A Multi-dimensional Packet Classification Algorithm Based on Hierarchical All-match B+ Tree Author: Gang Wang, Yaping Lin*, Jinguo Li, Xin Yao Publisher: 2013 IEEE International Conference on High Performance Computing and Communications (HPCC) Presenter: Chih-Hsun Wang Date: 2014/4/22 Department of Computer Science and Information Engineering National Cheng Kung University, Taiwan R.O.C.

Introduction National Cheng Kung University CSIE Computer & Internet Architecture Lab 2 The previous trie-based hierarchical search structure suffers from backtracking and address length. We develop an all-match prefix tree (APT) based on B + tree and propose a two-stage hierarchical search structure HAPT. By performing multi-way search without backtracking, the proposed classification algorithm can classify packets in O(log m N) and update rules in O(mlog m N) Furthermore, the proposed algorithm is suitable for both IPv4 and IPv6.

Proposed Algorithm National Cheng Kung University CSIE Computer & Internet Architecture Lab 3 All-match Prefix Tree 1)Each node x contains the following information: a) n(x), leaf(x), b) key i (x), where 1≤ i ≤ n(x), and key 1 (x) < key 2 (x) < … < key n(x) (x) 2)If x is an internal node, x contains n(x) pointers pointing to its n(x) children. Leaf nodes do not have children. 3)The first key of each node (except the root) is repeatedly stored in its parent node as the search index.

Proposed Algorithm National Cheng Kung University CSIE Computer & Internet Architecture Lab 4 All-match Prefix Tree 4)All the leaf nodes are in the same layer with the depth h. 5)The number of keys stored in nodes can be expressed with the integer m as follows. a) There are at most m/2 keys stored in each node, and at least m/2 children pointed by m/2 pointers. b) There are at most m keys stored in each node and m pointers pointing to the corresponding children

Proposed Algorithm National Cheng Kung University CSIE Computer & Internet Architecture Lab 5 All-match Prefix Tree 6)For each key key i (x) in leaf node x, there is a compress label bitmap i (x), which represents the k compressed prefixes. Where bitmap(x) is a prefix in length w. all bits of bitmap(x) are originally set to 0. When the key set of node x includes a prefix of length l, the l-th bit of bitmap(x) is set to 1.

Proposed Algorithm National Cheng Kung University CSIE Computer & Internet Architecture Lab 6

Proposed Algorithm National Cheng Kung University CSIE Computer & Internet Architecture Lab 7

Proposed Algorithm National Cheng Kung University CSIE Computer & Internet Architecture Lab 8 Hierarchical All-match Prefix Tree 1)HAPT is a data structure with two stage, where each stage is built by all-match prefix tree. 2)In the first stage, each leaf node stores n(x) keys key i (x), n(x) compress labels bitmap i (x) and n(x) pointers pointing from key i (x) to a D-APT of the second stage.

Proposed Algorithm National Cheng Kung University CSIE Computer & Internet Architecture Lab 9 Hierarchical All-match Prefix Tree 3)In the second stage, each D-APT is built by a subset φ of P DA and is attached to a leaf node x of the first stage, where the source IP prefixes stored by key i (x) and bitmap i (x) belong to the same rules with φ. 4)Each leaf nodes of the second stage stores a pointer pointing to a small ruleset ϒ, in which the rules are stored in the order as stored in bitmap i (x).

Proposed Algorithm National Cheng Kung University CSIE Computer & Internet Architecture Lab 10

National Cheng Kung University CSIE Computer & Internet Architecture Lab 11

National Cheng Kung University CSIE Computer & Internet Architecture Lab 12 Data Analysis

National Cheng Kung University CSIE Computer & Internet Architecture Lab 13 Classification Speed

National Cheng Kung University CSIE Computer & Internet Architecture Lab 14 Classification Speed

National Cheng Kung University CSIE Computer & Internet Architecture Lab 15 Memory Usage

National Cheng Kung University CSIE Computer & Internet Architecture Lab 16 Memory Usage