Chapter 4: Infrastructure Security

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It is very important for anyone studying network security to be familiar with basic networking concepts and methodology. It is extremely important that you have a working knowledge of the material discussed in this chapter before you take the Security+ exam. We will begin our study of communications and networking with the industry standards and methodologies by which most networks are engineered. Then, we will focus on the physical layouts, components, and protocols used in most networks today. Finally, we will focus our attention on protecting networks from internal and external harm. If you are already familiar with some or all of the topics in this chapter from past experience, consider this chapter an important review of your networking knowledge. It is likely that the exam will drill you with questions from many of the topics discussed in this chapter.

IEEE 802 Specifications

The Institute of Electrical and Electronic Engineers (IEEE) is a technical organization or society that develops standards for local area networks (LANs) and wide area networks (WANs). The IEEE 802 project standards were developed in the 1970s as a set of specifications or rules that manufacturers and users can use as a sort of road map for understanding and developing networks and network related devices. The IEEE specifications are associated with certain networking layers of the OSI (Open Systems Interconnection) networking model, which will be discussed shortly in this chapter.

Project 802 was developed to address standards for network interface cards, network cables, and wide area networks. Many additions have been made to the IEEE 802 standards as technology has progressed.

The original 12 categories of the 802 specifications and their associations are as follows:

• 802.1: Internetworking.

• 802.2: Associated with the Logical Link Control (LLC) sublayer of the OSI networking model.

• 802.3: Carrier-Sense Multiple Access with Collision Detection (CSMA/CD) local area networks (Ethernet).

• 802.4: Token Bus LAN.

• 802.5: Token Ring LAN.

• 802.6: Metropolitan Area Network (MAN).

• 802.7: Broadband Technical Advisory Group.

• 802.8: Fiber Optic Technical Advisory Group

• 802.9: Integrated Voice and Data Networks.

• 802.10: Network Security Technical Advisory Group. Key management.

• 802.11: Wireless Networking.

• 802.11a: Applies to 5 GHz Wireless Technology.

• 802.11b: Applies to 2.4 GHz Wireless Technology

• 802.12: Demand Priority Access Lan100Base VG-AnyLAN.

Later in this chapter, we will discuss topologies such as bus, star, and ring. It is important to remember that the 802.3 Ethernet standards apply to bus and star networks that utilize CSMA/CD (Carrier-Sense Multiple Access with Collision Detection) access methods, while Token Ring topologies utilize token-passing methods to place a data signal on a wire.

The IEEE 802 standards apply mostly to the physical aspects of networking components. For example, they have to do with how a network interface card (NIC) is connected to a network and the particular types of media transmission methods used to carry a signal down a physical wire.

Just about every networking component manufactured today is designed to meet one of the earlier mentioned IEEE standards. If you purchase a hub, cable/DSL router, NIC, or wireless network component, take a look at the specifications on the packaging or in the advertisement. You will see that the product was manufactured to meet one of the standards set forth by the IEEE. If you are interested in learning more about the IEEE and its standards, you can visit the IEEE at http://standards.ieee.org/.

It is not likely that the Security+ exam will focus on the IEEE 802 standards. However, you should understand their underlying concepts and how they relate to the Open Systems Interconnection (OSI) model discussed next.

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