Making Decisions as Part of the Top Down Network Design Process

The next few chapters provide guidelines for selecting network design solutions for a customer. The decisions you make regarding protocols and technologies should be based on the information you have gathered on your customer's business and technical goals. Researchers studying decision models say that one of the most important aspects of making a sound decision is having a good list of goals. In her book The Can-Do Manager, published by the American Management Association, Tess Kirby says that...

Constraints on Scalability

When analyzing a customer's scalability goals, it is important to keep in mind that there are impediments to scalability inherent in networking technologies. Selecting technologies that can meet a customer's scalability goals is a complex process with significant ramifications if not done correctly. For example, selecting a flat network topology with Layer 2 switches can cause problems as the number of users scales, especially if the users' applications or network protocols send numerous...

Expanding Access to Data

Chapter 1, Analyzing Business Goals and Constraints, talked about a common business goal of expanding access to data for employees who use enterprise networks. Managers empower employees to make strategic decisions that require access to sales, marketing, engineering, and financial data. Traditionally this data was stored on departmental LANs. Today this data is often stored on centralized servers. For years, networking books and training classes taught the 80 20 rule for capacity planning 80...

Redundant Network Design Topologies

Redundant network designs let you meet requirements for network availability by duplicating elements in a network. Redundancy attempts to eliminate any single point of failure on the network. The goal is to duplicate any required component whose failure could disable critical applications. The component could be a core router, a switch, a link between two switches, a channel service unit (CSU), a power supply, a WAN trunk, Internet connectivity, and so on. To enable business survivability after...

Apple Talk Routing

AppleTalk networks have three options for routing Routing Table Maintenance Protocol (RTMP) AppleTalk Update-Based Routing Protocol (AURP) RTMP is the most common option for networks that still use AppleTalk, including many university netwc and is supported by most vendors of multiprotocol routers and servers that do routing. To reduce the a large enterprises have the option of using AURP or EIGRP in the core of their internetworks. AURP is rar still supported by Cisco. Static routes are also...

Distributed Computing Traffic Flow

Distributed computing refers to applications that require multiple computing nodes working together to complete a job. Some complex modeling and rendering tasks cannot be accomplished in a reasonable timeframe unless multiple computers process data and run algorithms simultaneously. The visual effects for movies are often developed in a distributed-computing environment. Distributed computing is also used in the semiconductor industry to serve the extreme computing needs of microchip design and...

STP Convergence

Switches follow four steps to converge the topology into a spanning tree 1. The switches elect a single switch as the root bridge. 2. The switches elect a port on each switch (known as the root port) that provides the lowest-cost to the root bridge. 3. For each LAN segment, the switches elect a designated bridge and a designated port on that swi The designated port is a port on the LAN segment that has the lowest-cost path to the root bride The designated port forwards frames from the LAN...

Frame Relay Huband Spoke Topologies and Subinterfaces

Frame Relay networks are often designed in a hub-and-spoke topology, such as the topology shown in Figure 11-7. A central-site router in this topology can have many logical connections to remote sites with only one physical connection to the WAN, thus simplifying installation and management. Figure 11-7. A Frame Relay Hub-and-Spoke Topology One problem with a hub-and-spoke topology is that split horizon can limit routing. With split horizon, distance-vector routing protocols do not repeat...

Characterizing the Network Infrastructure

Characterizing the infrastructure of a network means developing a set of network maps and learning the location of major internetworking devices and network segments. It also includes documenting the names and addresses of major devices and segments, and identifying any standard methods for addressing and naming. Documenting the types and lengths of physical cabling and investigating architectural and environmental constraints are also important aspects of characterizing the network...

IETF Integrated Services Working Group Quality of Service Specifications

In an IP environment, you can use the work that the IETF Integrated Services working group is doing on QoS requirements. In RFC 2205, the working group describes the Resource Reservation Protocol (RSVP). In RFC 2208, the working group provides information on the applicability of rSvp and some guidelines for deploying it. RFCs 2209 through 2216 are also related to supporting QoS on the Internet and intranets. RSVP is a setup protocol used by a host to request specific qualities of service from...

Characterizing Wiring and Media

To help you meet scalability and availability goals for your new network design, it is important to understand the cabling design and wiring of the existing network. Documenting the existing cabling design can help you plan for enhancements and identify any potential problems. If possible, you should document the types of cabling in use as well as cable distances. Distance information is useful when selecting data link layer technologies based on distance restrictions. While exploring the...

Thin Client Traffic Flow

A special case of the client server architecture is a thin client, which is software or hardware that is designed to be particularly simple and to work in an environment where the bulk of data processing occurs on a server. With thin client technology, (also known as server-based computing), user applications originate on a central server. In some cases, the application runs on the central server, and, in other cases, the software is installed on the server and is downloaded into the client...

Characterizing Traffic Flow

Characterizing traffic flow involves identifying sources and destinations of network traffic and analyzing the direction and symmetry of data traveling between sources and destinations. In some applications, the flow is bidirectional and symmetric. (Both ends of the flow send traffic at about the same rate.) In other applications, the flow is bidirectional and asymmetric. Client stations send small queries and servers send large streams of data. In a broadcast application, the flow is...

Traffic Flow in Voice over IP Networks

Traffic flow in Voice over IP (VoIP) networks can be quite complicated. This section briefly discusses VoIP from a traffic flow point of view. The most important concept to understand when considering traffic flow in VoIP networks is that there are multiple flows. The flow associated with transmitting the audio voice is separate from the flows associated with call setup and teardown. The flow for transmitting the digital voice is essentially peer-to-peer, between two phones or PCs running...

Identifying Major Traffic Sources and Stores

To understand network traffic flow, you should first identify user communities and data stores for existing and new applications. Chapter 3, Characterizing the Existing Internetwork, talked about locating major hosts, interconnect devices, and network segments on a customer's network. The tasks discussed in Chapter 3 facilitate the tasks discussed in this chapter of identifying major user communities and data stores. A user community is a set of workers who use a particular application or set...

Characterizing Network Traffic

This chapter describes techniques for characterizing traffic flow, traffic volume, and protocol behavior. The techniques include recognizing traffic sources and data stores, documenting application and protocol usage, and evaluating network traffic caused by common protocols. Upon completion of this chapter, you will be able to analyze network traffic patterns to help you select appropriate logical and physical network design solutions to meet a customer's goals. The previous chapter talked...

Analyzing Network Efficiency

Chapter 2 talked about the importance of using maximum frame sizes to increase network efficiency. Bandwidth utilization is optimized for efficiency when applications and protocols are configured to send large amounts of data per frame, thus minimizing the number of frames and round-trip delays required for a transaction. The number of frames per transaction can also be minimized if the receiver is configured with a large receive window allowing it to accept multiple frames before it must send...

Traffic Characteristics of the Existing WAN

As Klamath has grown over the years, network performance has degraded. Users report that the network is slow, especially during the busiest hour between 10 and 11 a.m. Users of the SNA manufacturing support system report that it sometimes takes 2 or 3 minutes for their screens to unlock after they enter information. Users of the Novell sales order-entry system and the TCP IP financial modeling applications also report slow response times. A WAN protocol analyzer was used at each of the major...

Appendix B References and Recommended Reading

DNS and BIND, 4th ed. Sebastopol, California O'Reilly & Associates, Inc. 2001. Berkowitz, H. WAN Survival Guide. New York, New York John Wiley & Sons, Inc. 2001. Buchanan, R. The Art of Testing Network Systems. New York, New York John Wiley & Sons, Inc. 1996. Clark, K. and K. Hamilton. Cisco LAN Switching. Indianapolis, Indiana Cisco Press, Comer, D.E. Internetworking with TCP IP Principles, Protocols, and Architecture, Volume I, 4th ed. Englewood Cliffs, New...

Hmn

SYMBOL A B C D E F G H I J K L M N O P Q R S I U V W X Y Z (Internet Corporation for Assigned Names and Numbers) ICMP (Internet Control Message Protocol) echo requests router solicitation packet ICSA labs idle time (intrusion detection system) security design 2nd 3rd IDSL (ISDN DSL) IEEE 802.1p classifying LAN traffic 2nd 3rd IEEE 802.1Q document (VLAN ID frame tagging) 2nd IEEE 802.1X wireless network authentication 2nd 3rd 4th IEEE 802.3 (Ethernet LANs technology) 2nd IEEE 802.5 (Internet...

Identifying the Scope of a Network Design Project

One of the first steps in starting a network design project is to determine its scope. Some of the most common network design projects these days are small in scope for example, projects to allow a few people in a sales office to access the enterprise network via a VPN. On the other hand, some design projects are large in scope. Ask your customer to help you understand if the design is for a single network segment, a set of LANs, a set of WAN or remote-access networks, or the entire enterprise...

Tpt

SYMBOL A B C D E F G H I J K L M N O P Q R S T U V W X Y Z SAA (Service Assurance Agent) 2nd 3rd SACK (Secure Architecture for Enterprises) scalability convergence 2nd technical goals constraints 2nd data access 2nd 3rd expansion planning 2nd scaling STP (Spanning Tree Protocol) 2nd Rapid Reconfiguration 2nd schedules network design 2nd 3rd 4th project scope documentation 2nd scripts (Synchronous Digital Hierarchy) 2nd SDSL (symmetric DSL) secret keys section layers SONET (SSL) security 2nd...

Dynamic Inter Switch Link Protocol

With early versions of ISL, you had to manually enable ISL at both ends of a trunk. In more recent versions of Cisco switching software, the Cisco proprietary Dynamic Inter-Switch Link (DISL) protocol supports a switch negotiating with the remote side to enable or disable ISL. DISL should be recommended to your design customers, but be careful with its configuration. ISL on a trunk interface can be set to on, off, desirable, auto, and nonegotiate. Nonegotiate enables ISL but does not send any...

Documenting Traffic Flow on the Existing Network

Documenting traffic flow involves identifying and characterizing individual traffic flows between traffic sources and stores. Traffic flows have recently become a hot topic for discussion in the Internet community. A lot of progress is being made on defining flows, measuring flow behavior, and allowing an end station to specify performance requirements for flows. To understand traffic flow behavior better, you can read Request For Comments (RFC) 2722, Traffic Flow Measurement Architecture. RFC...

Dynamic Versus Static and Default Routing

A static route is a route that is manually configured and does not rely on updates from a routing protoc necessary to use a routing protocol. Static routes are often used to connect to a stub network. A stub n internetwork and isn't used as a transit path for traffic trying to get anywhere else. An example of a stu connects to the Internet via a single link to an Internet service provider (ISP). The ISP can have a stati necessary to run a routing protocol between the company and the ISP. A...

Remote Monitoring RMON

The RMON MIB was developed by the IETF in the early 1990s to address shortcomings in the standard MIBs, which lacked the ability to provide statistics on data link and physical layer parameters. The IETF originally developed the RMON MIB to provide Ethernet traffic statistics and fault diagnosis. In 1994, Token Ring statistics were added. RMON agents gather statistics on cyclic redundancy check (CRC) errors, Ethernet collisions, Token Ring soft errors, packet-size distribution, the number of...

Split Horizon Hold Down and Poison Reverse Features of Distance Vector Protocols

A router running a distance-vector protocol sends its routing table out each of its ports on a periodic ba split-horizon technique, the router sends only routes that are reachable via other ports. This reduces th importantly, improves the accuracy of routing information. With split horizon, a router does not tell ano better learned locally. Most distance-vector protocols also implement a hold-down timer so that new information about a rout< believed right away, in case the information is...

Estimating Traffic Load Caused by Routing Protocols

At this point in the network design process, you might not have selected routing protocols for the new network design, but you should have identified routing protocols running on the existing network. To help you characterize network traffic caused by routing protocols, Table 4-7 shows the amount of bandwidth used by legacy distance-vector routing protocols. Table 4-7. Bandwidth Used by Legacy Routing Protocols Table 4-7. Bandwidth Used by Legacy Routing Protocols Estimating traffic load caused...

Meeting Security Goals with Firewall Topologies

Dmz Topology

A firewall is a system or combination of systems that enforces a boundary between two or more networks. A firewall can be a router with access control lists (ACLs), a dedicated hardware box, or software running on a PC or UNIX system. A firewall should be placed in the network topology so that all traffic from outside the protected network must pass through the firewall. A security policy specifies which traffic is authorized to pass through the firewall. Firewalls are especially important at...

Changes in Enterprise Networks

Enterprise networks at many corporations have been undergoing major changes. The value of making vast amounts of data available to employees, customers, and business partners has been recognized. Corporate employees, field employees, contract employees, and telecommuters need access to sales, marketing, engineering, and financial data, regardless of whether the data is stored on centralized or distributed servers or mainframes. Suppliers, vendors, and customers also need access to many types of...

Redistribution Between Routing Protocols

Redistribution allows routers to run more than one routing protocol and share routes among routing pro redistribution can be challenging because every routing protocol behaves differently and routing protoco information about routes, prefixes, metrics, link states, and so on. Redistribution can lead to routing loc can complicate planning and troubleshooting. Despite the challenges, redistribution may be desirable when connecting different layers of the hierarch new routing protocol, when...

Project Scheduling

An additional business-oriented topic that you should review with your customer is the timeframe for the network design project. When is the final due date and what are the intermediate and major milestones In most cases, management of the project schedule is the customer's obligation, not yours, but you should ask the customer to give you a copy of the schedule and to keep you informed about any slips in the schedule. It's important to include intermediate milestones in the project schedule....

Selecting a WAN Service Provider

In addition to selecting technologies and devices for a WAN network design, you must also select service providers or carriers. One obvious criterion for selecting a service provider is the cost of services. Using cost as the main selection criterion, however, can make the choice difficult because providers offer distinct services and define terms and conditions differently. Also, for many network designs, cost is not the main criterion. The following criteria are often more important than cost...

Using a Top Down Network Design Methodology

The world we've made as a result of the level of thinking we have done thus far creates problems that we cannot solve at the same level at which we created them. To paraphrase Einstein, networking professionals have the ability to create networks that are so complex that when problems arise they can't be solved using the same sort of thinking that was used to create the networks. Add to this the fact that each upgrade, patch, and modification to a network can also be created using complex and...

Using an Unpublished Service Set Identifier

Every WLAN has an SSID that identifies it. To gain access to a wireless LAN, a client must know the correct SSID. Some network administrators rely on this as a method for security even though it doesn't truly authenticate the client and doesn't provide any data privacy. Also, an eavesdropper can easily determine the SSID with the use of a wireless protocol analyzer, such as WildPackets's AiroPeek product. The SSID is advertised in plain text in beacon messages that the access point sends. Some...

Causes of Delay

Any goals regarding delay must take into account fundamental physics. Despite science fiction stories that say differently, any signal experiences a propagation delay resulting from the finite speed of light, which is about 300,000 kilometers per second (or 186,000 miles per second for metric-challenged readers in the United States). Network designers can also remember 1 nanosecond per foot. These values are for light traveling in a vacuum. A signal in a cable or optical fiber travels...

Characterizing Routing Protocols

All routing protocols have the same general goal to share network reachability information among rout goal in a variety of ways. Some routing protocols send a complete routing table to other routers. Other information on the status of directly connected links. Some routing protocols send periodic hello packet routers. Some routing protocols include advanced information such as a subnet mask or prefix length w protocols share dynamic (learned) information, but in some cases, static configuration...

Network Traffic Checklist

You can use the following Network Traffic checklist to determine if you have completed all the steps for characterizing network traffic l- I have identified major traffic sources and stores and documented traffic flow between them. I. I have categorized the traffic flow for each application as being terminal host, client server, peer-to-peer, server server, or distributed computing. I- I have estimated the bandwidth requirements for each application. I. I have estimated bandwidth requirements...

Checking the Status of Major Routers Switches and Firewalls

The final step in characterizing the existing internetwork is to check the behavior of the internetworking devices in the internetwork. This includes routers and switches that connect layers of a hierarchical topology, backbone routers and switches, and routers, switches, and firewalls that will have the most significant roles in your new network design. It's not necessary to check every LAN switch, just the major switches, routers, and firewalls. Checking the behavior and health of an...

Characterizing the Existing Internetwork

If we could first know where we are and whither we are tending, we could better judge what to do and how to do it. An important step in top-down network design is to examine a customer's existing network to better judge how to meet expectations for network scalability, performance, and availability. Examining the existing network includes learning about the topology and physical structure and assessing the network's performance. By developing an understanding of the existing network's...

Distance Vector Versus Link State Routing Protocols

Routing protocols fall into two major classes distance-vector protocols and link-state protocols. This ch protocols first. The following protocols are distance-vector protocols (or derivatives of distance-vector protocols) IP Routing Information Protocol (RIP) version 1 and 2 IP Interior Gateway Routing Protocol (IGRP) IP Enhanced IGRP (EIGRP) (an advanced distance-vector protocol) IP Border Gateway Protocol (BGP) (a path-vector routing protocol) Novell NetWare Internetwork Packet Exchange...

Identifying a Customers Network Applications

At this point in the design process, you have identified your customer's business goals and the scope of the project. It is now time to focus on the real reason networks exist applications. The identification of your customer's applications should include both current applications and new applications. Ask your customer to help you fill out a chart, such as the one in Table 1-1. Table 1-1 identifies network applications. In Chapters 2 and 4, it will be enhanced to include technical requirements...

NetBIOS NetBEUI Packets

Table A-5 shows the packets that a NetBIOS (NetBEUI) station sends and receives when it boots. In a Windows environment, Server Message Block (SMB) session-initialization packets follow the NetBIOS packets. The SMB packets are not shown. Table A-5. Packets for NetBIOS (NetBEUI) Client Initialization Check name (make sure own name is unique)

The Wireless Network

The wireless enhancements to the network represented the biggest challenge due to biases and other Layer 8 (nontechnical issues). The IT department preferred a single solution that was extremely secure. Many students and faculty wanted secure access to the campus network and support for visitors using the wireless network to access the Internet. The solution was to provide two access points in each building, with different security policies implemented on them. An open access point in each...

Measuring Bandwidth Utilization by Protocol

Network Utilization in Hour Intervals Developing a baseline of network performance should also include measuring utilization from broadcast traffic versus unicast traffic, and by each major protocol. As discussed in Chapter 4, some protocols send excessive broadcast traffic, which can seriously degrade performance, especially on switched networks. To measure bandwidth utilization by protocol, place a protocol analyzer or remote monitoring (RMON) probe on each major network segment...

Gigabit Ethernet

Gigabit Ethernet was originally defined in the IEEE 802.3z standard and is now merged into the 2002 edition of IEEE 802.3. It operates essentially like 100-Mbps Ethernet, except that it is 10 times faster. It uses CSMA CD with support for one repeater per collision domain, and handles both half- and full-duplex operations. It uses a standard 802.3 frame format and frame size. To avoid the need to reduce the size of a half-duplex Gigabit Ethernet network to 1 10th the size of a 100-Mbps Ethernet...

Selecting Internetworking Devices for a Campus Network Design

At this point in the network design process, you have developed a network topology and should have an idea of which segments will be shared with hubs or repeaters, bridged with bridges or switches, or routed using routers. Table 10-6 provides a review of the major differences between hubs (repeaters), bridges, switches, and routers. Table 10-6. Comparing Hubs, Bridges, Switches, and Routers Table 10-6. Comparing Hubs, Bridges, Switches, and Routers All ports are in the same bandwidth domain....

Types of Cables

Three major types of cables are used in campus network implementations Shielded copper, including shielded twisted-pair (STP), coaxial (coax), and twin-axial (twinax) cables Unshielded copper (typically UTP) cables STP cabling was widely used in Token Ring networks in the 1980s and 1990s. Most Token Ring networks have been replaced by Ethernet networks these days. Ethernet generally uses UTP and fiber-optic cabling, although it is possible to make Ethernet work on STP cabling. (The fact that...

Multihoming the Internet Connection

The generic meaning of multihoming is to provide more than one connection for a system to access and offer network services. The term multihoming is used in many specific ways also. A server, for example, is said to be multihomed if it has more than one network layer address. Content delivery networks can multihome application layer data and services. The term multihoming is increasingly being used to refer to the practice of providing an enterprise network more than one entry into the...

Mesh Versus Hierarchical Mesh Topologies

Partial And Full Mesh Topology

Network designers often recommend a mesh topology to meet availability requirements. In a full-mesh topology, every router or switch is connected to every other router or switch. A full-mesh network provides complete redundancy, and offers good performance because there is just a single-link delay between any two sites. A partial-mesh network has fewer connections. To reach another router or switch in a partial-mesh network might require traversing intermediate links, as shown in Figure 5-3....

Specifying Availability Requirements

You should encourage your customers to specify availability requirements with precision. Consider the difference between an uptime of 99.70 percent and an uptime of 99.95 percent. An uptime of 99.70 percent means the network is down 30 minutes per week, which is not acceptable to many customers. An uptime of 99.95 percent means the network is down 5 minutes per week, which may be acceptable, depending on the type of business. Availability requirements should be specified with at least two...

Making Network Design Tradeoffs

Despite what politicians tell us about state and federal budgets during an election year, in the real world meeting goals requires making tradeoffs. This section describes some typical network design tradeoffs. To meet high expectations for availability, redundant components are often necessary, which raises the cost of a network implementation. To meet rigorous performance requirements, high-cost circuits and equipment are required. To enforce strict security policies, expensive monitoring...

Cable Modem Remote Access

Another option for remote access is a cable modem. A cable modem operates over the coax cable that is used by cable TV (CATV) providers. Coax cable supports higher speeds than telephone lines, so cable-modem solutions are much faster than analogmodem solutions, and usually faster than ISDN solutions (depending on how many users share the cable). Another benefit of cable modems is that no dialup is required. This is an advantage over analog modems that take a long time to dial and connect to a...

Developing a Baseline of Network Performance

Developing an accurate baseline of a network's performance is not an easy task. One challenging aspect is selecting a time to do the analysis. It is important that you allocate a lot of time (multiple days) if you want the baseline to be accurate. If measurements are made over too short a timeframe, temporary errors appear more significant than they are. In addition to allocating sufficient time for a baseline analysis, it is also important to find a typical time period to do the analysis. A...

Tools for Developing Network Maps

Simple Network Diagram From Dmarcation

Many customers can't provide detailed and up-to-date maps of the existing network. In many cases, you need to develop the maps yourself. Companies that are constantly working in fire-fighting mode don't have time to proactively document the existing network. To develop a network drawing, you should invest in a good network-diagramming tool. You can use Cisco Works to map a network and collect other types of network audit information, including hardware and software versions, configurations, and...

Characterizing Types of Traffic Flow for New Network Applications

As mentioned, a network flow can be characterized by its direction and symmetry. Direction specifies whether data travels in both directions or in just one direction. Direction also specifies the path that a flow takes as it travels from source to destination through an internetwork. Symmetry describes whether the flow tends to have higher performance or QoS requirements in one direction than the other direction. Many network applications have different requirements in each direction. Some data...

Optimum Network Utilization

Network utilization is a measurement of how much bandwidth is used during a specific time period. Utilization is commonly specified as a percentage of capacity. For example, a network-monitoring tool might state that network utilization on an Ethernet segment is 30 percent, meaning that 30 percent of the capacity is in use. Network analysis tools use varying methods for measuring bandwidth usage and averaging the usage over elapsed time. Usage can be averaged every millisecond, every second,...

About the Technical Reviewers

Birkner, CCIE No. 3719, is a Technical Advisor at Cisco Systems, where he specializes in IP, MPLS, and QoS network design. He has influenced many large carrier and enterprise network designs worldwide. Matt has spoken on MPLS at the United States and EMEA Cisco Networkers over the past few years. Matt, a double CCIE, wrote the Cisco Press book Cisco Internetwork Design. Matt holds a bachelor's of science in electrical engineering from Tufts University. Blair Buchanan, CCIE No. 1427,...

Broadcast Multicast Behavior

A broadcast frame is a frame that goes to all network stations on a LAN. At the data link layer, the destination address of a broadcast frame is FF FF FF FF FF FF (all 1s in binary). A multicast frame is a frame that goes to a subset of stations. For example, a frame destined to 01 00 0C CC CC CC goes to Cisco routers and switches that are running the Cisco Discovery Protocol (CDP) on a LAN. Layer 2 internetworking devices, such as switches and bridges, forward broadcast and multicast frames...

Testing Methods Used

A short test plan was written that documents the test objectives, acceptance criteria, testing equipment, and planned testing steps. NetPredict's NetPredictor tool was selected as the primary testing tool because it was able to meet the distinct objectives of measuring existing network performance and predicting performance when the new Oracle order-entry application is added. A model of traffic load on the networks at Umqua was derived by talking to Umqua's network managers. The model was...

The WAN Design for Klamath Paper Products

A decision table was used as part of the design process for Klamath. Klamath's major goals were consolidated and critical goals were placed at the top of the table, as shown in Table 11-7. Potential options were placed in the leftmost column and evaluated on whether they met a critical goal. Table 11-7. WAN Technologies Decision Table Table 11-7. WAN Technologies Decision Table Critical Goals for the WAN Technology Must use currently available technologies from WAN service providers in the...