List of Figures

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Chapter 1: Local Area Networks

Figure 1.2: Functional elements of Gigabit Ethernet.

Figure 1.3: Token ring configured in a star topology through the use of MAUs.

Figure 1.4: Format of IEEE 802.5 token and frame.

Figure 1.5: ARCnet configuration incorporating both passive and active hubs.

Figure 1.6: Via encapsulation, FDDI can carry Ethernet and token-ring frames as data, providing a multiprotocol backbone network.

Figure 1.7: FDDI layers and their relationship to the seven-layer OSI reference model.

Figure 1.8: FDDI dual-ring topology with three types of interconnecting devices.

Figure 1.9: Self-healing capability of FDDI’s dual-ring topology.

Chapter 2: LAN Administration

Figure 2.1: Information flow between console and agent.

Chapter 3: LAN Restoration Planning

Figure 3.1: A fault tolerant hub-based network.

Chapter 4: Storage Network Management

Figure 4.1: Hierarchical data storage spanning magnetic disk, optical disk, and tape options.

Figure 4.2: A simple SAN spanning the WAN under the supervision of a centralized management system. The access links at each location can be multiples of T1 at 1.544 Mbps (NxT1), a T3 at 45 Mbps or an optical carrier link at 155 Mbps (OC-3). Carrier-provided Ethernet services between 10 Mbps and 1 Gbps can be used as well.

Figure 4.3: For metro-area SANs, SONET/DWDM systems offer the highest resiliency of any transport technology. Even if a fiber gets cut or a node on the ring fails, data gets to its proper destination with very little loss. Data integrity is ensured using higher-level protocols like TCP/IP.

Figure 4.4: Tivoli Storage Network Manager’s event destinations screen.

Chapter 5: Managing Bridges, Routers, Gateways

Figure 5.1: Bridge functionality in reference to the OSI model.

Figure 5.2: Source-route translation bridging, from token ring to Ethernet.

Figure 5.3: Routers operate at the network layer of the OSI reference model.

Figure 5.4: In PIM, streaming content goes out the server one time and is replicated at the RP to reach the nearest subscribers who have specifically requested the stream. This method of content delivery reduces the processing burden of the source server and conserves network bandwidth.

Figure 5.5: A label-switched route is defined by fixed-length tags appended to the data packets. At each hop, the LSR strips the existing label and applies a new label, which tells the next hop how to forward the packet. These labels enable the data packets to be forwarded through the network without the intermediate routers having to perform a complex route lookup based on destination IP address.

Figure 5.6: Gateway functionality in reference to the OSI model.

Figure 5.7: The H.323 protocol stack.

Figure 5.8: Basic H.323 network topology.

Chapter 6: Managing the Wireless Infrastructure

Figure 6.1: The role of a bridge in a wireless network.

Figure 6.2: Relationship of visual line of sight to the Fresnel zone.

Figure 6.3: This four-way handshake occurs between the sending node and the access point or bridge. Its purpose is to minimize the chance of data collisions at the access point or bridge when multiple nodes have data to send.

Figure 6.4: Replay protection via the nonces handshake between a mobility agent and a home agent.

Chapter 7: Managing Voice Systems

Figure 7.1: The PBX as the cornerstone of the corporate voice network. (ACD = automatic call distributor, KTS = key telephone system, SDN = software-defined network, ISDN = integrated services digital network, WATS = wide area telecommunication service, OPX = off-premises extension, FX = foreign exchange, SMDR = station message detail recorder.)

Figure 7.2: Architecture of a single-stage space-division switch. Because the single-stage space division switch always has a path available for the interconnection of inputs to outputs, it may be considered nonblocking. This scheme is acceptable only for small configurations. As the number of cross-points increases to accommodate system growth, the matrix becomes less efficient.

Figure 7.3: The architecture of a three-stage space-division switch. In this type of switch, the probability of blocking is substantially reduced. Although blocking can be further reduced by adding more switching matrices via multiple stages, blocking cannot be eliminated entirely.

Figure 7.4: Centralized system architecture with two local PBXs.

Figure 7.5: Distributed system architecture with multiple PBXs over a wide area.

Figure 7.6: The architecture of AT&T’s Software Defined Network.

Figure 7.7: A typical configuration of a call accounting system. A backup modem is used for polling over the PSTN if the TCP/IP network is unavailable.

Figure 7.8: Detailed view of how the PC poller is configured.

Figure 7.9: A typical wireless PBX system in the corporate environment. In this case, workers can roam between the office and home using the same handset. When the handset moves within range of the local cellular service provider, the signal is handed off from the wireless PBX to the cellular carrier’s nearest base station.

Figure 7.10: An IP gateway connects to the Class 5 central office switch using the industry standard GR-303 interface to extend the reach of Centrex features via the IP.

Chapter 8: Managing the TDM Infrastructure

Figure 8.1: A comparison of TDM and STDM.

Figure 8.2: The interconnectivity potential of a TDM-based T1 multiplexer. (Note: The CSU at each end of the T1 link may be integrated into each multiplexer as a module.)

Figure 8.3: Comparison of processing delay with bit- and byte-oriented multiplexers. With the byte-oriented multiplexer, there is a slight processing delay while the bits are assembled into bytes.

Figure 8.4: DS1 transport via a CO multiplexer and a 3/1 DCS.

Figure 8.5: Typical CCR arrangement, whereby the corporate subscriber manages bandwidth groom-and-fill functions of the DCS network by issuing instructions to the carrier’s central control center from an on-premises terminal.

Chapter 9: Managing Link Performance with CSU-DSUs

Figure 9.1: The original digital signal from a terminal’s serial data output (a) is translated into a bipolar format through AMI (b). The unshaped bipolar waveform is first reduced to a 50% bipolar waveform and then filtered (c), producing an output spectrum with zero energy at the data rate and reducing high-frequency components that may interfere with other services sharing the same cable binder. The output spectrum of a 9.6-Kbps transmission, for example, will exhibit no energy at either dc or 9,600 Hz and will peak at 4,800 Hz.

Figure 9.2: An application of DDS/SC. The secondary channel provides the means through which the diagnostic controller can poll location 3. At the same time, the host, using the primary channel, may poll location 1 for normal production data.

Figure 9.3: An integrated CSU-DSU on a DDS circuit.

Figure 9.4: Deployment of CSUs and regenerators along a T1 span.

Figure 9.5: B8ZS is a line-coding scheme that substitutes a known pattern for eight consecutive zeros. B8ZS maintains the ones-density rule at relatively little bandwidth overhead.

Figure 9.6: A comparison of how the 193rd bit is used in SF (D4) and ESF formats.

Figure 9.7: Frame relay service-level validation from Visual Networks’ Visual UpTime.

Chapter 10: Managing High-Speed Packet Networks

Figure 10.1: A simplified view of virtual circuits through an ATM network.

Figure 10.2: ATM protocol model in relation to the OSI reference model and SONET physical layer protocols.

Figure 10.3: IMA allows the use of bonded multiple T1 access lines into and out of the service provider’s ATM network, rather than forcing companies to use more expensive T3 access lines at each location. This makes it cost-effective for mid-size companies to take advantage of ATM services to support a variety of applications.

Figure 10.4: The network address translation capability of a proxy server allows the creation of subnets with private IP addresses that are locally administered and never exposed to the public Internet. In addition to conserving scarce IP addresses, this capability enhances security by hiding the private IP addresses from public view over the Internet through the use of one or more public IP addresses.

Chapter 11: Network Management Systems

Figure 11.1: Each type of device on the network may have its own EMS, which reports to a central network management system (CNMS) that integrates, prioritizes, and permits analysis of information from multiple element managers.

Figure 11.2: Relationship of SNMP components.

Figure 11.3: MIB Walk from SolarWinds.Net is used to search the SNMP tree for a target device and dump the value of each object identifier (OID). This tool is commonly used to find out what MIBs and OIDs are supported on a particular device. MIB Walk uses a database of MIB information to determine the plain language name for each OID and the MIB to which it belongs.

Figure 11.4: The Ethernet statistics window accessed from Enterasys Networks’ NetSight Element Manager. This window would be used to view a detailed statistical breakdown of traffic on the monitored Ethernet network segment. The data provided applies only to the interface or network segment, either wired or wireless.

Figure 11.5: Physical architecture of the TMN.

Figure 11.6: Tobi Oetiker’s RDDTool showing packet-loss/round-trip delay.

Figure 11.7: Big Sister by Aeby Graeff showing alarms.

Chapter 12: Managing Service Quality

Figure 12.1: In this depiction of QoS reservation, bursty VBR traffic does not cause cell delay for CBR traffic because it is assigned a low-priority (QoS 2) partition of the switching fabric. In this scheme, time-sensitive video traffic always has the right of way.

Figure 12.2: With WFQ, a router’s incoming traffic is classified and arranged in a queue structure according to its type before being released to the network. In this way, WFQ provides consistent response time to heavy and light network users alike without the addition of more bandwidth.

Chapter 13: Managing Network Security

Figure 13.1: The Sony FIU-710 connects to the client via a USB cable and processes, encrypts, and stores fingerprint templates internally rather than in a server or desktop database. If the unit is disconnected from the computer, access is denied.

Figure 13.2: The role of the FIU-710 in the authentication process using a digital certificate.

Figure 13.3: Hackers can use a tool like APSniff to discover essential information about wireless access points, which enables them to more easily break into corporate networks.

Figure 13.4: A firewall protects the enterprise network (trusted) from a variety of attacks emanating from untrusted networks such as the Internet, thereby safeguarding mission-critical resources.

Figure 13.5: Operation of a packet-filtering firewall: (1) inbound/outbound packets are examined for compliance with company-defined security rules; (2) packets found to be in compliance are allowed to pass into the network; (3) packets that are not in compliance are dropped.

Figure 13.6: An implementation of a proxy application.

Figure 13.7: Firewall software for individual computers allows users to control their own level of security. Shown is ZoneAlarm from Zone Labs, which is available for download at the company’s Web site.

Figure 13.8: Network Mapper is an open-source utility developed by Insecure for network exploration or security auditing.

Chapter 14: Network Planning and Design Tools

Figure 14.1: From a library of network shapes (left), items are dragged and dropped into place as needed to design a new node or build a whole network (right). (Source: © 2003 Visio Corp., a division of Microsoft Corp.)

Figure 14.2: Details about network equipment can be stored using custom property fields. Device-specific data for each network shape keeps track of asset, equipment, and manufacturer records that can be accessed from within network diagrams. (Source: © 2003 Visio Corp., a division of Microsoft Corp.)

Figure 14.3: A design tool, such as DesignXpert from NetFormx provides workspace into which objects can be dragged-and-dropped from a device library to start the network design process. ( Source: © 2003 Netformx. Reprinted with permission.)

Chapter 15: WAN Restoration Planning

Figure 15.1: Self-healing SONET-compliant fiber-ring topology. In this scenario, if the inner ring is cut or fails, traffic is rerouted in the opposite direction on the outer ring. The SONET equipment at node D changes the direction of the traffic.

Figure 15.2: Dual points of entry for connections into a building provide protection from cable cuts.

Figure 15.3: Configuration for ISDN backup for a T1 private line.

Figure 15.4: Dial backup communications link between multiplexer nodes.

Figure 15.5: Devices that provide IMA now support trunk group failure protection, allowing communication to continue despite the failure of one or more access lines in the trunk group. (In the bottom diagram, the failed line is indicated with an X.)

Chapter 16: Maintenance and Support Services

Figure 16.1: Users can submit trouble reports from a Web form posted on the company’s intranet. (Source: © 2003 HelpSTAR.com. Reprinted with permission.)

Figure 16.2: A simple configuration showing the relationship of the AP to the wired and wireless segments of the network.

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