1. CCNA 2
Review of Cisco CCNA 1

2. Review will cover… Review the OSI Model Encapsulation
LAN Devices & Technologies
Transport Layer
IP Addressing

3. Open Systems Interconnected Reference Model
Review The OSI Model
Open Systems Interconnected Reference Model

4. Why A Layered Model?
Reduces complexity- by dividing complex operations of internetworking into smaller subsets
Accelerates evolution
Simplifies teaching & learning

5. Application Layer
Application
Provides network services (processes) to applications.
For example, a computer on a LAN can save files to a server using a ________________ supplied by NOSs like Novell.
Network redirectors _________ __________________________________________________.
Presentation
Session
Transport
Network
Data-Link
Physical

6. Presentation Layer
Application
Provides __________________ ________________________.
Code formatting includes __________________________
Basically, the presentation layer is responsible for representing data so that the source and destination can communicate at the application layer.
Presentation
Session
Transport
Network
Data-Link
Physical

7. Session Layer Application
Provides inter-host communication by __________________________ ____________________________
Session uses dialog control and dialog separation to manage the session
Some Session protocols:
NFS (Network File System)
SQL (Structured Query Language)
RPC (Remote Procedure Call )
Presentation
Session
Transport
Network
Data-Link
Physical

8. Transport Layer Application
__________________________________________________ through the use of TCP.
TCP ________________, adding a header with control information for sequencing and acknowledging packets received.
The segment header also includes source and destination ports for upper-layer applications
TCP is connection-oriented and uses __________________________.
UDP is connectionless. UDP __________ __________________________________.
Presentation
Session
Transport
Network
Data-Link
Physical

9. Network Layer Application
Responsible for ________________ _____________________________.
Addressing is done through _______ protocols such as _________, IPX, AppleTalk, and DECnet.
_______________ is done by using ______________ protocols such as ______________________, and BGP.
__________ operate at the Network Layer
Presentation
Session
Transport
Network
Data-Link
Physical

10. Data-Link Layer Broken into two sublayers – ________ _________________
Application
Broken into two sublayers – ________ _________________
Provides access to the media
Handles error notification, network topology issues, and physically addressing the frame.
Media Access Control through either...
Deterministic—
Non-deterministic—
Presentation
Session
Transport
Network
Data-Link
Physical

11. Physical Layer
Provides electrical and functional means for activating and maintaining links between systems.
Ex: ____________________
Includes the medium through which bits flow. Media can be...
Application
Presentation
Session
Transport
Network
Data-Link
Physical

12. Encapsulation Example
Application
You type an message. SMTP takes the data and passes it to the Presentation Layer.
Presentation codes the data as ASCII and adds a header
Session establishes a connection with the destination for the purpose of transporting the data and adds a header
Presentation
Session
Transport
Network
Data-Link
Physical

13. Encapsulation Example
Transport segments the data using TCP and hands it to the Network Layer for addressing also adding a header
Network addresses the packet using IP and adds a header of its own.
Data-Link then encaps. the packet in a frame and addresses it for local delivery (MACs). This layer adds both header and a trailer
The Physical layer sends the bits down the wire.
Application
Presentation
Session
Transport
Network
Data-Link
Physical

14. LAN Devices and Technologies
What does it do?
Connects LAN segments;
Filters traffic based on MAC addresses; and
Separates collision domains based upon MAC addresses.
What layer device?

15. Devices What does it do? What layer device?
Since it is a multi-port bridge, it
However, switches also offer

16. Devices What does it do? What layer device?
Concentrates LAN connections from multiple devices into one location
________________ (a hub is a multi-port repeater)

17. Devices What layer device? What does it do?
Re-encapsulates the packet in the appropriate frame format and _____________ ____________________
Uses ___________ addressing (i.e. IP addresses) to determine the path

18. Media Types

19. Three Most Commonly Used Today in Networking
LAN Technologies
Three Most Commonly Used Today in Networking

20. Ethernet/802.3 100 Mbps Ethernet is also known as ______ Ethernet.
10BASE-5, 10BASE-2, and 10BASE-T Ethernet are considered _______________ Ethernet.
100 Mbps Ethernet is also known as ______ Ethernet.
100BASE-TX, which is __________________, and 100BASE-FX, which is ______________________ based
Gigabit Ethernet standards represent transmission using both fiber and copper media.
______________________________ (IEEE 802.3z)
specifies a 1-Gbps full duplex over optical fiber
The 1000BASE-T standard (IEEE 802.3ab) uses a media of Category 5 or higher UTP.

21. Ethernet/802.3 Ethernet is broadcast topology. What does that mean?
Every devices on the Ethernet segment sees every frame.
__________________________________________________________________________________________________: FFFF.FFFF.FFFF
What is the main network traffic problem caused by Ethernet broadcast topologies?
Ethernet topologies are also shared media
What does this mean?
Collisions are resolved or minimized using what device?

22. CSMA/CD (Carrier Sense Multiple Access with Collision Detection)
How CSMA/CD works:
A node needing to transmit listens for activity on the media. If there is none, it transmits.
The node continues to listen. A collision is detected by a constant elevation in voltage (a bit can only be a 0 or a 1--it cannot be a 2)
The node generates a jam signal to tell all devices to stop transmitting for a random amount of time (back-off algorithm).
When media is clear of any transmissions, the node can attempt to retransmit.

23. Address Resolution Protocol
In broadcast topologies, we need a way to resolve ____________________________ ________________________
ARP is protocol where the sending device sends out a broadcast ARP request which says, “What’s your MAC address?”
If the destination exists on the same LAN segment as the source, then ______________ ____________________________________

24. ARP cont…
If the destination and source are separated by a router, the router will not forward the broadcast (an important function of routers).
Router replies ________________________.

25. Transport Layer
A Quick Review

26. Transport’s Two Protocols
TCP- Transmission Control Protocol
Synchronization of the connection
____________________________
Connection-oriented
_____________________________
“Slow down, you’re overloading my memory buffer!!”
_______________________________________________
Reliability & Error Recovery
_________________: “How much data can I send before getting an acknowledgement?”
Retransmission of lost or unacknowledged segments
Applications:
File Transfer

27. Transport’s Two Protocols cont…
UDP
User Datagram Protocol
_____________________
______________________
Applications:
Routing Protocols
Streaming Audio
Video Conferencing

28. IP Addressing
Subnetting Review

29. Logical Addressing
At the network layer, we use logical, hierarchical addressing.
With Internet Protocol (IP), this address is a ______ addressing scheme divided into ________ octets.
Do you remember the classes 1st octet’s value?
Class A:
Class B:
Class C:
Class D: (multicasting)
Class E: (experimental)

30. Network vs. Host
Class A: 27 = 126 networks; 224 > 16 million hosts N H
Class B : 214 = 16,384 networks; 216 = 65,536 hosts N H
Class C : 221 > 2 million networks; 28 = 256 hosts N H

31. Why Subnet?
Remember: we are usually dealing with a broadcast topology.
Can you imagine what the network traffic overhead would be like on a network with 254 hosts trying to discover each others MAC addresses?
Subnetting allows us to _________________ ___________________________, thereby improving network performance.

32. Borrowing Bits
In order to subnet, we must borrow bits from the ______________ portion on the IP address.
First, we must determine how many subnets we need and how many hosts per subnet.
We do this through the power of 2
For example, I need 8 usable subnets from a Class C:
How many host do we have?

33. Subnet Mask
We determine the subnet mask by adding up the decimal value of the bits we borrowed.
In the previous Class C example, we borrowed 4 bits. Below is the host octet showing the bits we borrowed and their decimal values. 1
We add up the decimal value of these bits and get ___. That’s the last non-zero octet of our subnet mask.
So our subnet mask is ______________________

34. You should be able to:
Calculate the last non-zero octet when given the number of bits borrowed.
Determine the number of bits borrowed given the last non-zero octet.
Determine the amount of bits left over for hosts and the number of host addresses available.

35. CIDR Notation
Classless Interdomain Routing is a method of representing an IP address and its subnet mask with slash followed by a number.
For example: /27
What do you think the 27 tells you?
Also, you know 192 is a _________________________

36. Here’s a shortcut… Magic Number
Given the IP address and the subnet mask, you can determine the first usable subnet quickly.
By knowing the….
Magic Number

37. Magic Number Quick way to determine the first usable subnet.
Generated by subtracting the last non-zero octet of the subnet mask from the number 256
In the previous example: /27
We figured out the subnet mask was:
224 is the ___________________________
The magic number is = 32, so the

38. 202.151.37.0/26 Subnet mask? Bits borrowed? Magic Number?
First useable subnet address?
Second (and last) useable subnet address?

39. 194.53.45.0/29 What kind of address is 194.53.45.26?
Magic number is
Subnets are
So belongs to the
What broadcast address would this host use to communicate with other devices on the same subnet?