Mainframe: IBM,
Honeywell, CDC
Client/Server: Novell, Banyan, Windows NT 4/2000
Two-tier
Three-tier
Peer-to-Peer (Distributed): NetBEUI, Windows in
Workgroups, Napster, SETI
Bus:
Star:
Ring:
Star-Bus (Hybrid):
Mesh (Full, Partial):
Access
Distribution
Core
Common Network Operating Systems (NOSs)
Microsoft Win9x/ME:
Microsoft NT/2000/XP/.NET:
Novell 3.x:
Novell 4.x:
Novell 5.x:
Novell 6.x:
UNIX:
AppleTalk:
Process/Application: Negotiation
Host-to-Host: Encapsulation
(TCP, UDP, SPX)
Internet: Encapsulation
(IP, IPX)
Network Access: Encapsulation (E’net, Token Ring, FDDI, HDLC, PPP) / Electrical & Optical
Application: Negotiation
Presentation: Negotiation
Session: Negotiation
Transport: Encapsulation
(TCP, UDP, SPX)
Network: Encapsulation
(IP, IPX)
Data Link: Encapsulation
(E’net, Token Ring, FDDI, HDLC, PPP)
Physical: Electrical
or Optical signals
Application Layer:
TCP/IP
Simple Mail Transfer Protocol (SMTP)
BootP/Dynamic Host Configuration Protocol (DHCP)
File Transfer Protocol (FTP)
HyperText Transfer Protocol (HTTP)
Simple Network Management Protocol (SNMP)
Domain Name Service (DNS)
Microsoft
Server Message Block Protocol (SMB)
Kerberos (Authentication Protocol for Win2K)
UNIX/Linux
Network File System (NFS) – also placed at the
Session Layer by some
SAMBA (SMB Emulator)
Network Information System (NIS/NIS+)
Kerberos (Authentication Protocol)
Novell
Novell Core Protocols (NCP)
Apple
AppleTalk Filing Protocol
International
X.400 (International Addressing Standard)
X.500 (International Directory Standard)
LDAP (lightweight Directory Access Protocol)
Presentation Layer:
Character
sets used (ASCII, EBCDIC, Unicode)
File formats (JPEG, MPEG, MIDI, bitstream, text, formatted text)
Compression
Encryption
Session Layer: (Separates application data)
Network File System (NFS)
Structured Query Language (SQL)
Remote Procedure Calls (RPC)
X Window
AppleTalk Session Protocol (ASP)
Digital Network Architecture Session Control
Protocol (DNA SCP)
Transport: (The protocol data unit or PDU is called a
segment at this layer)
Breaks Large Pieces of Higher-level Data into Segments of Size Appropriate to the Network
Flow Control (Negotiate receive buffer sizes, Identify ports to be used, Set up sequence numbers)
Tracking Remote Window
Sending Acknowledgements
Network: (The PDU is called a packet at this layer)
Logical
Addressing
Identify Routes
Determine Costs to Remote Networks
Routers Operate Primarily at the Network Layer with
Increasing levels of Transport Function
(They learn the network layer addresses in the
network and how to reach them. They
make additional decisions based on Transport Layer data)
(Routers do not know the addresses of individual
hosts except to form frames to send to hosts)
Data Link: (The PDU is called a frame at this layer)
Identify
the Higher-level Stack to Receive the Data (TCP/IP, IPX/SPX, DecNet, IBM SNA)
Ensure Hardware Data Addressing (non-logical)
Set Bitstream Format (Canonical vs. non-Canonical)
Switches Operate Primarily at the Data Link Layer
(i.e. They learn the Data Link addresses of attached stations, but know nothing
of the Network Layer Addresses).
End Users Do Not Control Data Link Addressing
Physical (PHY):
Set Transmission Characteristics
Optical Wavelength, Pulse Intensity, Pulse Duration,
Pulse Frequency
Electrical Voltage, Pulse Duration, Pulse Frequency,
Pulse Encoding
Cable Characteristics such as Connectors,
Resistance, Diameter (FO), Maximum/Minimum Lengths
Hubs Operate at the PHY (They reshape pulses only)
Major Networking Protocols:
TCP/IP – Open Standard,
Routable, Protocol of the Internet
IPX/SPX – Proprietary
(Novell), Routable
NetBEUI – Proprietary (IBM/Microsoft),
Non-routable
AppleTalk – Proprietary (Apple),
Routable
Data Link Control (DLC) –
Proprietary (IBM), Non-routable
DECNet – Proprietary
(Digital/Compaq/HP), Routable
Local Area Transport (LAT) –
Proprietary (Digital/Compaq/HP), Non-routable
Systems Network Architecture
(SNA) – Proprietary (IBM), Non-routable
Communication Types:
Connection-oriented –
registered letter – TCP, SPX
Connectionless – postcard –
UDP, IPX
TCP/IP:
Primary Protocol Suite
Internet Protocol (IP):
Logical addressing and routing
Address Resolution Protocol
(ARP): Connect logical IP addresses to “real” hardware addresses on the network
Transmission Control
Protocol (TCP): Packages application data for reliable transport
User Datagram Protocol (UDP):
Packages application data for quick, not-necessarily reliable transport
Large Number of Support
Protocols: ICMP, DNS, DHCP, SMTP, FTP, Telnet, TFTP, RIP
Uses 32-bit (4-byte)
addresses and network masks
Class A – 8-bit (1-byte) network
mask of 1’s with the remainder 0’s; 126 networks of approx. 16,000,000 hosts
Class B – 16-bit (2-byte)
network mask; about 16,000 networks with approximately 65,000 hosts
Class C – 24-bit (3-byte)
network mask; approximately 2,000,000 networks with 254 hosts
IPX/SPX:
Primary Protocol Suite:
Internet Packet eXchange (IPX):
Logical addressing and routing
Sequenced Packet eXchange (SPX):
Session setup and management
Support Protocols: NCP,
NLSP, IPX RIP
Uses 80-bit (10-byte)
address: a 32-bit/4-byte administrator-assigned network number and the
48-bit/6-byte MAC address of the network adapter
Directory Services:
Banyan Vines: Street Talk
Novell: Netware 4.x, Novell
Directory Service (NDS)
UNIX: NIS/NIS+
Microsoft: NTDS (SAM) for
NT, Active Directory (A.D.) for Windows 2000
X.500
Lightweight Directory Access
Protocol (LDAP)
Network Hardware:
Overview:
Local Area Networks (LANs):
Locally owned and managed
Wide Area Networks (WANs): Leased
from a vendor, managed by the vendor, links LAN pieces (the Internet)
Network Access Points
(NAPs): Owned by large telco providers, used by ISPs to exchange traffic,
generically used for all internet exchanges
Components:
NICs and Drivers: NDIS
(Microsoft) and ODI (Novell)
Repeaters and Hubs:
Layer 1, reshape pulses
No knowledge of traffic
Bridges and Switches:
Layer 2
Knowledge of attached
hardware devices (MAC addresses)
Spanning Tree Protocol
Bridging loops and packet
amplification
Bridge Protocol Data Units
Routers (and Brouters):
Layer 3
Knowledge of networks within
the universe
Limited knowledge of local
hardware addresses
Variety of Routing Protocols
(RIP, OSPF, BGP4, IPX RIP, NLSP, AppleTalk RTMP)
Distance Vector Protocols
Link State Protocols
Gateways:
CSU/DSU:
Patch Panels/Wall Jacks:
Ports:
Serial: 9-pin, 25-pin, Data
Terminal Equipment (DTE), Data Circuit Terminating Equipment (DCE), 115 kbps
Parallel: Printers
Universal Serial Bus: v.2 60
- MB/sec, daisy-chainable to 127 devices
FireWire (IEEE 1394): 1394b
- 400 MB/sec, daisy-chainable to 63 devces
Small Computer Systems
Interface (SCSI)
SCSI-1: 25-pin connector,
8-bit bus, DB form factor, 4 Mbps, not daisy-chainable must use SCSI-2 cables
to daisy-chain)
SCSI-2 (“wide”): 50-pin
connector, 8-bit bus, Centronics 50 form factor, 4 Mbps, daisy-chainable
SCSI-3 (“ultra-wide”):
68-pin connector, 16-bit bus, Centronics 68 form factor, 80 Mbps (120?),
daisy-chainable
Media:
Electrical:
Coaxial cable: 50 Ohm, RG-8/RG-11 (10Base5), RG-58
(10Base2), BNC connectors for 10BASE2, screw connectors for 10BASE5
Shielded Twisted Pair (STP): each ground/signal pair encased in a conducting shield, token ring and gigabit E’net Cat7
Unshielded Twisted Pair
(UTP): several categories (“CatX”) for different levels of service
Cat1: telephony, only
Cat2: four pairs, data to 4
Mbps, UTP token ring
Cat3: Four twisted pairs, data
to 10 Mbps, classical star-topology E’net 10BASE-T, beware split cable plants
Cat4: Four twisted pairs,
data to 16 Mbps, later token ring
Cat5: Four twisted pairs,
data to 100 Mbps, 100BASE-TX fast E’net
Cat5e: Improved Cat5 to work
with gigabit E’net
Cat6: Four twisted pairs,
data to 1 gigabit, rigid cable with fixed pair geometry from end to end
Cat7: Four twisted pairs,
shielded, improved gigabit performance
Register Jack 45 (RJ-45): 8-wire connector with form factor similar to a telephone jack (RJ-11)
Register Jack 21 (RJ-11): High-density,
50-pin telco jack, multiplexes 12 lines into one connector
Fiber-Optic:
Multimode (MM): 62.5
micron/125 micron, short haul
Single-mode (SM): 6
micron/125 micron, long haul
Connectors:
BiConic:
ST: Bayonet connector style,
individual fiber
SC: Snap connector style,
individual fiber
MTRJ: Snap style, fiber pair
Sources:
LASER: Longer wavelength systems (infrared), SM cable,
long haul
LED: Shorter wavelength systems (visible) tend to be
LED, MM cable, short haul
Wireless:
The most important protocol
available today is 802.11b
Direct Sequence Spread
Spectrum (Hedy Lamar)
Operates at 11 Mbps under
optimum conditions
As reception degrades
(distance, obstacles) less sophisticated coding is switched in, which reduces
the bit rate.
See http://www.networkcomputing.com/1115/1115ws2.html