A Study Of Cyclone Technology
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Table of Content
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•
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•
•
Overview
Contributions
The need for time-based resource management
Cyclone technology - basic idea
Description of a Cyclone network
Clock synchronization
Data movements
Connection management
Scheduling
Adaptation layer
Fault handling
Performance
Advantages and limitations
Open issues
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Overview
•
Current networking
– event-based, on-demand resource allocation
– best effort performance
•
•
•
New classes of traffic placing stringent requirements on the communications
Time-based resource management in a synchronous manner
End-to-end coordination among network components
– no congestion, loss, jitter
– better utilization of bandwidth
• one byte header
• reduced control messages
• reduced routing information
– well-suited network environment for traffic with stringent timing requirements
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Contributions
•
Time-based networking technology
–
–
–
–
•
•
components
protocols
operations
host interface
Time-based resource management
Alternate way of managing resources in networking
– without requiring very accurate and highly synchronized clocks
– without consuming significant amount of bandwidth for handling timing variability
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Time-based Resource Management In Networking
A
B
node
node X link 1
node Z
Y
C link 2 D
Data Loss
A
t1
t2
Data Loss Prevention
t5
t3
t6
t4
A
t7
t1
t2
t8
t3
B
t6
t4
t7
t8
B
t9
t10
t9
Delay and Jitter
A
t5
t1
t2
t3
Delay and Jitter Control
t5
t4
t10
t6
t7
A
t8
t1
t2
t3
B
t5
t4
t6
t7
t8
B
t9
t10
t11
t12
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t9
t10
t11
t12
5
Cyclone Technology - Basic Idea
tA
tA+sA
tA+d
tA+sA+d
tA
tA+sA
tA+2sA
tA+3sA
tB
tB+sB
tB+2sB
...
tA+(i-1)sA
tA+isA
tA+(i+1)sA
...
tB+(j-1)sB
tB+jsB
tB+(j+1)sB
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Data Movements - Basic
Free slot list
Incoming link
Outgoing link
Slot buffer
Pointer buffer
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Data Movements
host
switch
controller
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Types Of Traffic Supported
•
•
Connection-oriented
Scheduled traffic
– data available at known time instant (temporal profile)
– resources reserved when establishing a connection
•
On-demand traffic
– source routing
– dynamic resource allocation
– possible loss of a chunk
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Description Of Cyclone Network
•
•
•
•
•
Chunk
Slot and slot time
Time tag
Period
Fixed design parameters
– the size of a chunk
– the duration of a period
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Chunk Types
marker
•
•
Three types - Control/Scheduled/On-demand
Control chunk
–
–
–
–
•
checksum
multiple sub-chunks in a chunk
connection request chunk
confirm/reject/abort/terminate chunk
pathfinder chunk
Scheduled chunk
– scheduled traffic data chunk
– scheduled traffic data acknowledgement/retransmission request chunk
•
On-demand chunk
– on-demand traffic data chunk
– on-demand traffic data acknowledgement/retransmission request chunk
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Multiple Sub-chunks In A Chunk
marker
n
subchunk
. . . subchunk
padding
checksum
512 bytes
8
8
bit marker
bit n is the number of subchunks contained;
maximum is (512-1-1-2)/b
where b is the number of bytes in a subchunk (127)
b*n bit subchunks where b is the number of bits in a subchunk
v
bit padding where (v=(512-1-1-b*n-2)*8>=0)
16 bit checksum
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Connection Request Chunk
marker source
8
bit
160 bit
160 bit
8
bit
64 bit
64 bit
16 bit
24*sbit
v
bit
16 bit
destination
ToS
start
end
s
temporal
behavior
padding
checksum
512 bytes
marker
source address (128 bit address + 32 bit port)
destination address (128 bit address + 32 bit port)
type of services
start time
end time
s is the number of temporal descriptors in this chunk
temporal behavior
padding where (v=(512-1-20-20-1-8-8-2-3*s-2)*8>=0)
checksum
marker source
8
bit
160 bit
160 bit
16 bit
24*sbit
v
bit
16 bit
destination
s
temporal
behavior
padding
checksum
512 bytes
marker
source address (128 bit address + 32 bit port)
destination address (128 bit address + 32 bit port)
s is the number of temporal descriptors in this chunk
temporal behavior
padding where (v=(512-1-20-20-2-3*s-2)*8>=0)
checksum
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Confirm/Reject/Abort/Terminate Chunk
marker
source
destination
padding
checksum
127 bytes
8
160
160
672
16
bit
bit
bit
bit
bit
marker
source address (128 bit address + 32 bit port)
destination address (128 bit address + 32 bit port)
padding (127-1-20-20-2)*2
checksum
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Pathfinder Chunk
marker source
destination
hops*
pointer**
list*
padding*
checksum*
127 bytes
8
bit marker
160
bit source address (128 bit address + 32 bit port)
160
bit destination address (128 bit address + 32 bit port)
8
bit number of hops(h)*
8
bit pointer into current hop position**
8*h*2 bit list of outgoing and incoming link identifier pair at each hop*
v
bit padding where (v=(127-1-20-20-1-1-1*h*2-2)*8>=0)*
16
bit checksum*
* recomputed at each hop on forward path
**recomputed at each hop on forward and reverse paths
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Scheduled Traffic Data and
Acknowledgement/Retransmission Request Chunk
marker
data
padding
checksum
512 bytes
8
8*d
v
16
bit
bit
bit
bit
chunk marker
data (d bytes of data)
padding where (v=(512-1-1*d-2)*8>=0)
checksum
marker source
8
160
160
16
656
16
bit
bit
bit
bit
bit
bit
destination
sequence
padding
checksum
127 bytes
marker
source address (128 bit address + 32 bit port)
destination address (128 bit address + 32 bit port)
slot sequence number for this connection
padding (127-1-20-20-2-2)*8
checksum
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On-Demand Traffic Data And
Acknowledgement/Retransmission Request Chunk
marker hop
pointer*
list
source
destination
data
padding
checksum*
512 bytes
8
bit check marker
8
bit number of hops
8
bit index into current hop information
8*h*2 bit list of outgoing and incoming link identifier pair at each hop
160
bit source address
160
bit destination address
8*d
bit data (d byte data)
v
bit padding where (v=(512-1-1-1-1*h*2-20-20-1*d-2)*8>=0)
16
bit checksum*
* recomputed at each hop
marker hops pointer*
list
source
destination
data
padding
checksum*
127 bytes
8
bit marker
8
bit number of hops(h)
8
bit index into current hop information*
8*h*2 bit list of outgoing and incoming link identifier pair at each hop
160
bit source address (128 bit address + 32 bit port)
160
bit destination address (128 bit address + 32 bit port)
8*d
bit data containing acknowledgement/retransmit request
v
bit padding where (v=(127-1-1-1-1*h*2-20-20-1*d-2)*8>=0)
16
bit checksum*
* recomputed at each hop
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Cyclone Network Model
Temporal Regulator
Non-Cyclone
Network
Cyclonode
host
Incoming
link 1
outgoing
link 1
1’
Non-Cyclone Network
Incoming
link m
outgoing
link m
m’
Backup
Incoming
link 1’
switch
Backup
Incoming
link m’
Backup
outgoing
link 1’
Backup
outgoing
link m’
controller
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Clock Synchronization
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•
•
•
Clock Adjustment At A Node
With Four Incoming Links
Markers are sent to indicate the beginning and
ending of a period
A node obtains the clock information of
upstream nodes
A local clock rate is set to the average of
incoming clock rates and its own rate
A local clock phase is set considering clock
phase information
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Connection Establishment/Termination
C
2
1
B
A
D
3
5
4
E
6
7
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Time Relationship Of Scheduling
t1
Timeline of incoming link
t2
d
t3
Timeline of outgoing link
(same speed)
Timeline of outgoing link
(slower)
Timeline of outgoing link
(faster)
t4
t3
t4
t3
t4
t1  d  t3  t 2    t 4
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Single-Pass Scheduling Approach
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•
First available slot column assignment
Assignment before reusing the buffer space
0
1
2
3
4
5
6
7
22
23
24
0
25
26
0
22
23
24
25
1
2
3
4
5
6
7
1
2
3
21
22
23
24
25
26
27
28
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4
5
6
7
Available
slot list
(2, 3, 5, 6, 7)
(3, 6, 7)
(3)
(1, 3, 4, 5)
22
Double-Pass Scheduling Approach
0
0
21
22
23
24
25
26
27
1
2
3
4
5
6
7
1
2
3
4
5
6
7
21
22
23
24
25
26
Available
slot list
(1, 2, 3, 4, 6)
(2, 3, 4)
27
28
0
1
2
3
21
22
23
24
25
26
27
28
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4
5
6
7
Available
slot list
(1, 2, 3, 4, 6)
(2, 3, 4)
23
Double-Pass Scheduling Approach
0
1
2
3
4
5
6
7
21
22
23
24
25
26
27
0
1
2
3
4
5
6
7
Available
slot list
21
22
23
(1, 2, 3, 4, 6)
24
25
26
27
28
(2, 3, 4)
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Adaptation Layer
Application Layer
•
Supports existing applications and
communications with non-Cyclone
networks
Cyclone Adaptation Layer Cyclone Interface (CAL-C)
Switch
Controller
Application Layer
TCP
CAL-A
IP
CAL-C
Network
Interface
Temporal Regulator
– Specify temporal profile for a scheduled
traffic
– Provide scheduled data chunks according
to the temporal profile specified
– Detect bit-errors
– Initiate appropriate recovery mechanisms
– Initiate command control chunks
– Detect data loss for on-demand traffic
Temporal Regulator
Cyclone Adaptation Layer Application Interface (CAL-A)
Host
Receive information from an application
and provide the appropriate information
to a temporal regulator in the form
acceptable to a Cyclone network
Host
•
Switch
Controller
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Fault Handling
•
Backup link approach
incoming
link 1
– line condition monitor
– backup link pointer
– automatic switching to backup
•
Application-dependent recovery
mechanism
– primary and secondary connections
– altering partial or entirety of a path
•
incoming
link 2
backup link
pointer
3
next free slot
pointer
backup link
pointer
4
backup
incoming
link 3
outgoing
link 2
switch
backup
incoming
link 4
Reader-writer flag for handling
timing variability
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outgoing
link 1
backup
outgoing
link 3
backup
outgoing
link 4
controller
line condition monitor
slot buffer
pointer buffer
free slot list
marker checker
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Summary Of Scheduling Techniques
Bounded Delay
Bounded Jitter
Bandwidth
Protection
Advantages
Disadvantages
E-to-E Delay
Bound
Cyclone
Y
Y
Y
Stop-and-Go
Y
Y
Y
Jitter-EDD
Y
Y
Y
WFQ
Y
N
Y
Provides bounded delay and jitter
No additional operations during
data transmission.
No header.
Easy hardware implementation
Clock synchronization
Explicit resource reservations
Provides bounded
delay and jitter
Bounded buffer
requirement
Provides bounded
delay and jitter
Bounded buffer
requirement
Smoothes bursts without
policing
Coupled delay bound
and bandwidth
allocation
To reduce delay jitter,
all packets received a
large delay
Complicate
implementation due to
separate regulator
Costly local delay
bound computation
D
D (or H )
H
Coupled delay bound
and bandwidth
allocation
Expensive round
number computation
 N m
 PH

 N 
2 HT
  H  1S max

Jitter Bound
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Performance Studies
•
•
Data transfer
Connection admission
– long term connections
– single node and multiple nodes
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Type Of Traffic Studied
•
•
Regularly spaced traffic
Random pattern traffic
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Regularly Spaced Traffic (S5-S7)
(S5: 5-10%) 97.33% Loading
(S6: 10-20%) 94.32% Loading
(S7: 5-33%) 95.24% Loading
120
80
60
40
20
97
93
89
85
81
77
73
69
65
61
57
53
49
45
41
37
33
29
25
21
17
13
9
5
0
1
number of slots
100
number of trials
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(S7) 98.1% Loading
trials
26-30 of
(S7)
number
of additionally
used
slots after 15 requests
number of used slots before the first rejection
105
120
95
80
number of additionally used
slots after 15 requests
60
90
number of used slots before the
first rejection
40
85
University Of Maryland
97
93
89
85
81
77
73
69
65
4
5
number of trials number of trials
61
57
53
49
45
41
37
3
33
29
25
2
21
17
13
1
9
0
75
5
20
80
1
number
of slots
slots
number of
100
100
31
Random Pattern (S8)
120
100
80
p(a)
60
d-avg
40
20
0
0
20
40
60
80
100
120
% of available slots requested
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Random Pattern (S9)
100
90
80
70
60
50
40
30
20
10
0
p(a)
d-avg
0
20
40
60
80
100
120
% of available slots requested
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Random Pattern (S10)
120
100
80
p(a)
60
d-avg
40
20
0
0
20
40
60
80
100
120
% of available slots requested
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Random Pattern (S11)
120
100
80
p(a)
60
d-avg
40
20
0
0
20
40
60
80
100
120
% of available slots requested
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Multiple Nodes
•
•
Multiplied probability
End-to-end delay is added
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Summary Of Performance Issues
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•
•
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A couple of millisecond per node connection establishment overhead
Close to 100% loading for identical, regularly spaced traffic
Above 90% loading for regularly spaced traffic
Above 80% loading for arbitrary pattern traffic, requesting 10% of bandwidth
More than 50% of acceptance when links are 80% loaded, requesting 10% of
bandwidth
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Summary
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•
Time-based resource management approach in networking
All aspects of a computer network required to support time-based resource
management
–
–
–
–
–
•
both scheduled and on-demand traffic
end-to-end resource usage scheduling in time
calendar-based data movements
existing applications and communications with non-Cyclone network
fault condition handling
The feasibility of Cyclone technology
– end-to-end delay
– connection establishment overhead
– the probability of connection acceptance
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Advantages
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•
•
•
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Temporal determinacy
Loss free and jitter free end-to-end data delivery with minimal latency, without
sustaining significant delays in connection establishment
Nearly all of the bandwidth available for the actual transmission of data
High loading without having any adverse impact on performance
Well-suited for hardware implementation
Highly scalable
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Limitations
•
Temporal determinacy
– temporal profile of a connection be known ahead
– not current practice in networking
•
•
Handling applications with significant variability
Synchronous system
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Open Issues
•
•
•
•
•
•
•
Alternative designs and policies
Optimization of many system parameters
Design tradeoff and optimization for specific applications
Dynamic monitoring of performance
Support existing internetworking protocols other than TCP/IP
Extensions to point-to-point links and point-to-point connections
Hardware design
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Value Added
•
•
Time-based resource management
Alternate way of managing resources in networking
– without requiring very accurate and highly synchronized clocks
– without consuming significant amount of bandwidth for handling timing variability
•
•
Current applications with stringent timing requirement will perform better
Lead to development of new classes of applications that are possible only
when tight timing guarantee can be given
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Pathfinder
12
4
7
2
S
1
4
2
15
2
12
7
6
15
D
4 15
6
4
marker
S
D
43210
43210
4
2
7
12
15
4
15
6
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3
15
padding
checksum
43
Connection Establishment/Termination
C
2
1
B
A
D
3
5
4
E
6
7
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