© 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 1 Version 4.0 OSI Data Link Layer Network Fundamentals – Chapter 7

2 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public OSI Reference Model Layer 2

3 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public What will we learn from chapter 7?  Their role in data transmission  Prepare data for transmission on network media  Media access control methods  Common logical network topologies  Encapsulating packets into frames  Layer 2 frame structure - generic fields  Frame header and trailer fields: addressing QoS Type of protocol Frame Check Sequence

4 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Data Link Layer – Accessing the Media

5 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Data Link Layer – Accessing the Media Why Data Link layer protocols required to control media access

6 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Data Link Layer – Accessing the Media

7 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Data Link Layer – Accessing the Media

8 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Data Link Layer – Accessing the Media

9 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Media Access Control Techniques Controlling access to the media

10 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Media Access Control Techniques Two media access control methods for shared media and their basic characteristics

11 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Media Access Control Techniques Full Duplex and Half Duplex as it relates to Media Access Control for non- shared media

12 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Media Access Control Techniques

13 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Media Access Control Techniques

14 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Media Access Control Techniques

15 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Media Access Control Techniques

16 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Media Access Control Techniques

17 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Media Access Control Addressing and Framing Data

18 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Media Access Control Addressing and Framing Data

19 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Media Access Control Addressing and Framing Data The role of addressing in the Data Link layer - cases where addresses are needed – or not needed

20 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Media Access Control Addressing and Framing Data

21 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public What did I Learn from chapter 7?  Their role in data transmission  They prepare data for transmission on network media  Media access control methods  Common logical network topologies  Encapsulating packets into frames  Layer 2 frame structure - generic fields  Frame header and trailer fields: addressing QoS Type of protocol Frame Check Sequence

22 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Data Link Layer Next OSI Physical Layer