Ch. 4 LAN Review

Local Area Networks were originally point-to-point, much as airplane travel was before the advent of the ______ as a hub.

Data communication in the 1970s was a costly venture, as bandwidth, disk storage, and printers were ______.

For the past 25 years, the process industries have had large numbers of “smart” devices that communicate electrically to monitor or control a process or processes. The combination of such devices and the electrical connectivity that enables them to communicate is, by definition, a ______.

Industrial LANs seem to be everywhere and every instrument manufacturer has a proprietary ______.

In addition to the vendor-proprietary LANs, there are now several standards for industrial LANs, including: FOUNDATION Fieldbus, PROFIBUS and PROFINET, plus Modbus/TCP, and ______.

Programmable controllers can be used to form a distributed control system when they are connected by a local area network with a third-party human-machine interface to provide integration and a graphics ______.

We prefer the following definition: If a company owns the medium of transmission, the infrastructure, and three or more devices that are in communication, it has a ______.

An alternate definition of local area network is this: a system with more than three nodes that uses a protocol with defined rules and performs a specified set of ______.

THE IEEE 802 MODEL IS A LAYER 1 AND 2 MODEL CONCERNING ITSELF, FROM INCEPTION TO THIS DAY, WITH VARIABLE SIZE PACKET NETWORKS. ONE SHOULD FIRST LOOK AT THE OPEN SYSTEMS INTERCONNECT ISO 7498 MODEL AND THE IEEE 802 MODEL, TO DISCOVER HOW THESE MODELS COMPLEMENT ONE ANOTHER. THE 802 STANDARD DESCRIBES NETWORK ______.

The current 802 standard describes network ______.

802.11a used the ______ band, which provided up to 54 Mbps

802.11b provided 11 Mbps transmission in the ______ band using DSSS

802.11g works in the ______ band but has a maximum data rate of 54 Mbps

802.11n is capable of achieving a data rate of up to ______ Mbps

IEEE 802.11ac-2013 includes wider channels in the ______ band

IEEE 802.11ad defines a new physical layer for 802.11 networks to operate in the ______ GHz millimeter wave spectrum

IEEE 802.11af allows WLAN operation in the TV white space spectrum in the ______ and UHF bands

IEEE 802.11ah defines a WLAN system operating at sub-GHz license-exempt bands, with final approval slated for ______

WiMAX is a metropolitan area network standard meant to cover much larger areas than the 802.11 standards. Standard IEEE 802.16 was approved in 2002 for operation over a broad frequency range of ______ to 66 GHz

A wireless mesh network is a communications network made up of radio nodes organized into a ______ topology

The mesh clients are often laptops, cell phones, and other wireless devices; the mesh routers forward traffic to and from the gateways which may, but need not, connect to the ______

Wireless mesh networks can be implemented with various wireless technologies including 802.11, 802.15, ______

Layer 2 of the ISO model is the __________ Layer

Broadband refers to separating signals by __________ or time

Analog or digital broadband trunks offer a multitude of services—data, voice, and __________

In baseband transmission, there is only one __________ signal on the bus or shared medium

Switching is accomplished by using a fast-switching __________, which is a set of electronic switches arranged so there can be a path from any port to another port depending upon a signal-contained address

Another method of sharing is a __________ method, wherein everyone is allowed to grab the channel for a short period of time if it is currently idle

This kind of sharing method is like getting to an intersection and going right across if there is no cross traffic or dashing across as soon as there is a break in traffic

Used in industrial environments, carrier band has only a single __________ on the bus, which is used to translate the digital signal away from a DC reference

Broadband services can include network technology for multiple LANs on one __________

The bulk of the technology found in an analog frequency division, multiplexing LAN evolved directly from __________ TV systems, right down to the connectors and the 75-ohm cable

If data is placed digitally at a bit rate that approaches the bandwidth capacity of the channel, it is a __________ system

The main bus connects the devices in the network and it will have a large number of different ______ on it

Carrier band uses ______ cable

Most broadband systems use the ______ topology

The star topology has been a fundamental computer network topology since the computer joined ______

A physical ring is comprised of point-to-point connections and each device in the network is in the path of data ______

Due to the fact that fiber optic cable is not open to easy line taps, terminations are difficult, and most fiber connections are considered a ______ connection

The bus topology is used extensively in ______

Ethernet switches are essentially powerful computers with large numbers of Ethernet network interface cards, whose function is to take incoming Ethernet frames from connected computers and pass them back out to their intended destinations based on the ______ addresses in the frames

The traditional twisted-pair telephone wiring was investigated carefully by early network designers because of the tremendous savings that could be realized if the already installed media could be used instead of special ______

Categories are, for our purposes, defined in IEC 11801 and assign the maximum data rate a cable is capable of carrying over a stated ______

Having successfully conquered the office and business environment, Ethernet has continued on to assume a large share in the industrial ______

The original 802.11 standard provided for 1 or 2 Mbps transmission in the 2.4 GHz band using either frequency hopping spread spectrum or direct sequence spread ______

The original 802.11 standard is now a legacy; there is no 802.11 standard anymore, just the amendments, due to the marketplace availability of much higher data ______

In the token-passing access method, a short message with a unique digital pattern is transferred from peer-to-peer among all the participating ______

Token passing is ______; every station knows when the token will arrive, so it knows within a specified period of time when it will receive a transmission initiated by another station

Carrier Sense Multiple Access with Collision Detection is interpreted as meaning “10 Mbps, Baseband, 500 m end-to-end,” using Belden 89880 coaxial cable, also known as ThickNet or, if you will, “the frozen orange garden hose”—a reference to the difficulty in handling that this particular cable presents The cable impedance is 50 ohms and it must be terminated at each end in a 50-ohm non-inductive precision ______

10BASE2 is interpreted as “10 Mbps, Baseband, 185 m end-toend,” using RG58A/U coaxial cable, also called ThinNet The coaxial cable is terminated in 50-ohm ______ at each end node, the node being connected by a BNC “T” connector, which is attached to the NIC

10BASE-FL is “10 Mbps Ethernet over ______.” It requires one transmit and one receive fiber and uses an optical switching hub Depending on the fiber cable used, 10BASE-FL may have a maximum distance of nearly 2 ______

100BASE-T specifications are generally identical to 10BASE-T, with the exception that the connecting cable must be Category ______ , as opposed to Category 3 for 10 Mbps

Event-Driven Polling Token Passing In the token-passing access method, a short message with a unique digital pattern is transferred from -to- among all the participating peers

IEEE 802.3 is not specifically an industrial protocol as such, it is used throughout ______ today

10BASE5 is interpreted as meaning “10 Mbps, Baseband, 500 m end-to-end ,” using Belden 89880 coaxial cable, also known as ThickNet or, if you will, “the ______ orange garden hose”—a reference to the difficulty in handling that this particular cable presents

ThinNet/10BASE2 is usually much easier to work with than ThickNet; however, it does have two cables coming into the back of each ______, aside from the end ones

The node NIC is connected to the hub or switch with a 100ohm, UTP Category 3 cable, using only two pair of the fourpair cable Due to the prevalence and low cost of Ethernet NICs capable of “fast” Ethernet, this standard is also considered ______ but most NICs support 10/100BASE-T and can drop down to 10 Mbps if needed

100BASE-FX This is “100 Mbps Ethernet over ______.” When run in full duplex mode, 100BASE-FX can achieve a distance of 2 km Half-duplex is limited to 400 ______

A repeater is a Layer 1 device that regenerates the input signal, thus restoring its ______ and clock sequence

A bridge consists of a repeater with intelligence that reads the Layer 2 information: the destination and source adapter addresses; the “type or length” field; and the frame check ______, which is a cyclic redundancy check

A switch is essentially a bridge with a large number of Ethernet NICs. Like a bridge, the switch learns the MAC addresses of the devices on each of its ports and, just like a bridge, a switch examines the Layer 2 addresses to decide where the destination node is ______

A router contains logic that examines Layers 1, 2, and 3 information and will connect two or more networks, providing network addressing, error correction, physical signal conversion, and conversion to compensate for differences in signal frame ______

A Layer 3 switch is a device capable of reading Layer 2 and Layer 3 addresses, so it knows whether the message is to stay on the same physical segment of a network, to be bridged to another physical segment , or to leave for another ______

The organization of 1s and 0s on System A may vary considerably with that of System B. The protocols and addressing may be quite different. In order to accommodate the differences, it takes a dual transceiver, that is, it takes all seven layers for each network to produce the native data, which can then be sent back down the other ______

An important and common use of gateways in industrial settings is to connect incompatible networks to allow for data exchange using only three layers of the seven-layer OSI ______

In the SCADA world, gateway devices can be used to perform protocol conversion so that, for example, a SCADA system that uses asynchronous, serial DNP3.0 protocol to poll its remote terminal units can communicate with an RTU that only supports asynchronous, serial Modbus ______

We briefly mentioned some of the Layer 2 functions when discussing the bridge. At this point, we will take a more detailed look at Layer 2 operation MEDIA ACCESS MEANS HOW A DEVICE ON A NETWORK, SUCH AS A LAN, GAINS CONTROL OF THE NETWORK MEDIA IN ORDER TO TRANSMIT ITS INFORMATION—IN OTHER WORDS, WHO TALKS AND WHEN MANY DIFFERENT METHODS ARE AVAILABLE FOR GAINING ACCESS AND MOST DEPEND ON NETWORK PHILOSOPHY , NOT NECESSARILY ON NETWORK ______

ALTHOUGH POLLING MAY BE ONE OF THE OLDEST ACCESS METHODS, IT IS STILL USED AND, IN CERTAIN SITUATIONS, QUITE EFFECTIVELY IN POLLING, A SCHEDULER, WHETHER A SOFTWARE OR HARDWARE ENTITY , DETERMINES WHO SHOULD SPEAK, WHO SHOULD LISTEN, AND UNDER WHAT CONDITIONS POLLING CONSISTS OF A PRIMARY NODE ASKING ONE OR MORE SECONDARY NODES , EACH IN TURN, IF THEY HAVE ANY TRAFFIC TO ______

AN EXAMPLE OF A MODIFIED METHOD IS INTERRUPT POLLING, ALSO KNOWN AS EVENT-DRIVEN POLLING OR “HUBBING. ______

1000BASE-T requires a tighter specification cable, such as Category 5e or 6a, to operate properly over copper at 100 m, its maximum distance. Note that all four pairs of the cable are used. 1000BASE-CX is a shielded twisted-pair cable with a 25 m maximum distance. It is no longer considered an active specification. 1000BASE-SX is a short-wavelength fiber cable with a maximum distance of up to ______.

1000BASE-LX is a long-wavelength fiber cable with a maximum distance of up to ______.

10GbE – 10 Gigabit Ethernet Over Fiber includes several variations and designations: 10GbBASE-SR, 10GbBASE-LR, 10GbBASE-LRM, 10GbBASE-ER, 10GbBASE-LX4, and 10GbBASE-PR. 10GbBASE-SR was developed to run on multi-mode fiber for a distance of ______.

Due to both monetary and certain installation requirements, a copper version of the 10 GbE was developed for unshielded twisted pair. The standard was known as 10GBASE-T and was published in September IEEE 802 Media Access Control. The media access control sublayer interfaces the Logical Link Control sublayer with the Physical layer. The MAC logic provides the service of sending and receiving 1s and 0s by arranging them into frames. In transmit mode, the MAC: Initiates transmission, Assembles the frame, Calculates the Frame Check Sequence, Sends the frame, and Ceases transmitting. In both transmit and receive modes, the Media Access Control logic also monitors for collisions and executes the applicable recovery logic based on the mode. It is the MAC layer that is primarily responsible for the media access method—token bus or CSMA/CD—hence its name: Media Access Control. The server software had algorithms to determine priority, level of access, and so on IEEE 802 Media Access Control This could be rectified by using multiple servers or by reducing the server software so the station that was acting as the server could also be used as a station and, therefore, the responsibility for being server could be moved around. In practice, a single station or set of stations must have the management responsibility for LAN additions, deletions, security and so forth. Industrial Token Passing One of the other methods of access used in industrial networking is token passing. It is deterministic and operates efficiently even at heavy loads. However, it is a much slower protocol, even though it is deterministic, because all nodes are offered a chance to transmit, even if they have no need, and that wastes bandwidth. Token-Passing Bus The token-passing bus actually does what its name implies. The token will be passed to the next rider when the present token holder gets off, so that the next person may ride the bus. Although most of the legacy IEEE 802.4 standard described a “medium” as a broadband coaxial cable with repeaters, it should be understood that token-passing buses use other media. The scheme described next is a generalized concept that a token-passing bus might use. One of the important parameters of a token-passing system is the token rotation time—the time it takes the token to make a round trip of the bus. Token-Passing Bus Some networks have a four-level priority scheme in effect; that is, starting at the highest and going to the lowest, a station transmits its high-priority packets first. If there is time left on the token-hold timer that corresponds to that priority, then the station can transmit its lower-priority packets. Without the priority scheme, all messages have the same high priority and all use the high-priority token timer. At intervals, a “solicit successor” frame is sent and allows one response frame. Stations whose address falls into this range can then respond with a set successor frame. Logical Link Control Together, the MAC and the Logical Link Control are responsible for placing and retrieving information without errors on the Physical layer. The specifications in IEEE 802.2 outline the LLC’s responsibilities, regardless of which media access/topology is employed, for any. The functional definition of the Data Link layer includes framing data blocks or packets, determining the check character, and determining network addresses. Introduction to Types of Service “Connection-oriented” service means service that is point-to-point oriented. On the other hand, “connectionless” service places addressed packets on the media without establishing a persistent data channel. Type 1: Connectionless service allows two LLCs. Connection-oriented service is point-to-point oriented. On the other hand, connectionless service places addressed packets on the media without establishing a persistent data channel. Type 1: Connectionless service allows two LLCs.

Due to both monetary and certain installation requirements, a copper version of the 10 GbE was developed for unshielded twisted pair. The standard was known as 10GBASE-T and was published in September IEEE 802 Media Access Control. The media access control sublayer interfaces the Logical Link Control sublayer with the Physical layer. The MAC logic provides the service of sending and receiving 1s and 0s by arranging them into frames. In transmit mode, the MAC: Initiates transmission, Assembles the frame, Calculates the Frame Check Sequence, Sends the frame, and Ceases transmitting. In both transmit and receive modes, the Media Access Control logic also monitors for collisions and executes the applicable recovery logic based on the mode. It is the ______ layer that is primarily responsible for the media access method—token bus or CSMA/CD—hence its name: Media Access Control.

The server software had algorithms to determine priority, level of access, and so on IEEE 802 Media Access Control This could be rectified by using multiple servers or by reducing the server software so the station that was acting as the server could also be used as a station and, therefore, the responsibility for being server could be moved around. In practice, a single station or set of stations must have the management responsibility for LAN additions, deletions, security and so forth. Industrial Token Passing One of the other methods of access used in industrial networking is token passing. It is deterministic and operates efficiently even at heavy loads. However, it is a much slower protocol, even though it is deterministic, because all nodes are offered a chance to transmit, even if they have no need, and that wastes bandwidth. Token-Passing Bus The token-passing bus actually does what its name implies. The token will be passed to the next rider when the present token holder gets off, so that the next person may ride the bus. Although most of the legacy IEEE 802.4 standard described a “medium” as a broadband coaxial cable with repeaters, it should be understood that token-passing buses use other media. The scheme described next is a generalized concept that a token-passing bus might use. One of the important parameters of a token-passing system is the token rotation time—the time it takes the token to make a round trip of the bus. Token-Passing Bus Some networks have a four-level priority scheme in effect; that is, starting at the highest and going to the lowest, a station transmits its high-priority packets first. If there is time left on the token-hold timer that corresponds to that priority, then the station can transmit its lower-priority packets. Without the priority scheme, all messages have the same high priority and all use the high-priority token timer. At intervals, a “solicit successor” frame is sent and allows one response frame. Stations whose address falls into this range can then respond with a set successor frame. Logical Link Control Together, the ______ and the Logical Link Control are responsible for placing and retrieving information without errors on the Physical layer. The specifications in IEEE 802.2 outline the LLC’s responsibilities, regardless of which media access/topology is employed, for any. The functional definition of the Data Link layer includes framing data blocks or packets, determining the check character, and determining network addresses.

Introduction to Types of Service “Connection-oriented” service means service that is point-to-point oriented. On the other hand, “connectionless” service places addressed packets on the media without establishing a persistent data channel. Type 1: Connectionless service allows two LLCs. Connection-oriented service is ______ oriented. On the other hand, connectionless service places addressed packets on the media without establishing a persistent data channel. Type 1: Connectionless service allows two LLCs.