CN110099005B

CN110099005B - Information center network route optimization method based on redirection

Info

Publication number: CN110099005B
Application number: CN201910420844.4A
Authority: CN
Inventors: 杨武
Original assignee: Harbin Insec Information Technology Co ltd
Current assignee: Harbin Insec Information Technology Co ltd
Priority date: 2019-05-20
Filing date: 2019-05-20
Publication date: 2021-05-28
Anticipated expiration: 2039-05-20
Also published as: CN110099005A

Abstract

The invention discloses a redirection-based information center network route optimization method, which comprises the following steps: step one, defining a packet and table structure in the network route of the information center based on redirection: modifying a packet and table structure in the NDN based on the NDN, wherein: the structures that need to be modified or added are: (1) modifying the format of the interest packet message; (2) adding a notification packet; (3) adding a position change packet; (4) adding an RT table; step two, defining a forwarding strategy: and forwarding four packets, namely a data packet, an interest packet, a notification packet and a position change packet. The invention provides an ICN route optimization strategy based on redirection, which can ensure that data transmission can be normally carried out when a content producer moves, and has less cache redundancy compared with other current routing strategies.

Description

Information center network route optimization method based on redirection

Technical Field

The invention relates to a route optimization method, in particular to a route optimization method based on redirection.

Background

With the popularization of the internet and internet of things technology, the Network traffic begins to increase rapidly, and the application range and the scale of the current internet are far beyond the original design purpose, so that an Information-Centric Network (ICN) is proposed. The current information center network has protocols such as NDN, PSIRP, DONA, NetInf and the like, although the protocols have different expression forms, the core idea is that the information name or ID is adopted to obtain the content, the information is not concerned about where the information comes, all the routers flowing through are supported to cache the information, and when the user requests the same information, the routers can directly return the information without forwarding the request to the server. Among the many information center Network implementations, the most popular feasible scheme is Named Data Network (NDN), hereinafter referred to as NDN, and all schemes discussed in the present invention are based on NDN.

Although ICN reconsidered some optimization and innovative design concepts, in many respects some core problems have not been thoroughly solved in the early ICN network framework.

Disclosure of Invention

In order to solve the problems of data transmission interruption and cache redundancy caused by the movement of a content producer in an information center network, the invention provides an information center network route optimization method based on redirection, which mainly discusses the problem of mobility. The information center network has good natural support for the movement of content consumers, but lacks good support for the movement of content producers, so the invention provides a new route optimization strategy, named NDN-PR, which reduces the cache redundancy while keeping the data transmission uninterrupted.

The purpose of the invention is realized by the following technical scheme:

a redirection-based information center network route optimization method comprises the following steps:

step one, defining packet and table structure in redirection-based information center network routing

Modifying a packet and table structure in the NDN based on the NDN, wherein: the structures that need to be modified or added are:

(1) modifying the message format of the interest packet, and adding a field in the interest packet: a location name field;

(2) adding a notification packet, and sending out the notification packet when the content producer moves, wherein the notification destination address is the position before moving, and the new position is the position of the current new access point;

(3) adding a position change packet, informing a content consumer that the content consumer should resend and change the destination address of the interest packet by adopting an active push mode, and simultaneously recording the movement of the position through a table so that all the interest packets in the following are sent to a new position;

(4) adding an RT table, wherein the RT table comprises two fields of a content name and a position;

step two, defining a forwarding strategy

(1) When an interest packet arrives at the router, assuming that the arrival port is I, the router will sequentially check the CS table, the RT table, the PIT table and the FIB table, and then:

(a) comparing the content name field of the interest packet with the content name field of the CS cache table, if corresponding content is found in the CS cache of the route, directly discarding the interest packet, taking the content cached in the CS as a data packet, returning from a port I where the interest packet arrives, and ending;

(b) if the content name field of the interest packet is not found in the CS table, comparing the content name field of the interest packet with the content name of the RT table, if the matching of the content names is found in the RT table, comparing the position item where the interest packet is located with the position name item where the interest packet is located, if the two are not consistent, indicating that the current interest packet cannot obtain feedback at the position requested in the packet, the position of the data has moved, at this moment, constructing a position change packet to notify a content consumer, filling a new position name field in the position field of the table, filling the content name in the position change packet with the content name in the packet, then sending out from a port I, directly discarding the interest packet, and ending;

(c) if the matched content name is not found in the RT table, or the content name and the position in the interest packet are consistent with those in the RT table, which indicates that the current interest packet neither needs to be redirected nor finds a cache locally, the PIT table is searched at the moment, if an item corresponding to the content name is found in the PIT, the arrival port I of the interest packet is added into the matched PIT item, the interest packet is discarded, and the operation is finished;

(d) if no matching item is found in the PIT table, the data interest packet is shown to arrive for the first time, the position item of the interest packet is compared with the content name in the FIB table, if the matching item is found, the interest packet is forwarded according to the port of the matching item, meanwhile, the content name field in the current interest packet is added into the PIT table, and the operation is finished;

(e) if no match is found, data cannot be found, discarding the data packet, and ending;

(2) when the router receives the data packet, returning the data packet according to the PIT table, and deleting the corresponding content item of the PIT table;

(3) when the notification packet arrives at the router, there are:

(a) checking whether the survival time of the notification packet is 0 or not, and directly discarding the data packet if the survival time of the notification packet is 0;

(b) if the notification destination address in the notification packet is the router, the router updates the RT table of the router, if the content name in the packet exists in the RT table, the position in the RT table is changed into a new position name in the notification packet, if the content name does not exist, the position is added into the RT table, and the content name and the new position name are respectively filled; if the matching indicates that the node is a node before the content producer moves, a large number of interest packets for requesting content from the location may exist in the network, the route stores a copy of the redirection table, and the redirection information is stored at a node closer to the user; after updating the RT table of the router, the router sends a position change packet to a place closer to a content consumer;

(c) searching whether a matching item exists between the notification destination address and the content name field in the FIB table, if the matching item exists, subtracting 1 from the survival time by the router, and then forwarding the notification packet according to the FIB table;

(4) when the router receives the position change packet, the NF packet is forwarded to the content consumer by using the PIT table, and the specific steps are as follows:

(a) if the content name identical to the position change packet is found in the RT table, changing the position in the RT table into a new position name in the LC packet, and then jumping to (c);

(b) if the corresponding content name is found in the RT table, directly creating a corresponding entry, and then jumping to (c);

(c) if the corresponding content name is found in the PIT table, forwarding the packet from an interface corresponding to the PIT table, and deleting the item in the PIT table;

(d) if the corresponding content name is not found in the PIT table, the LC packet is directly discarded.

(5) When the position change package reaches the content consumer, the content consumer immediately reconstructs the interest package according to the position change package and sends the interest package, and the new position name is used for filling the position name of the interest package and sending the interest package from the interface.

Compared with the prior art, the invention has the following advantages:

the invention provides an ICN route optimization strategy based on redirection, which can ensure that data transmission can be normally carried out when a content producer moves, and has less cache redundancy compared with other current routing strategies.

Drawings

FIG. 1 is a diagram of a packet format;

FIG. 2 is a diagram of an interest package format;

FIG. 3 is a diagram of a notification packet format;

FIG. 4 is a diagram of a change of location packet format;

FIG. 5 is a schematic diagram of the structure of an RT table;

FIG. 6 is a flow chart of interest packet forwarding;

FIG. 7 is a notification packet processing flow diagram;

FIG. 8 is a flow chart of a location change packet process;

FIG. 9 is a tree network topology;

FIG. 10 is a ring network topology;

FIG. 11 is a comparison graph of an average receiving experiment under a tree topology;

FIG. 12 is a graph comparing average transmission delays of control packets;

FIG. 13 is a comparison graph of average data reception delay under a ring topology;

FIG. 14 is a diagram of a network topology structure;

FIG. 15 is an interest packet followed by a notification packet;

FIG. 16 is a notification package followed by an interest package.

Detailed Description

The technical solution of the present invention is further described below with reference to the accompanying drawings, but not limited thereto, and any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be covered by the protection scope of the present invention.

NDN-PR is an abbreviation for NDN-Path Redirect, which has four packages:

(1) data packet (Data packet): format as shown in fig. 1, NDN-PR uses exactly the same packet as NDN, which is a minimized packet format to ensure that the packet can be cached by the router.

(2) Interest package (Interest package): the format is shown in fig. 2, a field is added in the interest packet, the field is a location name field, the field indicates the actual location of the content, and the routing table is forwarded according to the field and is not forwarded according to the content name. This is because the content producer may move without the forwarding table changing accordingly, and thus the content name may not exactly match the location.

(3) Notification packet (Notify packet, NF packet for short): the format is shown in 3, when the content producer moves, it sends out the notice packet, the notice destination address is the position before moving, the new position is the position of the new access point, the content name identifies the concrete content of moving, the time-to-live field is a field existing to prevent the router notice packet from generating loop, and is similar to the TTL of IP network. This type of packet generation is due to the fact that when a content producer moves, the change in the NDN network topology is not immediately perceived by the network nodes, and therefore a notification packet needs to be actively sent to indicate the currently moving content and the location name of the new access point. The destination address of the notification packet is the original access location, because after the movement occurs, the content consumer cannot perceive the movement, and the current network requests for the content are sent to the access point before the movement, so that the original access point is notified of the movement of the content, and a redirected location reference is provided for a subsequent routing algorithm.

(4) The format of the Location-Change packet (LC packet for short) is shown in fig. 4, where the Location-Change packet is a packet sent by a router at an original access Location, and is intended to notify a content consumer sending a packet of interest that the Location of a requested content producer has changed, and the request packet should be sent again at a new Location to obtain data. The message informs the content consumer that the destination address of the interest packet should be retransmitted and changed by adopting an active push mode, and simultaneously records the movement of the position through a table, so that all the interest packets in the following process are sent to a new position. By adopting the push mode, the network delay can be reduced, so that the content consumer does not need to wait for the interest packet to be processed after overtime.

In the Table format, the NDN-PR does not modify the FIB Table, the PIT Table, and the CS Table in the original NDN, the PIT still records an interface waiting for receiving data, the FIB Table is also used to represent a forwarding Table as in the original NDN, but in order to implement a redirection function, a router needs to add a redirection Table (RT for short).

Two fields of the RT table are shown in fig. 5, a content name and a location, the RT table is used to record a network location of the current content, the RT table is very simple in design, only two fields are used to identify the location of the content, and the content name and the location field are both filled with the content name in the NDN. And only the location change packet and the notification packet can change the value of the table, which can be guaranteed by the routing algorithm described below, the RT table can be updated at a location very close to the content consumer, the content consumer can directly redirect the new location of the content producer to send out the interest packet, and the existence of the table is also one of the reasons for the high efficiency of NDN-PR.

The flow of NDN-PR forwarding four packets is as follows:

(1) when an interest packet arrives at the router (the interest packet includes three fields), assuming that the arriving port is I, the router will sequentially check the CS table, the RT table, the PIT table, and the FIB table, and the forwarding flow chart is shown in fig. 6.

(a) And comparing the content name field of the interest packet with the content name field of the CS cache table, if corresponding content is found in the CS cache of the route, directly discarding the interest packet, taking the content cached in the CS as a data packet, returning from a port I where the interest packet arrives, and ending. The CS may employ a different caching algorithm that does not affect the flow of the algorithm and therefore does not need to consider this issue.

(b) If the content name field of the interest packet is not found in the CS table, comparing the content name field of the interest packet with the content name of the RT table, if the content name is matched with the RT table, comparing the location item with the location name item of the interest packet, and if the content name field of the interest packet is not matched with the content name field of the RT table. And (3) explaining that the current interest packet can not be fed back at the requested position in the packet, the position of the data is moved, a position change packet should be constructed to notify a content consumer at the moment, a new position name field is filled in the position field in the table, the content name in the position change packet is filled in the content name in the packet, then the packet is sent out from a port I, the interest packet is directly discarded, and the process is finished.

(c) If the matched content name is not found in the RT table, or the content name and the position in the interest packet are consistent with those in the RT table, it is indicated that the current interest packet neither needs to be redirected nor finds a cache locally, at this time, the PIT table needs to be searched if the current interest packet is consistent with the original NDN process, if an entry corresponding to the content name is found in the PIT, the arrival port I of the interest packet is added into the matched PIT entry, the interest packet is discarded, and the process is ended.

(d) If no matching item is found in the PIT table, it is indicated that the data interest packet arrives for the first time, it should be noted that although the process is similar to the original NDN, what needs to be compared with the FIB table is the location item in the interest packet and the content name in the FIB table, if a matching item is found, the interest packet is forwarded according to the port of the matching item, and at the same time, the content name field in the current interest packet is added to the PIT table, and the process is ended.

(e) If no match is found, the data can not be found, and the data packet is discarded, and the process is finished.

(2) When the router receives the data packet, the processing process is consistent with the original NDN, and the NDN-PR does not modify the data packet, so that when the router receives the data packet, the data packet is returned according to the PIT table, and meanwhile, the corresponding content item of the PIT table is deleted.

(3) When the notification packet arrives at the router, the forwarding flow chart is shown in fig. 7.

(a) Checking whether the survival time of the notification packet is 0 or not, and if so, directly discarding the data packet.

(b) If the notification destination address in the notification packet is the router, the router updates the RT table of the router, if the content name in the packet exists in the RT table, the position in the RT table is changed into the new position name in the notification packet, if the content name does not exist, the entry is added in the RT table, and the content name and the new position name are respectively filled. If there is a match indicating that the node is a node before the content producer moved, there may be a large number of interest packets in the network that are addressed to the location requesting the content, and therefore the route needs to keep a copy of the redirection table. Meanwhile, in order to enable a content consumer to know that the original content has a position offset more quickly, the redirection information should be stored in a node closer to the user, so that after updating its RT table, the router needs to send a position change packet to a position closer to the content consumer. The router generates a position change packet, fills the notification packet with the content name and the new position name in the notification packet, and then forwards the notification packet, wherein the forwarding process is similar to the process of receiving a data packet by the router and will be expressed in the following process of receiving the position change packet.

(c) And searching whether the notification destination address and the content name field in the FIB table have a matching item, if so, subtracting 1 from the survival time of the router, and then forwarding the notification packet according to the FIB table.

(4) When the router receives the location change packet, the process is similar to the Data packet transmission process, and the NF packet can be forwarded to the content consumer using the PIT table, and the forwarding flowchart is shown in fig. 8.

(a) If the same content name as the location change packet is found in the RT table, the location in the RT table is changed to the new location name in the LC packet, and then a jump is made to c.

(b) If the corresponding content name is found in the RT table, the corresponding entry is created directly and then jumps to c.

(c) If the corresponding content name is found in the PIT table, the packet is forwarded from the interface corresponding to the PIT table, and the entry in the PIT table is deleted, the arrival of the packet already indicates the expiration of the request in the PIT, and the purpose is to ensure that the forwarding of the LC packet does not generate a loopback (each forwarding needs to consume the entry in the PIT table, so the forwarding process does not generate a loopback).

(5) When the position change packet reaches the content consumer, the content consumer immediately reconstructs the interest packet according to the position change packet and sends the interest packet out, and the position name of the interest packet is filled with the new position name and sent out from the interface.

Example 1:

(1) experimental Environment

The experimental environment is shown in table 1:

table 1 experimental configuration table

(2) Experimental protocol

Experiment 2 different network topologies were chosen for testing, one being a tree network of 31 nodes and the other being a ring network of 16 nodes, each topology being tested 100 times. In the experiment, a CS table of the router is set not to cache data, the data receiving time delay and the control packet transmission time delay of the NDN-PR algorithm and the home routing algorithm OPRA under the same condition are compared, and the advantages of the NDN-PR algorithm are analyzed. The data receiving delay refers to the time required for receiving corresponding data after a content consumer sends an interest packet, the time can reflect communication delay and path length, the shorter the data transmission path, the fewer the routes required for caching the data, therefore, the length of the data transmission path can indicate the size of cache redundancy, the control packet transmission delay refers to the time required for a control packet from sending to finishing of the whole control flow, the control packet is redundant information for a network, and the time can indicate the amount of redundant information in the network.

Under the tree topology structure, a network similar to the network shown in fig. 9 is constructed, a content consumer is connected with the top node, a content producer is initially connected with the leaf node at the leftmost side, the network delay from the node to the adjacent node in the network is 1 millisecond, the content producer moves to the node at the right side every 5 seconds until moving to the rightmost node, and the content consumer continuously requests content in the process. In the simulation experiment, the average data receiving time delay and the average control packet transmission time delay within 5 seconds are mainly compared with the continuous movement of a content producer.

The ring topology is as in fig. 10, a network with a next graph of content consumer locations is constructed as in the graph, content production is initially connected to the nodes to the left of the content consumer, and then the content producer moves to its next route counterclockwise every 5 seconds, with the content consumer continually requesting content. In a simulation experiment, the average data receiving time delay within every 5 seconds under the network topology structure is mainly compared.

(3) Analysis of Experimental results

The abscissa of fig. 11 is time and the content producer moves every 5 seconds, so the abscissa mainly represents the location and the ordinate represents the network delay of the average received data from the time when the content consumer sends a package of interest to the time when the corresponding data package is received. As can be seen from the figure, as the content producer moves, the network delay increases under the routing policy of the OPRA algorithm, and the delay under the NDN-PR algorithm remains almost unchanged. This is because, in the routing strategy adopting the OPRA algorithm, whenever the content producer moves, the home node is informed of new location information, each time the content consumer requests content, the content consumer needs to redirect the interest packet to the home node, on the network topological graph, when the data packet returns from the new position, the transmission path of the data packet is shortened due to the intersection with the original request path, but the data packet is not transmitted in the shortest path, so the network delay is continuously increased, the NDN-PR algorithm proposed by the present invention uses a redirection-based approach, after the arrival of a location change package, the content consumer's follow-up requests can be sent directly to the new location in the shortest path, since the shortest distance between the content consumer and the content producer is the height of the tree in this network topology, the transmission path length and thus the network latency remain almost constant. The path length is closely related to the network delay and the cache utilization rate, and a shorter path means less cache redundancy and higher cache utilization rate, so that the experiment can show that the NDN-PR algorithm provided by the invention can ensure smaller cache redundancy.

Fig. 12 is a comparison graph of average transmission delay of control packets in a tree topology, and it can be seen that the control overhead of the OPRA algorithm is first smaller than that of the NDN-PR, but the control overhead of the OPRA algorithm is continuously increased with the continuous movement of content producers. The reason is that the OPRA algorithm is based on a home routing, and when the moving times of a content producer are less, the content producer is closer to a home node, so that the transmission path of a control packet is shorter and the transmission delay of the control message is shorter than that required in the NDN-PR algorithm provided by the invention, but as the content producer continuously moves, the content producer is farther from the home routing, the transmission distance of the control packet is also continuously increased, and the transmission delay of the control message gradually exceeds the NDN-PR algorithm provided by the invention. For the NDN-PR algorithm proposed by the present invention, the control delay of the algorithm is in a stable state, and for the movement of the content producer, the transmission path of the control packet is always transmitted from the new location to the last location to the content consumer, and the path length is kept stable under this condition.

Fig. 13 is a comparison graph of average data receiving delay in a ring topology, in the previous stage of movement, since the home route is between the shortest distance of data from the content producer to the content consumer, the path is not increased by the strategy of OPRA mode, and when the content producer moves half the distance of the ring network, the data packet is transmitted from the opposite direction according to the routing strategy, which results in the need of increasing the path length. The NDN-PR algorithm provided by the invention does not generate the effect of path growth in the moving mode, so that the NDN-PR algorithm provided by the invention can show good effect in a ring network topology.

Example 2:

the NDN-PR is shown in a diagram mode aiming at two important scenes, so that the data transmission path is optimal while the service is kept uninterrupted in the moving process of a content producer, and the cache redundancy is reduced. The network topologies for both scenarios are shown in fig. 14. The process of expression is the content producer moving from location B to location C.

The first scenario is that the interest packet reaches the original access location R7 first, and then the notification packet reaches the router R7 from the router R6, as shown in fig. 15. When the content producer is also connected to the R7 router, the content consumer sends an interest packet for the content M request, the content location in the interest packet is identified as the location of R7, the interest packet arrives at R7, and the PIT table in R7 records the arrival port I of the content M, which is shown by arrow 1 in the figure; the content producer leaves the R7 router and arrives at the location C, the content producer accesses the router R6 at this time, the content producer sends a notification packet to notify that the router where the content is located has been changed to R6, and sends the notification packet to the original access router R7, the notification arrives at R7, and the process is as shown by an arrow 2 in the figure; after receiving the notification packet, the R7 updates the RT table, where the current position of the content M is recorded in the table as the position of the R6 router, the R7 generates and forwards a position change packet, the R7 finds the arrival port I of the content M in the PIT table, forwards the position change packet from the I port, and deletes the corresponding entry in the PIT table at the same time, and the position change packet is forwarded along R7-R2-R1-N, which is shown by an arrow 3 in the figure; when the position change package reaches the content consumer N, the content consumer reconstructs an interest package according to the position change package, the name of the position of the interest package is R6, the interest package is forwarded to the content producer along the direction of N-R1-R4-R6-P, and the process is shown by an arrow 4 in the figure; the content producer delivers the data packet to the content consumer in the reverse direction of interest packet delivery.

The second scenario is that the notification package arrives at R7 first, and then the interest package issues the request interest package to the original location, as shown in FIG. 16. The content producer moves from the position B to the position C, when the position C is reached, the content producer sends out a notification packet, the notification packet is filled with a content name M and a current position R6 and then is sent to the R7, the R7 receives the notification packet, the R7 updates an RT table according to the notification packet, and a new position R6 of the content is recorded in the RT table, because the PIT table does not have an item corresponding to the content M, the position change packet cannot be forwarded, and the process is shown by an arrow 1 in the figure; the content consumer sends out a request interest package for content M, which follows the path N-R1-R2-R7 to the R7 router, the process being shown by arrow 2; when the router R7 receives the interest packet of the content M, an RT table is searched, the corresponding position of the content M is found to be R6 different from R7 in the interest packet in the RT table, the R7 generates a position change packet according to the RT table, the position change packet is filled with a content name and a new position R6 and then is sent to the router R2, the transmission path of the position change packet is R7-R2-R1-N, and the process is shown by an arrow 3 in the figure; the content consumer immediately resends the interest package after receiving the location change package, and sends out the interest package with the location of R6 as the location of the content in the interest package, and the interest package reaches the content producer along N-R1-R4-R6-P, and the process is shown by arrow 4 in the figure. The content producer delivers the data packet to the content consumer in the reverse direction of interest packet delivery.

The present embodiment describes the processing flow of the NDN-PR for two scenarios, and the NDN-PR can correctly process whether the interest packet arrives at the original access point first or the notification packet arrives at the original access point first, so the NDN-PR is a robust routing policy. In both cases, the packet transfer path is P-R6-R4-R1-N, which is the shortest path for the packet to travel to the content consumer, and the NDN-PR algorithm has the property that the packet transfer path is the shortest. Shorter paths for packet delivery require fewer routers to buffer the data, and thus shorter data transmission paths represent shorter buffer redundancy, which NDN-PR may have than other routing strategies. In addition, fig. 16 is the first time the request is processed after the content producer moves from location B to location C, because the mobile feedback mechanism is introduced, the path is relatively long, but thereafter, the routers R1, R2, R7 and the content consumer all have cached the new location of the content, therefore, when the content consumer needs to request the content again, the location of the content can be directly indicated as R6, so that it can be ensured that all subsequent requests are transmitted by the shortest path between the interest packet and the data packet. After passing through the feedback mechanism, if any other host wants to request the same content, the adjacent router can directly obtain the position change packet and retransmit the request. For example, a new content consumer requesting the same content, which also accesses router R1, when it sends a request to router R1, R1 immediately returns a change of location packet to the content consumer, which may be 1 more hop, and subsequent requests are communicated in the best path. The higher the content popularity of the mobile content producer, the better the effect that this approach will yield.

Claims

1. A redirection-based information center network route optimization method is characterized by comprising the following steps:

(4) adding a redirection table, wherein the redirection table comprises two fields of a content name and a position;

step two, defining a forwarding strategy

(1) When an interest packet arrives at the router, assuming that the arrival port is I, the router will sequentially check the CS table, the redirection table, the PIT table and the FIB table, and then:

(b) if the name of the content of the interest packet is not found in the CS table, comparing the name of the content of the interest packet with the name of the content of the redirection table, if the name of the content of the interest packet is matched with the name of the location of the interest packet, if the name of the location of the interest packet is not consistent with the name of the location of the interest packet, indicating that the current interest packet can not be fed back at the requested location in the packet, and the location of the data is moved, constructing a location change packet to notify a content consumer, filling the new location name field with the location field in the table, filling the name of the content in the location change packet with the name of the content in the packet, then sending the location change packet from a port;

(c) if the matched content name is not found in the redirection table, or the content name and the position in the interest packet are consistent with those in the redirection table, which indicates that the current interest packet neither needs to be redirected nor finds a cache locally, the PIT table is searched at the moment, if an entry corresponding to the content name is found in the PIT, the arrival port I of the interest packet is added into the matched PIT entry, the interest packet is discarded, and the process is finished;

(3) when the notification packet arrives at the router, there are:

(b) if the notification destination address in the notification packet is the router, the router updates the redirection table of the router, if the redirection table has the content name in the packet, the position in the redirection table is changed into a new position name in the notification packet, if the redirection table does not have the content name in the packet, the redirection table is added with the item, and the content name and the new position name are respectively filled; if the match in item (b) indicates that the node is a node before the content producer moves, there may also be a large number of interest packets in the network that are sent to the location requesting content, and the route saves a copy of the redirection table while saving redirection information at nodes closer to the user; after updating the redirection table of the router, the router sends a position change packet to a position closer to a content consumer;

(4) when the router receives the position change packet, the notification packet is forwarded to the content consumer by using the PIT table;

2. The redirection-based information centric network routing optimization method according to claim 1, wherein in the first step, the specific step of the step (4) is as follows:

(a) if the same content name as the position change packet is found in the redirection table, changing the position in the redirection table into a new position name in the position change packet, and then jumping to (c);

(b) if the corresponding content name is found in the redirection table, directly creating a corresponding entry, and then jumping to (c);

(d) if the corresponding content name is not found in the PIT table, the position change packet is directly discarded.