Figure 5-1 Encapsulation
L1 Physical
L3 Network
L5 Session
L7 Applications
L2 Data Link
L4 Transport
L6 Presentation
Source Destination
Data
DataData
Data
Data Stream
Network Header
Network Header
Data
Data Stream
Data Stream
101010001011010101001010100010111110
Frame Header
Frame Trailer
L1 Physical
L3 Network
L5 Session
L7 Applications
L2 Data Link
L4 Transport
L6 Presentation
L = Layer - as L1 = layer 1
Figure 5-2 Data Encapsulation Process
Data
DataData
Data
Email Data Stream
Network Header
Network Header
Data
1010100010111101010101001010100010111110
Frame Header
Frame Trailer
Data
Segment
Packet
Frame
Bits
Email being Composed
Layer 4
Layer 3
Layer 2
Layer 1
Layer 5
Figure 5-3 OSI and TCP/IP models compared
Layer 6 Presentation
Layer 3 Network
Layer 1 Physical
Layer 2 Data Link
Layer 4 Transport
Layer 5 Session
Layer 7 Application
Link
Network
Transport
Application
OSI Model TCP/IP Model
Figure 5-4 An example of a peer-to-peer network
Figure 5-5 An example of a client/cerver network
Server
Client
Figure 6 - Star Topology
Workstation
Server Controller
Figure 5-7 A Bus Topology
Server
Printer
workstation
Computer
Figure 8- Ring Topology
Workstation
Server
Figure 5-9 A CSMA/CD collision
A
B
A
B
A
B
A
B
Clear to
send
Clear to
send
collision
Sending
Sending
Wait random
time
1 2 3 4
Figure 5-10 Collision Domain
Collision Domain
1
Collision Domain
2
or
or Router
Switch
Bridge
Figure 5-11 Modular Jack and Active Hub
RJ45Active Hub
Figure 5-12 A network segment built on a 10 Mbps hub
2 Mbps
10 Mbps2 Mbps
2 Mbps
2 Mbps 2 Mbps
Figure 5-13 Bridging Two Network Segments
A
D
CB
E F
01-3A-2D-6C-0C-2A 01-20-2D-7C-DC-43
01-A2-1D-75-B1-12 01-0B-0D-7C-1F-3D 00-20-6D-7C-01-BC
Segment 1
Segment 2
01-20-0D-7C-01-9A
Bridge
Figure 5-14 An Example of a Switched Ethernet Configuration
EDC
A
B
Server
Ethernet Switch
Workstation
100 Mbps100 Mbps
100 Mbps
100 Mbps
100 Mbps
100 Mbps
Figure 5-15 A VLAN environment
D
Internet or WAN
Accounting
Marketing
Engineering
Server Farm
Figure 5-16 Point-to-Point and Multipoint (daisy-chained)
LAN
CSU/DSU
CSU/DSU
CSU/DSU
CSU/DSU
CSU/DSU
CSU/DSU
LAN
LAN
Paris
Rome
New York
Chicago
LAN
LANCSU/DSU
CSU/DSU
CSU/DSU
CSU/DSU
LAN
LAN
Paris
Rome
New York
Chicago
LAN
Point-to-Point
Multipoint
Figure 5-17 X.25 Pack Switched Network
1
2
3
4
5
6
7
8
9
A4th1-2-3-4-6-5-7-8-9 (longest path)A
D3rd1-2-6-5-6-8-9D
C1st1-3-5-8-9 (shortest path)C
B2nd1-2-4-5-8-9B
Re-Ordered and delivered to computer
“Z”
Packet Arrives at “9”Path Taken
Packets: A, B, C, and D Leave Computer “Y”
via“1”
Computer “Y”
Computer “Z”
Figure 5-18 Statistical Pack switching
Virtual Circuit
B
A
C
A A
AA
AAA
C C C CC
CCB B B B B BBBPacket
Switch
Data Flow
Time Division Multiplexing
Figure 5-19 Combining different services onto a single access channel
Multiplexed cell stream
B
A
C
A A
AA
AAA
C C C CC
CCB B B B B BBBATM
Multiplexer
Data Flow
Voice
Video
Data
Figure 5-22 PVCs in a Frame Relay network
LAPD
SP
LAPD
LAPD
LAPD
LAPDLAPD
LAPD
LAPD
SP
SP
SP
SP
SP
SP = Switch Point
PVC =
DTE or FRAD =
Figure 5-21 Frame Relay frame format (LAPD)
Figure 5-22 Frame Relay bandwidth-on-demand
Collision Domain
Figure 5-12 A Combination of interconnections
Figure 5-13 Three Tiered Network Hierarchy
Figure 5-17Data Service Components
Figure 5-17 DDS Components
DTE DTECSU/DSU CSU/DSUDDS Hub DDS Hub
Physical interfaceV.35
Data Access Lines
Data Access Lines
Physical interfaceV.35
Long-distance digital channel
Figure 5-18 Pack switching
PS
PS
PS
PSPS
PS
PSPS
PS
Terminal
SDLC Host
X.25 Host
RJE Station
Asynch Terminal
Terminal
PS = Packet Switch
Figure 5-1 The OSI model versus the TCP stack
Figure 5-2 An example of a shared-medium LAN
Figure 5-3 An example of Gigabit Ethernet
Figure 5-4 Token passing
Figure 5-5 CSMA/CD
Figure 5-6 Collision Domains
Figure 5-7 RJ45 modular jack and Active Hub
Figure 5-8 shows a network that uses a combination of interconnection
Figure 5-9 Bridging two network segments
Figure 5-10 An example of a switched Ethernet configuration
Figure 5-11 An Ethernet switch
Figure 5-12 A VLAN
Figure 5-13 A three layer network hierarchy
Figure 5-14 Data service components
Figure 5-15 Point to Point leased line and multipoint (daisy chained)
Figure 5-16 DDS components
Figure 5-17 Packet switching
Figure 5-18 Statistical Packet Switching
Figure 5-19 An X.25 packet-switched network
Figure 5-20 Frame Relay frame format (LAP D)
Figure 5-21 PVCs in a Frame Relay network
Figure 5-22 Frame Relay bandwidth-an-demand
Figure 5-23 Combining different services onto a single access channel