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Basics of Communications
Presented By Patrick BolwahnnApril 14, 2005
Today…
• Session Objectives– Learning and Understanding the Basics of Reader
Communication
• Innovation – Terminology– Infrastructure Considerations– Equipment and Devices
• Results– The ability to understand and deploy a well
designed reader network.
WT Background:
• Installed January 1998
• Wired February 1998
• Recarded Fall of 1998
• Services Offered– Copy, Laundry, Vending, Bookstore– Point of Sale, Activity Validation– 120 Locations
WT Background:
• FY 2003-2004– 9000 Active Cardholders– $1.5 Million in Deposits
• Meal Plans – 300k• Book Loans – 350k• Flexible Spending – 850K
– 220 On-Campus Locations and 35 Off-Campus Locations
– Door Access
Terminology:
• Network Processor - Transaction Approval
• Application Processor - Long Term Storage, DB
• Reader Networks – Communications Devices, Wiring and Readers
• Locations - Location Number a Reader is Assigned
• Loop - Physical Wire
• Addresses - numbers 0-15 assigned to reader
Terminology:
• Modems – communication device (RS232)
• Converters – Converts from one protocol to another.
• IP Communications – Communicating over a Data Network
• RS232 • RS485
Terminology :
• Do you have to be a wiring expert?
•NoJust need to know enough to make good decisions
Installation Considerations:
• AP/NP Location• Number & Size of Buildings• Number Readers in each building• Cable topology – fiber, copper• Network Strategy and Support
– Data Network– Separate Reader Network / VLAN
• Power connections• Shelf/rack space
WTAMU Communications:
• Remote Line Driver loops
• IPC loops– 1 IPC Loops
• 25 Active Loops– 24 Remotes Loop– 2 RF Loops
• 265 Locations
Reader Networks:
• Consists of – Network Processor– Communications Devices– Cabling– Readers
• Cabling and Communication Devices make up the three basic reader loops– Local– Remote– IP Network
Network Processor:
• Network Processors communicates with each reader on the network and processes their transactions.
• NP’s Communicationis handled through– CP16 Panels – Mux Panel– LAN Cards
Local Loops:
• Local loops are generally within the same building as the NP. Local loops can be accomplished two ways.– Use CP8 boards which have some RS-485 converters
built in.– CP16 boards do not have converters– NP cable to RS 485 converter
NP485
Reader
Reader
Remote loops:
• A Remote Loop is any loop that services a remote building(s) or remote campuses. This can be accomplished through many combinations of devices.– Devices Types
• Terminal Servers(TS) via a Data Network or Internet• Line Drivers• RS 485 converters.• IP Converters• IP Readers
Communications Protocols:
• Protocols are like different languages. Some protocols the BTSUE system uses to communicate are:– RS 485
• Allows multiple units to communicate over the same wire. ( 5 pin)
– RS 232• Basic data communication used in PC and device
communication, 1 – 1 ( 3 pin)
– TCP/IP • Standard Networking protocol which Terminal servers, IP
Converters, & IP readers utilize on a data network.
Standard Communications:
• Line Drivers– Short haul modems = less than 2 miles– Long distance modems = more than 2 miles– Types of medium
• Fiber• Copper
– Uses Standard RS 232 protocol (3 pin)
Standard Communications:
• Special devices– Multiplexer– Loop Splitters
Standard Communications:
• RS 485 Converters– Design to convert RS 232 to 485 protocol– Has 1x10 jack to
connect local readercable network
Standard Communications:
NP Line Driver Line Driver
485 Reader
Building A
Line Driver
Line DriverLoop
Spliter Building B
Line Driver
Building C
Line Driver
Computer Center
IP Communications:
• Terminal Servers – Designed to Convert RS232 to TCP/IP and
back again.
• IP Converters– Design to convert TCP/IP to RS 485
protocol
• IP enabled Readers VR/MDB2
IP Communications:
Data Network
NP
Terminal Server
RS 485
Reader
Terminal Server
First IP Communications devices were terminal servers
IP Communications:
• IP Converters– Design to convert TCP/IP to RS 485
protocol
IP Communications:
Data Network
NP
IP Converter
RS 485Reader
IPReader
Other Communication Methods:
• Radio Frequency– Blackbox RF-115 modem– 900 Mhz RS232 protocol– Range up to 20 miles
with repeaters
Wiring:
• Supported wiring– Belden 8723
• 2 pair with shield• Use T568b wall plate with screw lugs
or DB 15
– Cat 5 10base-T (most common installation)• Twisted Pair Network Cabling• Use T568b RJ45 standard network jack
Pros for communication types:Local LoopsLower cost – no LD or TS.
-Fast response times.
-Independent wiring – not attached to net.
Line Driver-Fast Response times.
-Independent wiring - not attached to data network.
-Slightly Cheaper than TS.
-Supported by Blackboard
-Simple - No Configuration neededAlways up!
-Works with Copper and Fiber lines
-Easy to troubleshoot
IP- easiest/quickest to install, or move
-Easy to diagnose communication problems???
-Comes back on-line fairly quickly, when the network is out
-Could be used over the Internet to connect remote campuses
Cons for communication types:
Local Loops-Difficult to move server.
Line Driver-Difficult to move server.
-Copper needs optical isolation
- Cost of running wiring if not available
IP-Network Outage
-Denial of Service
-Firewall and VLAN’s can block communication if not configured right.
-Depends highly on relation-ship with IT
Security Issues with IPC:
• IPC’s Communicate with the NP with 128bit Blowfish encryption.
• No problems so far with denial of service attacks.
• Downstream communication between IPC and Reader is still vulnerable.
• Having the IPC on a VLAN and behind a firewall greatly increases security.
Recap:
• Installation Considerations– AP/NP Location– Number & Size of Buildings– Number Readers in each building– Cable topology – fiber, copper– Network Strategy and Support
• Data Network• Separate Reader Network / VLAN
– Power connections– Shelf/rack space
• Links– Behind the Blackboard
• System Implementation Guidehttp://www.blackboard.com/docs//h931431.pdf
• Follow up Contact [email protected]
• If you remember one thing…There are many options for deploying your reader network
