Study Up: A look at standards and practices from a CompTIA Network+ perspective
In previous months, we looked at all of the domains on the new version of the popular CompTIA Network+ certification exam (N10-006) except for the final one: Industry Standards, Practices, and Network Theory. This month we will look at that last domain, weighted at 16 percent of the total exam, and the topics that comprise it.
There are 10 subdomains under the standards and practices (and theory) label and they bounce around in terms of subject matter. To illustrate this, the table below lists them in the order in which they appear in the CompTIA exam objectives:
|5.1||Analyze a scenario and determine the corresponding OSI layer|
|5.2||Explain the basics of network theory and concepts|
|5.3||Given a scenario, deploy the appropriate wireless standard|
|5.4||Given a scenario, deploy the appropriate wired connectivity standard|
|5.5||Given a scenario, implement the appropriate policies or procedures|
|5.6||Summarize safety practices|
|5.7||Given a scenario, install and configure equipment in the appropriate location using best practices|
|5.8||Explain the basics of change management procedures|
|5.9||Compare and contrast the following ports and protocols|
|5.10||Given a scenario, configure and apply the appropriate ports and protocols|
As with all the domains and topics on this exam, a combination of common sense and a little bit of knowledge and experience (9 to 12 months of work experience in IT networking) is the best tool for helping you pick the right answer on multiple-choice exam questions.
What You Need to Know
The following discussion is intended to represent a study guide for this domain. It does not include every topic (space will not allow for that), but it covers most of the main topics. Most of the bullets and tables are very straightforward but if you don’t understand any of the subjects, then you would be well-advised to research them further.
● As data is passed up or down through the OSI model structure, headers are added (going down) or removed (going up) at each layer: a process called encapsulation (when added) or decapsulation (when removed).
Table 1: Summary of the OSI Model
|Application (Layer 7)||Provides access to the network for applications and certain end-user functions. Displays incoming information and prepares outgoing information for network access.|
|Presentation (Layer 6)||Converts data from the application layer into a format that can be sent over the network. Converts data from the session layer into a format that the application layer can understand. Encrypts and decrypts data. Provides compression and decompression functionality.|
|Session (Layer 5)||Synchronizes the data exchange between applications on separate devices. Handles error detection and notification to the peer layer on the other device.|
|Transport (Layer 4)||Establishes, maintains, and breaks connections between two devices. Determines the ordering and priorities of data. Performs error checking and verification and handles retransmissions if necessary.|
|Network (Layer 3)||Provides mechanisms for the routing of data between devices across single or multiple network segments. Handles the discovery of destination systems and addressing.|
|Data link (Layer 2)||Has two distinct sublayers: link layer control (LLC) and media access control (MAC). Performs error detection and handling for the transmitted signals. Defines the method by which the medium is accessed. Defines hardware addressing through the MAC sublayer.|
|Physical (Layer 1)||Defines the network’s physical structure. Defines voltage/signal rates and the physical connection methods. Defines the physical topology.|
● Connection-oriented protocols such as TCP (Transmission Control Protocol) can accommodate lost or dropped packets by asking the sending device to retransmit them. They can do this because they wait for all the packets in a message to be received before considering the transmission complete.
● On the sending end, connection-oriented protocols also assume that a lack of acknowledgment is sufficient reason to retransmit.
Table 2: Port Assignments for Commonly Used Protocols
|NetBIOS||137 – 139|
● In addition to providing best-effort delivery, IP also performs fragmentation and reassembly tasks for network transmissions.
● Fragmentation is necessary because the maximum transmission unit (MTU) size is limited in IP. In other words, network transmissions that are too big to traverse the network in a single packet must be broken into smaller chunks and reassembled at the other end.
Table 3: TCP/IP Suite Selected Summary
|IP||Internet Protocol||A connectionless protocol used to move data around a network.|
|TCP||Transmission Control Protocol||A connection-oriented protocol that offers flow control, sequencing, and retransmission of dropped packets.|
|UDP||User Datagram Protocol||A connectionless alternative to TCP used for applications that do not require the functions offered by TCP.|
|FTP||File Transfer Protocol||A protocol for uploading and downloading files to and from a remote host. Also accommodates basic file-management tasks.|
|SFTP||Secure File Transfer Protocol||A protocol for securely uploading and downloading files to and from a remote host. Based on SSH security.|
|TFTP||Trivial File Transfer Protocol||A file transfer protocol that does not have the security or error checking of FTP. TFTP uses UDP as a transport protocol and therefore is connectionless.|
|SMTP||Simple Mail Transfer Protocol||A mechanism for transporting email across networks.|
|HTTP||Hypertext Transfer Protocol||A protocol for retrieving files from a web server.|
|HTTPS||Hypertext Transfer Protocol Secure||A secure protocol for retrieving files from a web server.|
|POP3/IMAP4||Post Office Protocol version 3/ Internet Message Access Protocol version 4||Used to retrieve email from the server on which it is stored. Can only be used to retrieve mail. IMAP and POP cannot be used to send mail.|
|Telnet||Telnet||Allows sessions to be opened on a remote host.|
|SSH||Secure Shell||Allows secure sessions to be opened on a remote host.|
|ICMP||Internet Control Message Protocol||Used on IP-based networks for error reporting, flow control, and route testing.|
|ARP||Address Resolution Protocol||Resolves IP addresses to MAC addresses to enable communication between devices.|
|RARP||Reverse Address Resolution Protocol||Resolves MAC addresses to IP addresses.|
|NTP||Network Time Protocol||Used to communicate time synchronization information between devices.|
|NNTP||Network News Transfer Protocol||Facilitates the access and downloading of messages from newsgroup servers.|
|SCP||Secure Copy Protocol||Allows files to be copied securely between two systems. Uses Secure Shell (SSH) technology to provide encryption services.|
|LDAP||Lightweight Directory Access Protocol||A protocol used to access and query directory services systems such as Microsoft Active Directory.|
|IGMP||Internet Group Management Protocol||Provides a mechanism for systems within the same multicast group to register and communicate with each other.|
|DNS||Domain Name System/Service||Resolves hostnames to IP addresses.|
|DHCP||Dynamic Host Configuration Protocol||Automatically assigns TCP/IP information.|
|SNMP||Simple Network Management Protocol||Used in network management systems to monitor network-attached devices for conditions that may need attention from an administrator.|
|TLS||Transport Layer Security||A security protocol designed to ensure privacy between communicating client/server applications.|
|SIP||Session Initiation Protocol||SIP is an application-layer protocol designed to establish and maintain multimedia sessions such as Internet telephony calls.|
|RTP||Real-time Transport Protocol||The Internet-standard protocol for the transport of real-time data.● A dedicated ground, or isolated ground, has only the one outlet connected to it so that a spike sent to ground from one device does not adversely affect another device.|
● Type C fire extinguishers are used for electrical fires.
● The major drawback to gas-based fire suppression systems is that they require sealed environments to operate.
● Main distribution frame (MDF) and intermediate distribution frame (IDF) define types of wiring closets. The main wiring closet for a network typically holds the majority of the network gear, including routers, switches, wiring, servers, and more.
● Cable trays can be used to carry cabling throughout the building. Trays run overhead and usually either resemble racks/wire shelving (having open bottoms) or have solid bottoms to blend in easier with the aesthetics of the environment. Trays are often used when reconfiguration may be a regular thing or it is too costly to run wiring through pipe, walls, and other building fixtures.
Table 4: Standard Business Documents
|SLA (service level agreement)||An agreement between a customer and provider detailing the level of service to be provided on a regular basis and in the event of problems.|
|MOU (memorandum of understanding)||An agreement (bilateral or multilateral) between parties defining terms and conditions of an agreement.|
|MSA (master service agreement)||A contract defining the terms that the parties will use in all future agreements. This speeds negotiations by not requiring negotiations to be repetitively done on broad issues and the only negotiations needed are on deal-specific issues.|
|SOW (statement of work)||A formal document that defines work activities to be performed for a client.|
● Network documentation does not happen by accident; rather, it requires careful planning.
● When creating network documentation, you must keep in mind the audience you are creating the documentation for.
● Documentation is used to take technical information and present it in a manner that someone new (yet qualified) to the network can understand.