1. Slides for Chapter 3: Networking and Internetworking
From Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design
Edition 4, © Pearson Education 2005

2. Figure 3.1 Network performance
Example
Range
Bandwidth
(Mbps)
Latency
(ms)
Wired:
LAN
Ethernet
1-2 kms
1-10
WAN
IP routing
worldwide
MAN
ATM
250 kms
1-150 10
Internetwork
Internet
Wireless:
WPAN
Bluetooth ( ) m
0.5-2
5-20
WLAN
WiFi (IEEE ) km
2-54
WMAN
WiMAX (802.16)
550 km
1.5-20
WWAN
GSM, 3G phone nets
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

3. Figure 3.2 Conceptual layering of protocol software
Message sent
Message received
Layer n
Layer 2
Layer 1
Sender
Communication
Recipient
medium
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

4. Figure 3.3 Encapsulation as it is applied in layered protocols
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

5. Figure 3.4 Protocol layers in the ISO Open Systems Interconnection (OSI) model
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

6. Figure 3.5 OSI protocol summary
Layer
Description
Examples
Application
Protocols that are designed to meet the communication requirements of
specific applications, often defining the interface to a service.
HTTP,
FTP ,
SMTP,
CORBA IIOP
Presentation
Protocols at this level transmit data in a network representation that is
independent of the representations used in individual computers, which may
differ. Encryption is also performed in this layer, if required.
Secure Sockets (
SSL),CORBA Data
Rep.
Session
At this level reliability and adaptation are performed, such as detection of
failures and automatic recovery.
Transport
This is the lowest level at which messages (rather than packets) are handled.
Messages are addressed to communication ports attached to processes,
Protocols in this layer may be connection-oriented or connectionless.
TCP,
UDP
Network
Transfers data packets between computers in a specific network. In a WAN
or an internetwork this involves the generation of a route passing through
routers. In a single LAN no routing is required.
IP,
ATM virtual
circuits
Data link
Responsible for transmission of packets between nodes that are directly
connected by a physical link. In a WAN transmission is between pairs of
routers or between routers and hosts. In a LAN it is between any pair of hosts.
Ethernet MAC,
ATM cell transfer,
PPP
Physical
The circuits and hardware that drive the network. It transmits sequences of
binary data by analogue signalling, using amplitude or frequency modulation
of electrical signals (on cable circuits), light signals (on fibre optic circuits)
or other electromagnetic signals (on radio and microwave circuits).
Ethernet base- band
signalling,
ISDN
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

7. OSI Protocol Summary Layer Description Examples Application
Protocols designed to meet the communication requirements of specific applications, defining the interface to the service
HTTP, FTP, SMTP, IIOP
Presentation
Protocols to transmit data in a network representation that is independent of the representation in individual computers; big/little endian, encryption, compression, EBCDIC to ASCII
TLS security,
Session
Reliability and adaptation are performed. Detection of failure and automatic recovery; checkpointing; tunneling; authentication; permissions; synchronization
SSH, web conferencing
Transport
Communication addresses and ports are attached; connection-oriented or connectionless; congestion and flow control; packet assembly ; ports
TCP, UDP
Network
Host addressing; end-end delivery; packet forwarding; routing
IPV4/IPV6; RIP
Datalink
Transmission of packets from node to node; LAN: between hosts; WAN: between routers; parity error detection and correction: transmission error
Ethernet MAC, PPP
Physical
The circuits and the hardware that drive the network; bytes and bits of data transmission: electrical signals, optical signals, radio and microwave signals; signaling, circuit switching
RS-232C,
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

8. Figure 3.6 Internetwork layers
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

9. Figure 3.7 Routing in a wide area network
Hosts
Links
or local
networks A D E B C 1 2 5 4 3 6
Routers
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

10. Figure 3.8 Routing tables for the network in Figure 3.7
Routings from A
Routings from B
Routings from C To
Link
Cost A B C D E
local 1 3 2 4 5
Routings from D
Routings from E To
Link
Cost A B C D E 3 6
local 1 2 4 5
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

11. Figure 3.9 Pseudo-code for RIP routing algorithm
Send: Each t seconds or when Tl changes, send Tl on each non-faulty outgoing link.
Receive: Whenever a routing table Tr is received on link n:
for all rows Rr in Tr {
if (Rr.link ≠ n) {
Rr.cost = Rr.cost + 1;
Rr.link = n;
if (Rr.destination is not in Tl) add Rr to Tl;
// add new destination to Tl
else for all rows Rl in Tl {
if (Rr.destination = Rl.destination and
(Rr.cost < Rl.cost or Rl.link = n)) Rl = Rr;
// Rr.cost < Rl.cost : remote node has better route
// Rl.link = n : remote node is more authoritative }
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

12. Figure 3.11 Tunnelling for IPv6 migrationB
IPv6
IPv6 encapsulated in IPv4 packets
Encapsulators
IPv4 network
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

13. Figure 3.12 TCP/IP layers Message Layers Application
Messages (UDP) or Streams (TCP)
Application
Transport
Internet
UDP or TCP packets
IP datagrams
Network-specific frames
Message
Layers
Underlying network
Network interface
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

14. Figure 3.13 Encapsulation in a message transmitted via TCP over an Ethernet
Application message
TCP header
IP header
Ethernet header
Ethernet frame
port
TCP IP
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

15. Figure 3.14 The programmer's conceptual view of a TCP/IP Internet
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

16. Figure 3.15 Internet address structure, showing field sizes in bits
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

17. Figure 3.16 Decimal representation of Internet addresses
octet 1
octet 2
octet 3
Range of addresses
Network ID
Host ID to
Class A:
1 to 127
0 to 255
0 to 255
0 to 255
Network ID
Host ID
Class B: to
128 to 191
0 to 255
0 to 255
0 to 255
Network ID
Host ID to
Class C:
192 to 223
0 to 255
0 to 255
1 to 254
Multicast address
Multicast address to
Class D (multicast):
224 to 239
0 to 255
0 to 255
1 to 254 to
Class E (reserved):
240 to 255
0 to 255
0 to 255
1 to 254
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

18. Figure 3.17 IP packet layout
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

19. Figure 3.19 IPv6 header layout
Source address
(128 bits)
Destination address
Version (4 bits)
Traffic class (8 bits)
Flow label (20 bits)
Payload length (16 bits)
Hop limit (8 bits)
Next header (8 bits)
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

20. Figure 3.25 Bluetooth frame structure
bits: 72 18
Access code
Header
copy 1
Header copy 2
copy 3
Data for transmission
bits: 3 1 4 8
Destination
Flow
Ack
Seq
Type
Header checksum
Address within
Piconet
= ACL, SCO,
poll, null
Header
SCO packets (e.g. for voice data) have a 240-bit payload containing 80 bits of data triplicated, filling exactly one timeslot.
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

21. Figure 3.26 ATM protocol layers
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

22. Figure 3.27 ATM cell layout
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005

23. Figure 3.28 Switching virtual paths in an ATM network
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn © Pearson Education 2005