1. Slides for Chapter 9:
Name Services
From Coulouris, Dollimore and Kindberg
Distributed Systems:
Concepts and Design
Edition 4, © Pearson Education 2005

2. Figure 9.1
Composed naming domains used to access a resource from a UR
URL
http://www.cdk3.net:8888/WebExamples/earth.html
DNS lookup
Resource ID (IP number, port number, pathname)
55.55.55.55 8888 WebExamples/earth.html
Web server
Network address
file
2:60:8c:2:b0:5a
Instructor’s Guide for Coulouris,
Dollimore and Kindberg Distributed
Socket
Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000

3. Figure 9.2
Iterative navigation
NS2
2
Name
1 NS1 servers
Client
3
NS3
A client iteratively contacts name servers NS1–NS3 in order to resolve a name
Instructor’s Guide for Coulouris,
Dollimore and Kindberg Distributed
Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000

4. Figure 9.3
Non-recursive and recursive server-controlled navigation
NS2 NS2
2 2
4 3
1 1
NS1 NS1
client client
4 3 5
NS3 NS3
Non-recursive Recursive
server-controlled server-controlled
Instructor’s Guide for Coulouris,
A name server NS1 communicates with other name servers on behalf of a client
Dollimore and Kindberg Distributed
Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000

5. Figure 9.4
DNS name servers
Note: Name server names a.root-servers.net
are in italics, and the (root)
corresponding domains are
in parentheses.
uk
Arrows denote name ns1.nic.uk purdue.edu
server entries (uk) yahoo.com
ns.purdue.edu
(purdue.edu)
co.uk
ns0.ja.net
ac.uk
(ac.uk)
* .purdue.edu
ic.ac.uk
qmw.ac.uk
dcs.qmw.ac.uk *.dcs.qmw.ac.uk *.ic.ac.uk
*.qmw.ac.uk
Instructor’s Guide for Coulouris,
Dollimore and Kindberg Distributed
alpha.qmw.ac.uk
(qmw.ac.uk)
dns0.dcs.qmw.ac.uk
(dcs.qmw.ac.uk)
dns0-doc.ic.ac.uk
(ic.ac.uk)
Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000

6. Figure 9.5
DNS resource records
Record type Meaning Main contents
A A computer address IP number
NS An authoritative name server Domain name for server
CNAME The canonical name for an alias Domain name for alias
SOA Marks the start of data for a zone Parameters governing the zone
WKS A well-known service description List of service names and protocols
PTR Domain name pointer (reverse Domain name
lookups)
HINFO Host information Machine architecture and operating
system
MX Mail exchange List of < preference, host> pairs
TXT Text string Arbitrary text
Instructor’s Guide for Coulouris,
Dollimore and Kindberg Distributed
Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000

7. Figure 9.6
DNS zone data records
domain name time to live class type value
1D IN NS dns0
1D IN NS dns1
1D IN NS cancer.ucs.ed.ac.uk
1D IN MX 1 mail1.qmul.ac.uk
1D IN MX 2 mail2.qmul.ac.uk
domain name time to live class type value
www 1D IN CNAME apricot
apricot 1D IN A 138.37.88.248
dcs 1D IN NS dns0.dcs
dns0.dcs Instructor’s Guide for Coulouris, 138.37.88.249
1D IN A
dcs 1D IN NS dns1.dcs
dns1.dcs
Dollimore and Kindberg A
1D IN
Distributed
138.37.94.248
dcs Systems: Concepts and Design Edn. 3
1D IN NS cancer.ucs.ed.ac.uk
© Addison-Wesley Publishers 2000

8. Figure 9.7
GNS directory tree and value tree for user Peter.Smith
DI: 599 (EC)
DI: 543 UK FR DI: 574
DI: 437 AC
DI: 322 QMW
Peter.Smith
mailboxes password
Alpha Beta Gamma
Instructor’s Guide for Coulouris,
Dollimore and Kindberg Distributed
Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000

9. Figure 9.8
Merging trees under a new root
DI: 633 (WORLD)
Well-known directories:
#599 = #633/EC
#642 = #633/NORTH AMERICA EC NORTH AMERICA
DI: 599 DI: 642
UK FR US CANADA
DI: 543 DI: 574 DI: 732 DI: 457
Instructor’s Guide for Coulouris,
Dollimore and Kindberg Distributed
Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000

10. Figure 9.9
Restructuring the directory
DI: 633(WORLD)
Well-known directories:
#599 = #633/EC
#642 = #633/NORTH AMERICA EC NORTH AMERICA
DI: 599 DI: 642
US US CANADA
DI: 543 UK FR DI: 574 DI: 732 DI: 457
#633/EC/US
Instructor’s Guide for Coulouris,
Dollimore and Kindberg Distributed
Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000

11. Figure 9.10
X.500 service architecture
DUA DSA DSA
DUA DSA
DSA
DSA
DUA
DSA
Instructor’s Guide for Coulouris,
Dollimore and Kindberg Distributed
Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000

12. Figure 9.11
Part of the X.500 Directory Information Tree
X.500 Service (root)
... France (country)Great Britain (country)
Greece (country)
...
... BT Plc (organization)
University of Gormenghast (organization)
...
... Computing Service (organizationalUnit)
Department of Computer Science (organizationalUnit)
Engineering Department (organizationalUnit)
...
... Departmental Staff (organizationalUnit)
ely (applicationProcess)
Instructor’s Guide for Coulouris, Research Students (organizationalUnit)
...
Dollimore and Kindberg Distributed
... Alice Flintstone (person)... Pat King (person)James Healey (person) Janet Papworth (person) ...
Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000

13. Figure 9.12
An X.500 DIB Entry
info
Alice Flintstone, Departmental Staff, Department of Computer Science,
University of Gormenghast, GB
commonName uid
Alice.L.Flintstone alf
Alice.Flintstone
Alice Flintstone mail
A. Flintstone
alf@dcs.gormenghast.ac.uk
surname Alice.Flintstone@dcs.gormenghast.ac.uk
Flintstone roomNumber
telephoneNumber Z42
+44 986 33 4604 userClass
Instructor’s Guide for Coulouris,
Research Fellow
Dollimore and Kindberg Distributed
Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000