Chpt. 3 Networking Flashcards
OSI Model Layers?
All • People • Seem • To • Need Data • Processing.
Layer 1. Physical Layer ( Cables, Jacks, Patch Panels, Punch Blocks, Hubs).
Layer 2.
Data Link Layer (How transfer is accomplished) Nic Cards, Bridges).
Layer 3. Network Layer (Routing/Switching to diff networks) LAN/Wan IP Address.
Layer 4. Transfer Layer (Error Free Trans between hosts addressing.
Layer 5. Session Layer (Establish, Synch, Terminates, session between network hosts.
Layer 6. Presentation Layer (Translates data format from sender to rec.) File encryption.
Layer 7. Application Layer (Messages) (FTP, SMTP).
Telco Multiplexing DSOs
Analog Voice Freq
Signal: Bit-Rate: Voice Ch. DSO. 64kbps. 1 Ch DS1. 1.544Mbps. 24 Ch DS2. 6.3Mbps. 96 Ch DS3. 44.7 Mbps. 673 Ch DS4. 274.1 Mbps. 4032 Ch
RS-232
Summary
Data Format - 5 to 8 bit serial.
Transfer Type - Asynchronous
Error Handling - Optional Parity Bit
Connector - 25 Pin Female (DCE)
- 25 Pin Male (DTE)
Length - 20 Meters
Speed - 20 Kbps
RS-232 connection between 2 DTE devices very difficult (Must use Null Modem).
RS - 232 (Specs)
Tx Signal Voltage: -------------------- Binary 0 = +5 to +15 VDC 0 =On, 1 = Off Binary 1 = -5 to -15 VDC
Binary 0 = +3 to + 13 VDC
Binary 1 = -3 to -13 VDC
RS-232
SERIAL
Interface between (DTE) and (DCE) equip.
Used between computers and other peripherals.
Send data 1 bit at a time on 1 line.
Good for long distances.
Good over telephone lines, converted to data by Modem.
RS-232
Parallel
Interface between (DTE) Data Termination Equip. and (DCE) Data Communication Equip.
For test equip. Computers and printers.
Requires as many lines as bits in a word.
Ex. 8 bit word = 8 Lines.
Good for short distance.
ATM
Asynchronous Transfer Mode
Put Diff. Protocols and Traffic types into common format over Sonet.
Strong in Metro Area Networks.
For higher speed line interfaces.
Traffic Mgmt capabilities.
Terminate traffic, VoIP, DSL and Frame Relay.
Dynamic Packet Transport
Alternative to SONET Ring Topology
Cisco Protocol alternative to Sonet.
More efficient transport of data in ring topology.
Can run over dark fiber, Sonet, WDM
Can re-use Bandwidth that would’ve been lost (Sonet can’t)
Bidirectional rings.
Point - Point (Topology)
Ultra High Speed/Long Haul Network
Ultra high speed (10 to 40Gbps)
- Reliable
- Long Haul Networks (400 km)
- Protection (Redundancy).
Fiber Chann.
Predominant data link technology in Storage Area Networks (SAN).
100, 200, 400 Mbps
Replaces (SCSI) Cheaper
Better distance than SCSI
Each node is optical repeater.
Network Mgmt Tool?
Comprehensive Network Tool that controls provisioning, performance monitoring, Fault identification, isolation and remedial action.
Ex. (SNMP).
Sonet Multiplexing
(Hierarchy) OCs - Optical Carrier.
Optical Sonet. Bit
Carrier: Signal: Rate:
——– ——– ——-
OC-1 STS-1. 51.8Mbps
OC-3. STS-3. 155.5Mbps
OC-12. STS-12. 622Mbps
OC-48. STS-48. 2.5 Gbps
OC-192. STS-192. 10 Gbps
OC-768. STS 768. 40 Gbps
SAN
Storage Area Network
- Mass Data Storage
- Centrally Managed
- Composed of Servers, Storage devices, network devices.
- Separate Network from LAN
- Relieves bottlenecks in LAN
- Data monitoring, transaction processing, backup/restoration.
Sonet?
Foundations for MANs
Transport Layer for TDM and Overlay network
Expensive
Inefficient voice and Multiplexing hierarchy
Capacity Limitations
Agnostic Protocol - Transports all traffic types
Fiber Maintenance?
Fiber Loss- .25db/km (Attenuation)
Fiber Aging- 2db over life span
