1/25 generic and automatic address configuration for data center networks 1 kai chen, 2 chuanxiong...
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Generic and Automatic Address Generic and Automatic Address Configuration for Data Center Configuration for Data Center
NetworksNetworks
11Kai ChenKai Chen, , 22Chuanxiong Guo, Chuanxiong Guo, 22Haitao Wu, Haitao Wu, 33Jing Yuan, Jing Yuan, 44Zhenqian Feng, Zhenqian Feng, 11Yan Chen, Yan Chen, 55Songwu Lu, Songwu Lu, 66Wenfei WuWenfei Wu
11Northwestern University, Northwestern University, 22Micrsoft Research Asia, Micrsoft Research Asia, 33Tsinghua, Tsinghua, 44NUDT, 5UCLA, 6BUAA
SIGCOMM 2010, New Delhi, IndiaSIGCOMM 2010, New Delhi, India
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Motivation Address autoconfiguration is desirable in networked
systemsManual configuration is error-prone
50%-80% network outages are due to manual configurationDHCP for layer-2 Ethernet autoconfiguration
Address autoconfiguration in data centers (DC) has become a problemApplications need locality information for computationNew DC designs encode topology information for routingDHCP is not enough - no such locality/topology information
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Research Problem
Given a new/generic DC, how to autoconfigure the addresses for all the devices in the
network?
DAC: data center address autoconfiguration
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OutlineMotivationResearch ProblemDACImplementation and ExperimentsSimulationsConclusion
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DAC Input Blueprint Graph (Gb)
A DC graph with logical IDsLogical ID can be any formatAvailable earlier and can be
automatically generated
Physical Topology Graph (Gp)A DC graph with device IDsDevice ID can be MAC addressNot available until the DC is
built and topology is collected
(a). Blueprint:Each node has a logical ID
(b). Physical network topology:Each device has a device ID
10.0.0.3
00:19:B9:FA:88:E2
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DAC System Framework
Physical Topology Collection
Device-to-logical ID Mapping
Logical ID Dissemination
Malfunction Detection
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Two Main Challenges Challenge 1: Device-to-logical ID Mapping
Assign a logical ID to a device, preserving the topological relationship between devices
Challenge 2: Malfunction DetectionDetect the malfunctioning devices if the physical topology is
not the same as blueprint (NP-complete and even APX-hard)
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Roadmap
Physical Topology Collection
Device-to-logical ID Mapping
Logical ID Dissemination
Malfunction Detection
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Device-to-logical ID Mapping How to preserve the topological relationship?
Abstract DAC mapping into the Graph Isomorphism (GI) problem
The GI problem is hard: complexity (P or NPC) is unknownIntroduce O2: a one-to-one mapping for DAC
O2 Base Algorithm and O2 Optimization Algorithm Adopt and improve techniques from graph theory
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O2 Base Algorithm Gb: {l1 l2 l3 l4 l5 l6 l7
l8}
Gp: {d1 d2 d3 d4 d5 d6 d7 d8}
Gb: {l1} {l2 l3 l4 l5 l6 l7 l8}
Gp: {d1} {d2 d3 d4 d5 d6 d7 d8}
Gb: {l1} {l5} {l2 l3 l4 l6 l7 l8}
Gp: {d1} {d2 d3 d5 d7} {d4 d6 d8}
Decomposition
Refinement
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O2 Base Algorithm Gb: {l1 l2 l3 l4 l5 l6 l7 l8}
Gp: {d1 d2 d3 d4 d5 d6 d7 d8}
Gb: {l5} {l1 l2 l3 l4 l6 l7 l8}
Gp: {d1} {d2 d3 d4 d5 d6 d7 d8}
Gb: {l5} {l1 l2 l7 l8} {l3 l4 l6 }
Gp: {d1} {d2 d3 d5 d7} {d4 d6 d8}
Gb: {l5} {l1 l2 l7 l8} {l6} {l3 l4}
Gp: {d1} {d2 d3 d5 d7} {d6} {d4 d8}
Decomposition
Refinement
Refinement
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O2 Base Algorithm
Gb: {l5} {l6} {l1 l2} {l7 l8} {l3 l4}
Gp: {d1} {d6} {d2 d7} {d3 d5} {d4 d8}
Gb: {l5} {l6} {l1} {l2} {l7 l8} {l3 l4}
Gp: {d1} {d6} {d2} {d7} {d3 d5} {d4 d8}
Gb: {l5} {l6} {l1} {l2} {l7} {l8} {l3} {l4}
Gp: {d1} {d6} {d2} {d7} {d3} {d5} {d4} {d8}
Refinement
Decomposition
Decomposition &
Refinement
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O2 Base AlgorithmO2 base algorithm is very slow
for 3 problems:P1: Iterative splitting in
Refinement: it tries to use each cell to split every other cell iteratively Gp: π1 π2 π3 …… πn-1 πn
P2: Iterative mapping in Decomposition: when the current mapping is failed, it iteratively selects the next node as a candidate for mapping
P3: Random selection of mapping candidate: no explicit hint for how to select a candidate for mapping
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O2 Optimization AlgorithmHeuristics based on DC topology features
Sparse => Selective Splitting (for Problem 1)Symmetric => Candidate Filtering via Orbit (for
Problem 2)Asymmetric => Candidate Selection via SPLD
(Shortest Path Length Distribution) (for Problem3)
We propose the last one and adopt the first two from graph theory
R1: A cell cannot split another cell that is disjoint
with itself.
R2: If u in Gb cannot be mapped to v in Gp, then all nodes in the same orbit with u cannot be
mapped to v either. R3: Two nodes u, v in Gb, Gp cannot be mapped to each other if have different
SPLDs.
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Speed of O2 Mapping
12.4 hours
8.9 seconds
8.9 seconds
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Roadmap
Physical Topology Collection
Device-to-logical ID Mapping
Logical ID Dissemination
Malfunction Detection
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Malfunction Detection Types of Malfunctions
Node failure, Link failure, Miswiring
Effects of MalfunctionsO2 cannot find device-to-logical
ID mapping
Our GoalDetect malfunctioning devices
Problem ComplexityAn ideal solution
1.Find Maximum Common Subgraph (MCS) between Gb and Gp say Gmcs
2.Remove Gmcs from Gp => the rest are malfunctionsMCS is NP-complete and even APX-hard
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Practical Solution Observations
Most node/link failures, miswirings cause node degree changeSpecial, rare miswirings happen without degree change
Our IdeaDegree change case: exploit the degree regularity in DC
Devices in DC have regular degrees (common sense)No degree change case: probe sub-graphs derived from anchor
points, and correlate the miswired devices using majority voting Select anchor point pairs from 2 graphs
probe sub-graphs iteratively, stop when k-hop subgraphs are isomorphic but (k+1)-hop are not, increase the counters for k- and (k+1)- hop nodes
Output node counter list: high counter => high possible to be miswired
Isomorphic
1
2
k+1
k
1
2
k
k+1
Isomorphic
… …Isomorphic
Non-Isomorphic
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Simulations on Miswiring Detection
Over data centers with tens of thousands of deviceswith 1.5% nodes as anchor points to identify all hardest-to-
detect miswirings
1.5%
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Roadmap
Physical Topology Collection
Device-to-logical ID Mapping
Logical ID Dissemination
Malfunction Detection
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Basic DAC Protocols CBP: Communication Channel Building
ProtocolTop-Down, from root to leaves
PCP: Physical Topology Collection ProtocolBottom-Up, from leaves to root
LDP: Logical ID Dissemination ProtocolTop-Down, from root to leaves Logical
DAC Manager
DAC manager:1. handle all the
intelligences 2. can be any server in the
network
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Implementation and ExperimentsOver a BCube(8,1) network with 64 servers
1. Communication Channel Building (CCB)
2. Transition time3. Physical Topology Collection (TC)4. Device-to-logical ID Mapping5. Logical IDs Dissemination (LD)The total time used: 275
milliseconds
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SimulationsOver large-scale data centers (in milliseconds)
46 seconds for the DCell(6, 3) with 3.8+
million devices
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SummaryDAC: address autoconfiguration for generic data
center networks, especially when the address is topology-awareGraph isomorphism for address configuration
275ms for a 64-sever BCube, and 46s for a DCell with 3.8+ million devices
Anchor point probing for malfunction detectionwith 1.5% nodes as anchor points to identify all hardest-to-
detect miswirings
DAC is a small step towards the more ambitious goal of automanagement of the whole data centers
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Q & A? Thanks!