1. Curs 6: Nivelul retea
Razvan Zota
10 Nov 2016

2. Chapter Outline 6.0 Introducere 6.1 Protocoale de nivel retea
6.2 Rutarea
6.3 Ruterul
Chapter Outline

3. Nivelul retea in comunicatii

4. Nivelul retea End to End Transport processes Addressing end devices
Encapsulation
Routing
De-encapsulating
The Network Layer

5. Protocoale la nivelul retea
Network Layer Protocols

6. Caracteristici ale protocolului IP

7. Incapsularea IP
Encapsulating IP

8. Incapsularea IP (cont.)
Encapsulating IP

9. Caracteristici IP
Characteristics of IP

10. IP – Connectionless (“fara conexiune”)

11. IP – Connectionless (cont.)

12. IP – Best Effort Delivery

13. IP – Independenta fata de mediul de comunicatie
IP Media Independent
Activity – IP Characteristics

14. Pachetul IPv4
6.1.3 IPv4 Packet

15. Header-ul unui pachet IPv4
Version = 0100
DS = Packet Priority
TTL = Limits life of Packet
Protocol = Upper layer protocol such as TCP
Source IP Address = source of packet
Destination IP Address = destination of packet
IPv4 Packet Header
Video Demonstration - Sample IPv4 Headers in Wireshark
Activity – IPv4 Header Fields

16. Pachetul IPv6
6.1.4 IPv6 Packet

17. Limitari IPv4 IP address depletion Internet routing table expansion
Lack of end-to-end connectivity
Limitations of IPv4

18. Introducere in IPv6 vs. Increased address space
Improved packet handling
Eliminates the need for NAT
4 billion IPv4 addresses
4,000,000,000
340 undecillion IPv6 addresses
340,000,000,000,000,000,000,00 0,000,000,000,000,000
vs.
Introducing IPv6

19. Incapsularea IPv6 IPv6 has a simplified header
Encapsulation IPv6

20. Incapsularea IPv6 (cont.)
IPv6 has a simplified header
Encapsulation IPv6

21. Incapsularea IPv6 (cont.)
Encapsulation IPv6

22. Header-ul unui pachet IPv6
Version = 0110
Traffic Class = Priority
Flow Label = same flow will receive same handling
Payload Length = same as total length
Next Header = Layer 4 Protocol
Hop Limit = Replaces TTL field
IPv6 Packet Header
Video Demonstration - Sample IPv6 Headers and Wireshark
Activity - IPv6 Header Fields

23. Rutarea Upon completion of this section, you should be able to:
Explain how a host device uses routing tables to direct packets to itself, a local destination, or a default gateway.
Compare a host routing table to a routing table in a router.
6.2 Routing

24. Cum ruteaza un host
6.2.1 How a Host Routes

25. Decizii de redirectionare a traficului
Itself
Local Host
Remote Host
Host Forwarding Decision

26. Default Gateway (poarta implicita)
Routes traffic to other networks
Has a local IP address in the same address range as other hosts on the network
Can take data in and forward data out
Default Gateway

27. Utilizarea unui Default Gateway
Using the Default Gateway

28. Tabela de rutarea a unui host
Host Routing Tables

29. Tabele de rutare ale ruterului
6.2.2 Router Routing Tables

30. Decizii de directionare a pachetelor
Router Packet Forwarding Decision

31. Tabela de rutare IPv4 6.2.2.2 IPv4 Router Routing Table
Video Demonstration – Introducing the IPv4 Routing Table

32. Intrari in tabela de rutare direct conectate
Directly Connected Routing Table Entries
Route source – Identifies how the network was learned by the router.
Destination network – Identifies the destination network and how it was learned.
Outgoing interface – Identifies the exit interface to use to forward a packet toward the final destination.

33. Intrari remote in tabela de rutare
Remote Network Routing Table Entries

34. Adresa Next-Hop 6.2.2.6 Next-Hop Address
Video Demonstration – Explaining the IPv4 Routing Table
Activity – Identify Elements of a Router Routing Table Entry

35. Rutere Upon completion of this section, you should be able to:
Describe the common components and interfaces of a router.
Describe the boot-up process of a Cisco IOS router.
6.3 Routers

36. Anatomia unui ruter
6.3.1 Anatomy of a Router

37. Un ruter este un computer
Routers require:
Central processing units (CPUs)
Operating systems (OSs)
Memory consisting of:
Random-access memory (RAM)
Read-only memory (ROM)
Nonvolatile random-access memory (NVRAM)
Flash
The Cisco Internetwork Operating System (IOS) is the system software used for most Cisco devices regardless of the size and type of the device. 

38. Memoria unui ruter RAM uses the following applications and processes:
IOS and running-config
Routing table
ARP cache
Packet buffering
ROM stores the following:
Bootup information that provides the startup instructions
Power-on self-test (POST) that tests all the hardware components
Limited IOS to provide a backup version of the IOS.
Router Memory

39. Interiorul unui ruter
Inside of a Router

40. Conectarea la un ruter Double-wide eHWIC slots eHWIC 0 AUX port LAN
interfaces
Connect to a Router
Console RJ45
USB
Ports
Two 4 GB flash card slots
Console
USB Type B

41. Interfete LAN si WAN 6.3.1.6 LAN and WAN Interfaces
Activity – Identify Router Components
PT – Exploring Internetworking Devices

42. Procesul de bootare a unui router
6.3.2 Router Boot-up

43. Fisiere utilizate in timpul bootarii
Bootset Files

44. Procesul de “Bootup” 6.3.2.2 Router Bootup Process
Video Demonstration – Router Bootup Process

45. Show version output
Show version output

46. Show version output (cont.)
Video Demonstration – The show version command
Activity – The Router Boot Process
Lab – Exploring Router Physical Characteristics