Forwarding method, device and system for network nodes in named data network and storage medium

Abstract

The invention provides a forwarding method, device and system for network nodes in a named data network and a storage medium. The forwarding method comprises an FIB, wherein the FIB comprises a hash table and a prefix tree; for any name stored in the table, all true prefixes of the name have corresponding table entries in the table, the process of checking whether the prefixes exist and adding thecorresponding auxiliary table entries is called FIB reconstruction; in the reconstructed FIB, the table entries are divided into real table entries and non-real table entries, and the non-real tableentries are divided into virtual table entries and semi-virtual table entries. The beneficial effects of the invention are that: an FIB forwarding architecture supporting random search and a related algorithm are realized; the problem of backtracking and the problem of outdated entries are thoroughly solved, and experimental evaluation shows that the time overhead of the algorithm is hardly influenced, so that the high efficiency and superiority of the random search algorithm are ensured, and an important foundation is laid for designing an efficient NDN forwarding architecture and thoroughlysolving the problem of expandability of the NDN.

Description

technical field [0001] The invention relates to the technical field of the Internet, in particular to a forwarding method, device, system and storage medium for network nodes in a named data network. Background technique [0002] Information Centric Networking (ICN), including Content Centric Networking (CCN) and Named Data Networking (NDN), is a new Internet architecture designed to solve the bottleneck of the current IP protocol. What is mentioned in this invention is mainly its NDN branch, and NDN will be referred to as the content-centric network in the following. In NDN, the network cares more about the data itself than the location of the data. Through the decoupling of content and specific locations, as well as appropriate forwarding and caching strategy design, NDN realizes multi-path data transmission through an intelligent forwarding plane, and reduces data request delay through caching in the network, thereby realizing Efficient and reliable information distribut...

AI Technical Summary

Problems solved by technology

However, the name-oriented forwarding mode also has its drawbacks: as the network scale expands, the performance of the NDN forwarding plane tends to degrade seriously, including the rapid increase of forwarding delay, packet congestion, and large memory usage. and many more

[0005] 1. The name-oriented forwarding plane uses the name as the search key, and the NDN name has unbounded length and variable styles. Therefore, it is often difficult to apply various optimization algorithms based on regular IP addresses; at the same time, the traditional linear The search algorithm has a time overhead proportional to the expected length of the name, and it is difficult to achieve good results for NDN names that are much longer than IP addresses

The above reasons lead to a large delay in the query process

[0006] 2. Since the objects referred to are more subtle, the number of NDN names is far greater than the number of IP addresses, resulting in the fact that the FIB of NDN often has an extremely large scale

[0015] Disadvantage of background technology 1: In the case of a query hit, this method relies on a more time-consuming linear search. Since the time overhead of the linear search is proportional to the expected length of the query string, in the face of an NDN name with no upper bound on the length, the There is still a large room for optimization in the algorithm

[0020] The second shortcoming of background technology: the above-mentioned binary query scheme, and many similar random search algorithms

[0022] Disadvantages of background technology 3: similar to background technology 2, there are so-called backtracking problems (BacktrackingProblem) and outdated entry problems (Outdated Entry Problem)

[0023] Backtracking problem: In the above-mentioned binary query process, when the algorithm body is executed, if the prefix of the last HIT is a virtual table entry, the FIB cannot judge whether there is forwarding information corresponding to the name to be queried. Therefore, the algorithm needs Go to the prefix of the last hit and re-do the linear search

However, its LPM " / c1" exists in the table, resulting in a False Negative error

In the traditional IP protocol, the forwarding algorithm solves this problem by a backtracking lookup, that is, going to the prefix of the last hit (here " / c1 / c2 / c3") and performing a linear lookup, however, as mentioned above , the name in the content network is unbounded and much longer than the length of the IP address, so this method is difficult to apply to the NDN implementation

[0025] Obsolete entry problem: In the existing random search scheme, it is difficult to delete obsolete virtual entries in time. In the above example, if " / c1 / c2 / c3 / c4" is deleted, then " / c1 / c2 / " and " / c1 / c2 / c3" lose their necessity and should be deleted in time to save storage overhead

However, due to the diversity of NDN identifiers, unless the entire table is traversed, it is difficult for FIB to determine whether an auxiliary entry has other entries inherited from it in the table

Therefore, the accumulation of obsolete auxiliary entries will also cause a lot of memory waste, affecting the overall performance of the network

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