Transcript Data Comm For Business, Inc. - Encryption, Multiplexer

Optimizing SCADA Network
Communications:
An Overview of Metropolitan Wide
SCADA Communications Options
by John McCain and Russ Straayer
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The Legacy Approach
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2 and 4 wire phones lines, 1200 bps
VHF and UHF radios
Point-to-Point Microwave
These Were Typically…
– Homogeneous
– Well Understood
– User-Controlled
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Today’s World
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Open Standards
Many Possible Solutions
Simple to Complex
Economical to Expensive
Wired, Wireless, Public, Private
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Wire Line Methods
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Analog Point to Point Modems
Analog Multipoint Modems
DDS
Frame Relay
Point-to-Point and Mesh Networks
• ATM
• T1 and Higher
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Fiber
• SONET or Fiber Ring
• Fiber Ethernet
• New! Fiber Modem
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Wireless
• Wireless Common Carrier Networks
• VHF and UHF Point-to-Point and MultiPoint
• ISM Band License Free
– 900 MHz, 2.4 GHz, 5 GHz
• Point-to-Point Licensed Microwave
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Analog Modems
• Point-to-Point to 19.2 Kbps (Private Wire)
• Multi-Point to 9.6 Kbps
• Hard to purchase, not always available
• The base line for comparison
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DDS
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56/64 Kbps
Point-to-Point or Multi-Point (56)
Digital
May be used with T-1 access line at host
Not always available
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Frame Relay
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Packet Switched Network
Bandwidth available in small increments
Not always available
ECONOMICAL for longer distances
“Automatic” Redundancy
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ATM
• High Speed
• Expensive
• Not usually appropriate for SCADA
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T1 and Higher
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T1, T3, OC-3, etc.
More bandwidth than normally needed
Minimum speed for “useful” Ethernet
May be expensive
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Fiber & SONET
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High cost
High bandwidth
Expertise
Complexity
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Fiber Modem
• Economical addition when adding fiber
for other uses
• Low cost termination for RS-232
equipment
• Lower speed option for fiber
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Fiber Ethernet
• Uses standard Ethernet equipment for
small networks
• Lower cost than SONET
• 10/100 Mbps
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VHF and UHF Radio
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Privately Owned and Maintained
Lower speeds (19.2 Kbps or less)
New frequencies hard to obtain
ISM band equipment often has higher
bandwidth and easier implementation
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Wireless Common-Carrier
Networks
• CDPD pay-per-byte
• Satellite delivery
• Wireless Internet
• Missing Coverage Areas
• Cost
• May be used to fill in “holes”
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ISM Band Radio
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9.6 Kbps to 100 Mbps (claimed:-)
900 Mhz, 2.4 Ghz, 5.8 Ghz
Serial or Ethernet interfaces
Insecure frequencies
Range from several to 100 Miles+
Too Many Unrealistic Vendor Claims!!
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Point-to-Point Microwave
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Licensed, secure
May be expensive
Always Point-to-Point
High Bandwidth
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The Organization Office WAN
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Lay the cost on someone else!
Being forced upon SCADA users
Not Deterministic
Not SCADA-Reliable, No Accountability
• Be Careful Here
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What to Do….
• Start with a Needs Analysis
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Analyze for total life cycle cost
Determine actual bandwidth requirements
Examine in-house expertise
Get to know your vendors….well
What growth requirements are there
Physical and geographic criteria?
• Consider a “MIXED” system!
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Conclusion
• A successful SCADA WAN network is usually a compromise between
reliability, cost, bandwidth, and flexibility. Today, more than ever,
SCADA operators must economize while still providing the necessary
control and data acquisition functions with increased reliability. Most
SCADA networks contain a technology mixture that grew in
complexity over the years. Insure that your analysis allows for even
more growth in the future as well as flexibility and reliability.
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For More Information
• WWW.ScadaCommunications.COM
• WWW.DCBNET.COM
• Our Booth at PowerGen
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Point to Point Example
• Frame Relay
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Point to Multipoint Example
• Frame Relay
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Multiple Redundant Hosts
Frame Relay
Primary Host Site
SR-BPF-04
DigiCHANNEL
AC
Multiple Units
I/O Device
SR DATA MULTIPLEXER
Athena Frame Switch
DCB
SR-BPF-01/DSU
DCB
Host Computer
T-1
RTU
56 kbps
T1 DSU
Multiple Remote RTUs
SR-BPF-04
Frame Relay-1
56 kbps
T-1
SR DATA MULTIPLEXER
DCB
Backup Host Site
DCB
T1 DSU
SR-BPF-01/DSU
SR-BPF-04
DigiCHANNEL
Athena Frame Switch
AC
I/O Device
Multiple Units
Host Computer
Data Comm for Business Inc.
SR-BPF-04
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September 21, 2001
RTU
Scada F/R with Ethernet Access, Remote
Management
LAN
ACCESS SWITCH
Etherpath
DCB
Access Switch
To Management Ports
Primary Host Site
SR-BPF-04
DigiCHANNEL
AC
I/O Device
Multiple Units
SR DATA MULTIPLEXER
Athena Frame Switch
DCB
SR-BPF-01/DSU
DCB
Host Computer
T-1
RTU
56 kbps
T1 DSU
1-250 Remote RTUs
SR-BPF-04
Frame Relay-1
56 kbps
T-1
SR DATA MULTIPLEXER
DCB
SR-BPF-04
DCB
T1 DSU
Multiple Units
DigiCHANNEL
Athena Frame Switch
AC
I/O Device
SR-BPF-04
Host Computer
To Management Ports
ACCESS SWITCH
DCB
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Etherpath
LAN
Access Switch
Backup Host Site
SR-BPF-01/DSU
RTU
SCADA with F/R, Voice, Ethernet, Backup
Links
Primary Host Site
Phone
Ethernet Hub
Athena Access
Phone
10BaseT
SR-BPF-04
DigiCHANNEL
AC
I/O Device
Multiple Units
SR DATA MULTIPLEXER
Athena Frame Switch
DCB
Athena Access w/56K
DCB
Polling Host Computer
SR-BPF-01
RTU
56 kbps
T-1
T1 DSU
Multiple Remote RTUs
SR-BPF-04
Frame Relay-1
T-1
Backup Host Site
56 kbps
DCB
T1 DSU
RTU
SR DATA MULTIPLEXER
DCB
SR-BPF-04
Athena Access w/56K
SR-BPF-01
Multiple Units
DigiCHANNEL
Athena Frame Switch
AC
10BaseT
I/O Device
Phone
Polling Host Computer
SR-BPF-04
Athena Access
Ethernet Hub
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Phone
SCADA Via Ethernet
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SCADA Via Frame Relay
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Scada via Frame Relay with Redundant
Host Site
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Legacy (Conitel) Protocol Via Frame
Relay
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SCADA Via Routed Ethernet
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Scada Via F/R with Modem or Radio
Backup using ASU-BU
BPF-BU
RTU
Async RS232
Sync Frame Relay
BPF-04
Async BU Sharing Unit
Async RS232
Async RS232
SCADA Host
RS-232/V.24-3
FracT1 DSU
ACCESS SWITCH
DigiCHANNEL
AC
DCB
DCB
Host Serial Ports
FracT1
Async RS232
Async RS232
Frame Relay Network
Async RS232
Modem
Sync Frame Relay
Radio
Dial-up Link
Modem
BPF-BU
Dial-up Link
Async RS232
RTU
Sunc Frame Relay
Tower
Modem
Async RS232
RS-232/V.24-14
RTU
RF Link
Modem
Async RS232
Sync Frame Relay
6/21/01 Russ Straayer
Async RS232
Async RS232
RTU
Tower
Radio
BPF-BU
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BPF-BU
BPF Frame Relay Solution
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1 or 4 ports
Async ports 300 bps to 57600 bps
Composite speeds to 128 kbps
Async protocol transparent
Fast data propagation
Easy to configure
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1 and 4 Ports Units
• Multiple polling systems, one line
• 40 DLCI’s per port
• Support multiple or redundant RTU’s
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Multiple Speeds
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Not all systems run the same speed
Different speeds at each end of the line
Mix systems over the same phone lines
Mix polling and non-polling applications
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Fast Composite
• Faster data propagation
• Matches vendor offerings
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Protocol Transparent
• Setup is much more simple
• More general purpose
• More future proof
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Fast Propagation Times
• 50 to 100 ms
• Comparable to modems
• Less than host timeouts
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Easy Configuration
AT YOUR COMMAND >> SM
SHOW MAP
------------------------------PORT DLCI ASSIGNMENTS [Total 1:3, 2:3,
3:3, 4:3]
---- -------------------------------------------------------------1 16 17 18
2 16 17 18
3 16 17 18
4 16 17 18
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Other DCB SCADA Solutions
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EtherPoll
202T Modems
Fast Poll Modems
SCADA Point to Point Multiplexer
SCADA Point to Multipoint Multiplexer
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