1 Networking Concepts

Question 1

Explain the purpose of a network.

Answer 1

• shared resource;
• security;
• centralised management.

Question 2

Describe the purpose of all seven layers within the OSI model.

Answer 2

• the Physical layer;
   o electrical;
   o optical;
   o wireless;
• the Data Link layer;
   o LLC sub layer;
   o MAC sub layer;
▪ MAC address;
   o data format;
      ▪ description of an Ethernet frame;
          header (addressing);
          data;
          trailer (CRC-error checking);
• the Network layer;
    o Internet Protocol;
• the Transport layer;
    o transport layer protocols (TCP and UDP);
• the Session layer;
• the Presentation layer;
• the Application layer.

(All People Seem to Need Data Processing)

Question 3

Describe the purpose of all four layers within the TCP/IP Stack

Answer 3

the Network Access layer;
the Internet layer;
the Transport layer;
the Application layer.

Question 4

Explain the purpose of a DNS server.

Answer 4

• name resolution;
• storage of network records;
    o A and AAAA;
    o CNAME;
    o PTR;
    o MX;
    o SOA;
    o SRV.

Question 5

Explain the purpose of a DHCP server.

Answer 5

address scopes, exclusions, reservations;

DHCP Process – DORA.

Question 6

Describe and summarise the difference between a LAN and a WAN.

Answer 6

• the role of routers;

* network address translation (NAT).

Question 7

Describe the key operating principles of the following routing protocols:

Answer 7

• distance vector;
o RIP;
o EIGRP;
• link state;
o OSPF.

Question 8

Describe the configuration and use of:
• IPv4 addresses;
• IPv6 addresses;

Answer 8

IPv4 addresses;
o 32 bits, 4 8-bit groups represented in decimal 0-255;
o host segment;
o network segment;
o netmasks;
o loopback;
o APIPA;
o Classes;
   ▪ A;
   ▪ B;
   ▪ C;
   ▪ D (reserved for multicasting);
   ▪ E (reserved);
o classless (CIDR) notation;

IPv6 addresses;
o 128 bits, 8 x 16-bit groups represented as 4 Hexadecimal values;
o 64 bits used for host address;
o 64 bits used for network address;
o link-local address;
o loopback address;
o address representations.

Question 9

Explain the purpose of configuring the IP address of both DHCP and DNS servers on a
client

Answer 9

• automatic IP address allocation (DHCP);

* name resolution (DNS).

Question 10

Identify standard port numbers for common protocols.

Answer 10

• dhcp;
• dns;
• ftp;
• http;
• https;
• imap;
• pop3;
• RDP;
• smtp;
• ssh;
• telnet.

Question 11

Summarise performance characteristics of Ethernet LANs

Answer 11

• Fast Ethernet;
• Gigabit Ethernet;
• 10Gigabit Ethernet;
• Power over Ethernet (PoE).