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In VINI Veritas Realistic and Controlled Network Experimentation. Andy Bavier Nick Feamster* Mark Huang Larry Peterson Jennifer Rexford. Princeton University *Georgia Tech. Modified and presented by Arjumand Younus and Moonyoung Chung. Outline. Motivation - PowerPoint PPT Presentation
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In VINI VeritasRealistic and Controlled Network Experimentation
Andy Bavier Nick Feamster* Mark Huang
Larry Peterson Jennifer Rexford
Princeton University *Georgia Tech
Modified and presented by Arjumand Younus and Moonyoung Chung
Outline
Motivation Scientific Value and
Importance of VINI Fundamental
Philosophy of VINI Design Requirements
Strategy for building VINI
PL-VINI: prototype on PlanetLab
Experimental results Conclusion
2
Motivation - How to Validate an Idea?
Fixed, shared among many experiments Runs real routing software Exposes realistic network conditions Gives control over network events Carries traffic on behalf of real users
Simulation
Emulation
Small-scaleexperiment
Livedeployment
VINI
3
Realism has Scientific Value
The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ (I found it!) but ‘That’s funny …’ -- Isaac Asimov
Discover unanticipated interactionsCan only simulate / emulate known propertiesBuild richer models
Test robustness and scalability of ideas
4
Fundamental Philosophy “Controlled Realism”
Control: Reproduce results Methodically change or
relax constraints
Realism: Long-running services
attract real “customers” Forward high traffic
volumes (Gb/s) Robustly handle
unexpected events
Topology
Actual network
Arbitrary, emulated
Traffic
Real clients, servers
Synthetic or traces
Network Events
Observed in operational network
Inject faults, anomalies
5
Overview
VINI requirementsFixed, shared infrastructureFlexible network topologyExpose/inject network eventsExternal connectivity and routing adjacencies
PL-VINI: prototype on PlanetLab Experimental results Conclusion
6
Fixed Infrastructure
VINI nodes embedded in Abilene7
Shared Infrastructure
Experiments given illusion of dedicated hardware8
Shared Infrastructure
Experiments given illusion of dedicated hardware9
Flexible Topology
VINI supports arbitrary virtual topologies10
Flexible Topology
VINI supports arbitrary virtual topologies11
Network Events
VINI can inject network failures12
Network Events
VINI can expose network failures (coming soon)
real link fails
virtual link fails
13
External Connectivity
s
c
Experiments can carry traffic for real end-users14
External Routing Adjacencies
s
c
BGP
BGP
BGP
BGP
Experiments can participate in Internet routing15
PlanetLab VINI
Build VINI from PlanetLab, a global testbed for distributed servicesBegun in 2002700 nodes at 336 sites in 35 countries 600 projects and 2500 researchersServes 3-4 TB/day to ~1M clients
MyPLC: PlanetLab software distributionAnyone can run their own private PlanetLab
16
PL-VINI: Prototype on PlanetLab
PlanetLab: testbed for planetary-scale services Simultaneous experiments in separate VMs
Each has “root” in its own VM, can customize
Can reserve CPU, network capacity per VM
Virtual Machine Monitor (VMM)(Linux++)
NodeMgr
LocalAdmin
VM1 VM2 VMn…PlanetLab node
17
Resource Isolation
Issue: Forwarding packets in user space PlanetLab sees heavy use CPU load affects virtual network performance
Property Depends On Solution
Throughput CPU% received PlanetLab provides CPU reservations
Latency CPU scheduling delay
PL-VINI: boost priority of packet forward process
18
PL-VINI: Prototype on PlanetLab
Enable experiment: Internet In A Slice XORP open-source routing protocol suite (NSDI ’05) Click modular router (TOCS ’00, SOSP ’99)
Clarify issues that a VINI must address Unmodified routing software on a virtual topology Forwarding packets at line speed Illusion of dedicated hardware Injection of faults and other events
19
Synthesis of Software Components to enable PL-VINI XORP – Open Source Routing Protocol Suite especially
developed for network research community. [9, NSDI ’05]
Click – Software Architecture for Building Flexible and Configurable routers [10]
UML – Linux-Kernel running as regular Linux-User-Process without Root-Privileges.
OpenVPN – Open source SSL VPN solution.
20
XORP: Control Plane
BGP, OSPF, RIP, PIM-SM, IGMP/MLD
Goal: run real routing protocols on virtual network topologies
XORP(routing protocols)
21
User-Mode Linux: Environment
Interface ≈ network PlanetLab limitation:
Slice cannot create new interfaces
Run routing software in UML environment
Create virtual network interfaces in UML
XORP(routing protocols)
UML
eth1 eth3eth2eth0
22
Click: Data Plane
Performance Avoid UML overhead Move to kernel, FPGA
XORP(routing protocols)
UML
eth1 eth3eth2eth0
Click
PacketForwardEngine
Control
Data
23
Click: Data Plane
Performance Avoid UML overhead Move to kernel, FPGA
XORP(routing protocols)
UML
eth1 eth3eth2eth0
Click
PacketForwardEngine
Control
DataUmlSwitch
element
24
Click: Data Plane
Performance Avoid UML overhead Move to kernel, FPGA
Interfaces tunnels Click UDP tunnels
correspond to UML network interfaces
XORP(routing protocols)
UML
eth1 eth3eth2eth0
Click
PacketForwardEngine
Control
DataUmlSwitch
element
Tunnel table
25
Injecting Link Failures
XORP(routing protocols)
UML
eth1 eth3eth2eth0
Click
PacketForwardEngine
Control
DataUmlSwitch
element
Tunnel table
Filters
Performance Avoid UML overhead Move to kernel, FPGA
Interfaces tunnels Click UDP tunnels
correspond to UML network interfaces
Filters “Fail a link” by blocking
packets at tunnel26
Life of a packet in IIAS
27
Experiments
MicrobenchmarksCapacityBehavior
Intra domain Route changesFailure and recovery
28
Overlay Efficiency IIAS’s user-space Click forwader vs. in-
kernel forwarding
29
Performance is bad
User-space Click: ~200Mb/s forwarding Can do a lot with 200Mb/s
20 experiments can have dedicated 10Mb/s nationwide networks
Improving performance is ongoing workAllow experiments to load custom Click
modules into the VINI kernel30
Overlay on PlanetLab on dedicated hardware (DETER) vs.
shared platform (PlanetLab) and PL-VINI
31
PL-VINI and IIAS together provide a close approximation of the underlying network’s behaviors.
Overlay on PlanetLab
32
Intra-domain Route Changess
c
1176
587 846
260
700
6391295
2095
902
548
233
1893
366
Watch OSPF route convergence on Abilene
856
33
Intra-domain Route Changess
c
1176
587 846
260
700
6391295
2095
902
548
233
1893
366
Watch OSPF route convergence on Abilene
856
34
Intra-domain Route Changess
c
1176
587 846
260
700
6391295
2095
902
548
233
1893
366
Watch OSPF route convergence on Abilene
856
35
Intra-domain Route Changess
c
1176
587 846
260
700
1295
2095
902
548
233
1893
366
Watch OSPF route convergence on Abilene
856
36
Intra-domain Route Changess
c
1176
587 846
260
700
6391295
2095
902
548
233
1893
366
Watch OSPF route convergence on Abilene
856
37
Ping During Link Failure
70
80
90
100
110
120
0 10 20 30 40 50
Pin
g R
TT
(m
s)
Seconds
Link down
38
Ping During Link Failure
70
80
90
100
110
120
0 10 20 30 40 50
Pin
g R
TT
(m
s)
Seconds
Link down
Link up
39
Ping During Link Failure
70
80
90
100
110
120
0 10 20 30 40 50
Pin
g R
TT
(m
s)
Seconds
Link down
Link up
Routes converging
40
TCP Throughput
0
2
4
6
8
10
12
0 10 20 30 40 50
Meg
abyt
es t
rans
ferr
ed
Seconds
Packet receiv ed
Link down
41
TCP Throughput
0
2
4
6
8
10
12
0 10 20 30 40 50
Meg
abyt
es t
rans
ferr
ed
Seconds
Packet receiv ed
Link down
Link up
42
TCP Throughput
0
2
4
6
8
10
12
0 10 20 30 40 50
Meg
abyt
es t
rans
ferr
ed
Seconds
Packet receiv ed
Link down
Link up
Zoom in
43
Arriving TCP Packets
2.1
2.15
2.2
2.25
2.3
2.35
2.4
2.45
17.5 18 18.5 19 19.5 20
Meg
abyt
es in
str
eam
Seconds
Packet receiv ed
Slow start
44
Arriving TCP Packets
Slow start
Retransmitlost packet
2.1
2.15
2.2
2.25
2.3
2.35
2.4
2.45
17.5 18 18.5 19 19.5 20
Meg
abyt
es in
str
eam
Seconds
Packet received
45
Arriving TCP Packets
2.1
2.15
2.2
2.25
2.3
2.35
2.4
2.45
17.5 18 18.5 19 19.5 20
Meg
abyt
es in
str
eam
Seconds
Packet receiv ed
Slow start
Retransmitlost packet
PL-VINI enables a user-space virtual networkto behave like a real network on PlanetLab
46
Conclusion
VINI: Virtual Network Infrastructure Controlled and realistic experimentation New routing, forwarding, and addressing
Initial experiment Intradomain routing convergence in XORP Later, perhaps run commercial router code?
Long term goal Shared platform for networking experiments Real user traffic and upstream ISP connections
47