이메일뉴스레터솔루션 “더좋은뉴스레터를더많은사람에게연결합니다.” · 이메일마케팅자동화전략수립과실행컨설팅제공 참고 고객여정에따른이메일마케팅자동화전략수립,
Packet Classification on Multiple Fields 참고 논문 : Pankaj Gupta and Nick McKeown SigComm 1999.
-
Upload
ethan-weaver -
Category
Documents
-
view
225 -
download
1
Transcript of Packet Classification on Multiple Fields 참고 논문 : Pankaj Gupta and Nick McKeown SigComm 1999.
Packet Classification on Multiple Fields
참고 논문 : Pankaj Gupta and Nick McKeownSigComm 1999
2
IP Lookup
Longest-prefix address lookup
Rule: Each Prefix
Action: Next hop Classifier: Forwarding table
3
Outline
Packet Classification Application, Information,
Characteristics
Design GoalPrevious WorkRecursive Flow Classification (RFC)
4
Packet classification(Application)
Packet Filtering Deny all traffic from ISP3
destined to E2
Accounting & Billing Treat all video traffic to
E1 as highest priority and perform accounting for the traffic sent this way
5
Packet classification(Application)
6
Packet Header
http://vulcan.ee.iastate.edu/~dougj/class/580/index.htm
7
Example
8
Example (Cont.)
9
Definition of Packet Classification
Each rule Specifies a class Based on criterion on F fields Associates with an identifier, classID i-th component of the rule R, R[i]
A regular expression on the i-th filed of the packet header
10
Characteristics of P-C
793 packet classifiers 101 different ISP and enterprise networksTotal 41505 rules? Data representative? Conclusion: Trivial or non-trivial?
11
Distribution of total number of rules per classifier
12
Characteristics 1
The classifiers do not contain a large number of rules. 0.7% of the classifiers contain more
than 1000 rules Mean number: 50 rules
13
Characteristics 2
The syntax allows a maximum of 8 fields to be specified: Source/destination Network-Layer
address(32-bits) Source/destination Transport-layer
port number(16-bits for TCP/UDP) Type-of-service field(8-bits) Protocol field (8-bits) Transport-Layer protocol flags(8-bits)
14
Characteristics 3-4
Transport-Layer protocol field is restricted to a small set of values: TCP, UDP, ICMP, IGMP, (E)IGRP, GRE
and IPINIP or wildcard
Transport-layer fields Many (10.2%) are range
specifications
15
Characteristics 5-6
14% of all the classifiers had a rule with a non-contiguous mask.Many different rules share a number of field specifications.
16
Characteristics 7
Redundant Backward redundancy
Rule T appears earlier than Rule R, and R is a subset of T.
Forward redundancy Rule T apperas after R
R is a subset of T R, T have the same action Rules inbetween R and T
The same action Disjoint from R.
8% of the rules were redundant.
17
Goals
Fast enough Matching on arbitrary fieldsSupport general classification rules Prefixes, operators(like range, less than,
greater than…) and wildcards.
Suitable for software and hardware implementationMemory efficientScalabilityFor steady classifier
18
Previous Work
Sequential evaluationsGrid of TriesCrossproductingBit-level parallelismTCAM
19
Abstract
The point location problem in multidimensional spaceFind the enclosing region of a point, given a set of regions.Complexity O(logn) in time with O(nF) space O(logF-1n) time with O(n) space
20
Structure of classifiers
21
Overlapping is small
For the biggest classifier with 1734 rules, the number of distinct overlapping regions in four dimensions to be 4316, compared to a worst possible case of approximately 1013.
22
Recursive Flow Classification
23
Chunks of Packet header
24
Packet flow in RFC
25
Phase number =3
26
Phase number =4
27
Select Phase number
Combine those chunks together which have the most “correlation”.Combine as many chunks as possible without causing unreasonable memory consumption.Best case: P=3 Tree B P=4 Tree A
28
Performance (Storage requirement for
P=2)
29
Performance (Storage requirement for P=3)
30
Performance (Storage requirement for P=4)
31
Preprocess Time
32
Hardware implementation
33
Larger classifiers IConcatenating the classifiers belonging to the
same network.
34
Larger classifiers II
Concatenate all the classifiers of a few (up to ten) different networks. RFC frequently runs into storage
problems for classifiers with more than 6000 rules.
35
Variations
Process a larger number of fields in each packet header.Use available fast lookup algorithmsUse Adjacency group
36
Adjacency Groups
Two rules (R, S)are considered adjacent R appears first The same Action All but one field have the same
specification All rules in between R and S
Either have the same action Disjoint from R
37
An example
38
Storage (Adjacency groups)
39
Comments
Trade off? Memory, Speed, Dynamic Change, etc
Application and Demand orientedFurther discussion? [email protected]
Thank you!