a classified multi-suffix trie for ip lookup and update author: sun-yuan hsieh, ying-chi yang...
TRANSCRIPT
A Classified Multi-Suffix Trie for IP Lookup and Update
Author:Sun-Yuan Hsieh, Ying-Chi YangPublisher:IEEE TCPresenter: Jia-Wei Yo
Date:2011/10/12 1
Introduction• Propose a trie-based data structure called Classified Multi-
Suffix Trie (CMST) for designing dynamic router-tables.
• Each node can store more than one prefix and can return the longest matching prefix immediately when it is found in some internal node.
• Also propose a data structure called the Partitioning Classified Multi-Suffix Trie (PCMST) to reduce the height of a trie and expedite router-table operations.
• Two proposed data structures can be applied to both IPv4 and IPv6 routing databases.
2
CMST• A k-stride Classified Multi-Suffix Trie (k-CMST) contains two
types of nodes, a major node (m-node) and a secondary node (s-node)
• An m-node that has children is called an internal m-node, and an m-node without children is called an external m-node.
• An m-node whose stride is k has children corresponding to the possible values for the k used bits.
5
6
1. (): can be ε or a suffix, such that if (v) ≠ ε, then len((v)) > k. Port() output port of
(v) = ε, Port() = -1.
2. store output port with the length of suffix is equal to k. Otherwise , let 3. (): 0 ≤ t(v) ≤ is the number of suffixes stored in v.
4. c(): 0 ≤ c(v) ≤ is the number of (v)s with (v) −1.
5. s_pointer(): a pointer that points to a prefix tree PT comprised of s-nodes. which are used to store some suffixes q with 1 ≤ len(q) < k
PCMST
14
Set as the length of the shortest prefix in the given router table.=> Avoid duplicate storage of the same prefix in k-PCMST