both the RLOC to which the present invention is applied and the RLOC to which the present invention is not applied.

  [C] The priority of the procedures (5) and (6) may be determined based on the band information, not the delay value between the destination RLOC and the transmission source RLOC. The delay value and the band information are preferably acquired by the priority determination unit 3 after receiving the notification request in the procedure (3), but values acquired in advance may be used. Alternatively, it may be determined based on the carrier of the destination RLOC and the source RLOC. For example, the priority may be increased when the carriers are the same.

  The priority may be determined based on the notification request reception time. In the example of Fig. 3, RLOC1-1 is given priority if it is 0:00 to 12:00 (in the morning), and RLOC1-2 is given priority if it is 12:00 to 24:00 (afternoon). You may do it.

  Alternatively, the priority may be determined based on the xTR operating rate (CPU usage rate, etc.) corresponding to each destination RLOC in the notification request time or a predetermined period before that time. Increase the priority of RLOCs with low availability and decrease the priority of RLOCs with high availability.

  As for the criteria for determining the priority, only one of the various types as described above may be used, or a plurality of criteria may be used in combination with predetermined weighting or condition classification. .

By adjusting the priority priority and the weighting weight values, in addition to replying with the priority given to all RLOCs, excluding the predetermined number of RLOCs on the lower priority side so that no reply is made. May be. For example, the following example in Figure 3
RLOC1-1, p = 1, w = 50
RLOC1-2, p = 2, w = 50
Instead of only the first line
RLOC1-1, p = 1, w = 100
You may reply as

As a method similar to the above reply, the RLOC to be used may be more explicitly defined by priority than weight. For example, for a certain source RLOC, if the destination RLOC and priority for a certain destination EID are RLOC4 and RLOC5 are 1st in the same rank and RLOC6 is 2nd, if the 1st is uniformly allocated by weight, Will reply as follows:
RLOC4, p = 1, w = 50
RLOC5, p = 1, w = 50
RLOC6, p = 2, w = 100

However, in the above method, depending on the implementation of xTR, even if w = 50 is defined, there is a possibility that RLOC4 and RLOC5 cannot be allocated uniformly. Therefore, for each of a plurality of notification requests that specify the RLOC to be used by priority and share the same source RLOC and destination EID, the following (Reply 1) and (Reply 2) are alternately or in a uniform ratio. Try to reply.
(Reply 1)
RLOC4, p = 1, w = 100
RLOC5, p = 2, w = 100
RLOC6, p = 3, w = 100
(Reply 2)
RLOC4, p = 2, w = 100
RLOC5, p = 1, w = 100
RLOC6, p = 3, w = 100

  Similarly, in addition to the reply with a uniform ratio, a reply with a desired ratio according to the priority may be used. For example, if you want to use 70% of the first-place RLOC (for example, delay = 30) and 30% of the second-place RLOC (for example, delay = 70), p = 1 for the first-place RLOC and p for the second-place RLOC It is also possible to use 70% of responses with = 2, 30% of responses with p = 2 for the 1st RLOC and p = 1 for the 2nd RLOC.

  1 ... Mapping server, 2 ... Mapping information creation unit, 21 ... Mapping DB, 3 ... Priority determination unit, 31 ... Network information DB, 4 ... Notification unit

Claims (6)

In the LISP network in which routing is performed by the location identifier in the core network, and routing is performed by the host identifier in each LISP site connected to the core network as a lower layer network via a tunneling router, the location identifier and the host identifier In the control method of the mapping server that holds the mapping of
From the tunneling router of each LISP site, accepting registration in which the location identifier of the tunneling router and the host identifier in the LISP site are associated, and creating mapping information;
In response to a notification request from the source tunneling router in which the location identifier of the source tunneling router and the host identifier of the destination host are described, the mapping information is referred to and destination tunneling corresponding to the host identifier of the destination host Determining a priority of the location identifiers of the plurality of destination tunneling routers in relation to the location identifier of the source tunneling router when there are a plurality of location identifiers of the router;
A step of notifying the source tunneling router of the location identifiers of the plurality of destination tunneling routers together with the determined priority.   In the step of determining the priority, the priority is determined based on at least one of a delay value and bandwidth information between the transmission source tunneling router and the plurality of destination tunneling routers. 2. The mapping server control method according to claim 1, wherein   3. The mapping server control method according to claim 1, wherein, in the step of determining the priority, the priority is determined based on a time when the notification request is received.   4. The mapping server control method according to claim 1, wherein in the step of determining the priority, the priority is determined based on an operating rate of the plurality of destination tunneling routers. . In the step of determining the priority, the priority is determined by a priority and a weight given to position identifiers having the same priority.
In response to a plurality of notification requests in which the location identifier of the source tunneling router and the host identifier of the destination host are common, in the notification step, the location identifier of the plurality of destinations at a ratio based on the determined priority. 5. The mapping server control method according to claim 1, wherein each is notified as the highest priority. In the LISP network in which routing is performed by the location identifier in the core network, and routing is performed by the host identifier in each LISP site connected to the core network as a lower layer network via a tunneling router, the location identifier and the host identifier In the mapping server that holds the mapping of as mapping information,
From the tunneling router of each LISP site, accepting registration that associates the location identifier of the tunneling router and the host identifier in the LISP site, and a mapping information creation unit that creates mapping information,
In response to a notification request from the source tunneling router in which the location identifier of the source tunneling router and the host identifier of the destination host are described, the mapping information is referred to and destination tunneling corresponding to the host identifier of the destination host A priority determination unit that determines the priority of the location identifiers of the destination tunneling routers that exist in a plurality with respect to the location identifier of the source tunneling router when there are a plurality of location identifiers of the router;
A mapping server, comprising: a notification unit that notifies the transmission source tunneling router of the location identifiers of the plurality of destination tunneling routers together with the determined priority.