Methods of Assigning IP Addresses

This section discusses methods of assigning IP addresses to end systems and explains their influence on administrative overhead. Address assignment includes assigning an IP address, a default gateway, one or more domain name servers that resolve names to IP addresses, time servers, and so forth. Before selecting the desired IP address assignment method, the following questions should be answered How many devices need an IP address Which devices require static IP address assignment Is IP address...

TCPIP Transport Layer Protocols

The TCP IP transport layer includes the following two protocols Transmission Control Protocol (TCP) Provides connection-oriented, end-to-end reliable transmission. Before sending any data, TCP on the source device establishes a connection with TCP on the destination device, ensuring that both sides are synchronized. Data is acknowledged any data not received properly is retransmitted. FTP is an example of an application that uses TCP to guarantee that the data sent from one device to another is...

Core Layer Functionality

This section describes core layer functions and the interaction of the core layer with the distribution layer. The function of the core layer is to provide fast and efficient data transport. Characteristics of the The core layer is a high-speed backbone that should be designed to switch packets as quickly as possible to optimize communication transport within the network. Because the core is critical for connectivity, core layer devices are expected to provide a high level of availability and...

The Cisco Service Oriented Network Architecture

The extremely rich variety of application-level business solutions available today and the need to integrate these applications drives the need for a new network architecture. This section introduces the Cisco vision and framework that enable customers to build a more intelligent network infrastructure. the Cisco SONA architectural framework shifts the view of the network from a pure traffic transport-oriented view toward a service- and application-oriented view. Business Drivers for a New...

IP Extended Access Lists

Standard access lists offer quick configuration and low overhead in limiting traffic based on source addresses in a network. Extended access lists provide a higher degree of control by enabling filtering based on the source and destination addresses, transport layer protocol, and application port number. These features make it possible to limit traffic based on the uses of the network. As shown in Figure B-14, every condition tested in a line of an extended access list must match for the line...

What Is a Routing Metric

A metric is a value (such as path length) that routing protocols use to measure paths to a destination. Different routing protocols base their metric on different measurements, including hop count, interface speed, or more-complex metrics. Most routing protocols maintain databases containing all the networks that the routing protocol recognizes and all the paths to each network. If a routing protocol recognizes more than one way to reach a network, it compares the metric for each different path...

Route Summarization

Chapter 6 explains route summarization (which is also called route aggregation or supernetting). In route summarization, a single summary address in the routing table represents a set of routes. Summarization reduces the routing update traffic, the number of routes in the routing table, and the overall router overhead in the router receiving the routes. A large flat network is not scalable because routing traffic consumes considerable network resources. When a network change occurs, it is...

Cisco IP Communications Return on Investment Calculator

The Cisco IP Communications (IPC) Return on Investment (ROI) calculator can be useful for analyzing IP telephony requirements and estimating the cost savings a customer will experience when migrating to IP telephony. The IPC ROI calculator is available at http www.cisco.com NOTE You must have a Cisco partner account to access this tool.

Distribution Layer Functionality

This section describes distribution layer functions and the interaction of the distribution layer with the core and access layers. The distribution layer represents both a separation between the access and core layers and a connection point between the diverse access sites and the core layer. The distribution layer determines department or workgroup access and provides policy-based connectivity. Following are the characteristics of the distribution layer Distribution layer devices control...

Case Study ACMC Hospital IP Addressing Design

This case study is a continuation of the ACMC Hospital case study introduced in Chapter 2, Applying a Methodology to Network Design. Use the scenarios, information, and parameters provided at each task of the ongoing case study. If you encounter ambiguities, make reasonable assumptions and proceed. For all tasks, use the initial customer scenario and build on the solutions provided thus far. You can use any and all documentation, books, white papers, and so on. In each step, you act as a...

Designing Route Redundancy

To minimize the effect of link failures To minimize the effect of an internetworking device failure Redundant routes might also be used for load balancing when all routes are up. By default, the Cisco IOS balances between a maximum of four equal-cost paths for IP. Using the maximum-paths maximum-path router configuration command, you can request that up to 16 equally good routes be kept in the routing table (set maximum-path to 1 to disable load balancing). When a packet is process-switched,...

Case Study Answers

The following table summarizes ACMC's requirements. Higher campus speeds, at least Gigabit Ethernet core IPsec virtual private network for teleworkers Although this is not a stated requirement, it would be useful and is common in today's networks Designated server farm, improved data center area To allow for future delay-sensitive applications (such as IP telephony) without replacing network equipment 2. The following table summarizes information missing from the scenario and the related...

Configure

Cisco Catalyst 6506E, WS-SUP32-GE-3B, Fan Tray req. P S) To add options, select item category on the left, then select options from the list displayed on the right. Use the Cisco OS Software Selector for software selection assistance. E3 Software Options license Options S Module Option 1 (included Supervisor) 0 Module Option 2 B WS-X614& FE-SFP 0WS-X651GA-GBIC SWS-X651S-GE-TX B WS-X6524-100FX-MM B WS-X654-B-RJ-21 0 WS-X6640-RJ45 SWS-X6704-10GE B WS-X67O0-1O& 3C S WS-X670B-10G-3CXL 0...

Case Study Scenario

This case study analyzes the network infrastructure of ACMC Hospital, a fictitious small county hospital. The hospital has provided you with a short description of the current situation and its plans. As a network designer, it is your job to identify all the organization's requirements and data that will allow you to provide an effective solution. ACMC Hospital is a medium-sized regional hospital located in Acme County, with approximately 500 staff members supporting up to 1000 patients. The...

Risk Assessment and Management

Network security employs risk management to reduce risk to acceptable levels. It is important to note that risks are not eliminated by network security they are reduced to levels acceptable to the organization. An organization defines an acceptable level of risk based on such factors as the following The value of the organization's data The expectation of loss in the event of compromise The severity and probability of risks The weighting of these factors is called risk assessment, which is a...

Answers to Review Questions

Static routing might be preferred over dynamic routing in the following situations For slow links, such as dialup links When the administrator needs control over the routes used For a backup to a dynamically learned route 2. Dynamic routing protocols do the following Find sources from which routing information can be received (usually neighboring routers) Select best paths toward all reachable destinations, based on received information Maintain this routing information Have a means of...

Case Study Questions

Step 1 Hospital Omega is a nearby hospital that has been having financial difficulties. It is facing large licensing and application development costs to bring its financial and other applications up to date. To cut costs and stabilize finances, Hospital Omega will merge with ACMC. All data services will move to the ACMC data center and gradually migrate to the modern applications that ACMC already has in place. The Hospital Omega network was deployed between seven and ten years ago, and in...

External and Internal BGP

Any two routers that have formed a TCP connection to exchange BGP routing information in other words, a BGP connection are called peers or neighbors. BGP peers can be either internal or external to the AS. When BGP is running between routers within one AS, it is called internal BGP (IBGP). IBGP is run within an AS to exchange BGP information so that all internal BGP speakers have the same BGP routing information about outside autonomous systems, and so that this...

Syslog Accounting

A system message and error reporting service is an essential component of any operating system. The syslog system message service provides a means for the system and its running processes to report system state information to a network manager. Cisco devices produce syslog messages as a result of network events. Every syslog message contains a time stamp (if enabled), severity level, and facility. Example 3-1 shows samples of syslog messages produced by the Cisco IOS software. The most common...

Static and Dynamic IPv6 Name Resolution

IPv6 and IPv4 name resolutions are similar. The following two name resolutions are available with IPv6 Static name resolution Accomplished by manual entries in the host's local configuration files. Dynamic name resolution Accomplished using a DNS server that supports IPv6, usually along with IPv4 support. As shown in Figure 6-22, an IPv6-aware application requests the destination hostname's IPv6 address from the DNS server using a request for an A6 record an A6 record is a new DNS feature that...

Cisco IOS Software Packaging

Cisco is migrating to using Cisco IOS Packaging to simplify the image-selection process by consolidating the total number of packages and using consistent package names across all hardware products. Figure 5-22 illustrates the various packages available with Cisco IOS packaging. Figure 5-21 Cisco IOS Software in the Network Figure 5-21 Cisco IOS Software in the Network Broadband access Mobility and wireless Data center Security Broadband access Mobility and wireless Data center Security Cisco...

The Internet as a WAN Backup Technology

This section describes the Internet as an alternative option for a failed WAN connection. This type of connection is considered best-effort and does not guarantee any bandwidth. Common methods for connecting noncontiguous private networks over a public IP network include the following IP routing without constraints The following sections describe these methods. When relying on the Internet to provide a backup for branch offices, a company must fully cooperate with the ISP and announce its...

Translation Transition Mechanism

Dual-stack and tunneling techniques manage the interconnection of IPv6 domains. For legacy equipment that will not be upgraded to IPv6 and for some deployment scenarios, techniques are available for connecting IPv4-only nodes to IPv6-only nodes, using translation, an extension of NAT techniques. As shown in Figure 6-26, an IPv6 node behind a translation device has full connectivity to other IPv6 nodes and uses NAT functionality to communicate with IPv4 devices. Translation techniques are...

Review Questions

Answer the following questions, and then refer to Appendix A for the answers. 1. What features are included in the Cisco vision of an intelligent network 2. Describe the three phases of evolving to an intelligent information network. 3. Describe the three layers of the SONA framework. 4. Name some of the benefits of using the SONA framework. 5. Match the PPDIOO network lifecycle phases with their correct descriptions. Phases 2. A network design specification is produced 3. Includes fault...

Design Considerations for Outdoor Wireless Networks

Traditional outdoor wireless deployment options include point-to-point or point-to-multipoint bridging between buildings. Outdoor wireless mesh is a relatively new option in which the APs are connected in a mesh with many redundant connections between nodes. Figure 9-33 illustrates these options. Figure 9-33 Outdoor Wireless Options Figure 9-33 Outdoor Wireless Options Mesh APs discover each other automatically and select the best path through the mesh for maximizing system capacity and...

WAN Transport Technology Pricing and Contract Considerations

This section discusses pricing and contract considerations for WAN technologies. NOTE The pricing, time frame, and contract details provided here are examples from the United States market. Organizations in other countries might have different experiences. However, the items in this section should be considered when implementing a WAN. Service and pricing options between carriers should be compared and negotiated, depending on competition in the area. Historically, WAN transport costs include...

Decision Tables in Network Design

Decision tables are used for making systematic decisions when there are multiple solutions or options to a network issue or problem. Decision tables facilitate the selection of the most appropriate option from many possibilities and can be helpful for justifying why a certain solution was chosen. Options are usually selected based on the highest level of compliance with given requirements. Basic guidelines for creating a network design decision table include the following Step 1 Determine the...

Routing in the Campus Core

The Campus Core provides high-speed data transmission between Building Distribution devices. The Campus Core is critical for connectivity and, therefore, incorporates a high level of redundancy using redundant links and load sharing between equal-cost paths. In the event of a link failure, it must immediately converge, adapting quickly to change to provide a seamless transport service. EIGRP and OSPF both adapt quickly to changes and have short convergence times. Therefore, they are suitable...

Traditional WAN Technologies

Traditional WAN technologies include the following Leased lines Point-to-point connections indefinitely reserved for transmissions, rather than used only when transmission is required. The carrier establishes the connection either by dedicating a physical wire or by delegating a channel using frequency division multiplexing or time-division multiplexing (TDM). Leased-line connections usually use synchronous transmission. Circuit-switched networks A type of network that, for the duration of the...

Local Loops Trunks and Interswitch Communications

Figure 8-5 illustrates a typical telephone infrastructure and connections between telephony devices. Figure 8-5 Local Loops, Trunks, and Interswitch Communication Figure 8-5 Local Loops, Trunks, and Interswitch Communication The telephone infrastructure starts with a simple pair of copper wires running to the end user's home or business. This physical cabling is known as a local loop or telephone line the local loop physically connects the home telephone to the CO PSTN switch. Similarly, the...

Threat Reconnaissance Attacks

Reconnaissance attacks aim to discover information about a network, including the following Network services that are running A common technique to find active targets such as networking devices and user endpoints is port scanning, in which data is sent to various TCP and User Datagram Protocol (UDP) ports on a device and the response from the device is evaluated. To avoid reconnaissance attacks, a network should be tested to see how much it would reveal if attacked. The following are some...

Determining the Size of the Network

The first step in designing an IP addressing plan is determining the size of the network to establish how many IP subnets and how many IP addresses are needed on each subnet. To gather this information, answer the following questions How many locations does the network consist of The designer must determine the number and type of locations. How many devices in each location need addresses The network designer must determine the number of devices that need to be addressed, including end systems,...

Route Redistribution Direction

Redistribution is often applied between the Campus Core and Enterprise Edge protocols. As shown in Figure 7-16, redistribution is possible in two ways One-way route redistribution Routing information is redistributed from one routing protocol or domain to another, but not vice versa. Static or default routes are required in the opposite direction to provide connectivity. Two-way route redistribution Routing information is redistributed from one routing protocol or domain to another, and vice...

Enterprise Data Center Infrastructure

Figure 4-22 shows a typical large Enterprise Data Center infrastructure design. The design follows the Cisco multilayer infrastructure architecture, including core, aggregation, and access layers. NOTE In the Enterprise Data Center, the distribution layer is known as the aggregation layer. Figure 4-22 Sample Data Center Infrastructure Figure 4-22 Sample Data Center Infrastructure Layer 2 Clustering Blade Chassis Blade Chassis Mainframe Layer 3 and NIC Teaming with Pass-Through with Integrated...

Analog and Digital Signaling

The human voice generates sound waves a telephone converts the sound waves into analog signals. However, analog transmission is not particularly efficient. Analog signals must be amplified when they become weak from transmission loss as they travel. However, amplification of analog signals also amplifies noise. The PSTN is a collection of interconnected voice-oriented public telephone networks, both commercial and government-owned. The PSTN today consists almost entirely of digital technology,...

Design Considerations for Campus Wireless Networks

This section reviews design considerations for enterprise campus wireless networks. To develop an enterprise campus wireless network design, the following questions need to be answered How many APs are needed Sufficient APs to provide RF coverage, with the required features to support the wireless clients, are needed. Different APs have different features, including internal or external antenna, single or dual radios, and number of devices supported. Optimally, deploy more APs than indicated by...

Cisco SONA Framework

As illustrated in Figure 3-8, the Cisco SONA provides an enterprise-wide framework that integrates the entire network campus, data center, enterprise edge, WAN, branches, and teleworkers offering staff secure access to the tools, processes, and services they require. Advanced Analytics and Decision Support Advanced Analytics and Decision Support The modules of the Cisco Enterprise Architecture represent focused views of each of the places in the network described in the SONA framework. Each...

QoS for Voice

IP telephony places strict requirements on IP packet loss, packet delay, and delay variation (jitter). Therefore, QoS mechanisms on Cisco switches and routers are important throughout the network if voice traffic is sharing network resources with data traffic. Redundant devices and network links that provide quick convergence after network failures or topology changes are also important to ensure a highly available infrastructure. The following summarizes the process to determine whether to...

Case Study 101 Answers

As mentioned in Chapter 2, a key business security requirement is that the hospital must comply with the U.S. Health Insurance Portability and Accountability Act (HIPAA). HIPAA is about patient confidentiality and the costs of failing to provide adequate security and confidentiality. Threats to network security include the following Reconnaissance, usually the prelude to a more focused attack Gaining unauthorized system access DoS, including from worms, viruses, and patch management issues...

Warning and Disclaimer

This book is designed to provide information about designing Cisco networks. Every effort has been made to make this book as complete and as accurate as possible, but no warranty or fitness is implied. The information is provided on an as is basis. The author, Cisco Press, and Cisco Systems, Inc. shall have neither liability nor responsibility to any person or entity with respect to any loss or damages arising from the information contained in this book or from the use of the discs or programs...

Enterprise Campus Modules

This section introduces the Enterprise Campus functional area and describes the purpose of each module therein. It also discusses connections with other modules. An enterprise campus site is a large site that is often the corporate headquarters or a major office. Regional offices, SOHOs, and mobile workers might have to connect to the central campus for data and information. As illustrated in Figure 3-11, the Enterprise Campus functional area includes the Campus Infrastructure module and,...

Characterizing the Existing Network and Sites

The second step of the design methodology is characterizing the existing network and sites. Information collected and documented in this step is important, because the design might depend on the existing network's hardware, software, and link capacity. In many cases, a network already exists and the new design relies on restructuring and upgrading the existing network and sites. Even when a network does not exist, the sites that will be networked still should be examined. The following sections...

Maintaining Data Integrity

Cryptography also provides data integrity mechanisms to protect data in transit over untrusted networks. Cryptographic protocols, such as secure fingerprints and digital signatures, can detect any integrity violation of sensitive data. Secure fingerprints attach a cryptographically strong checksum to data. This checksum is generated and verified using a secret key that only authorized subjects know. By verifying the checksum of received data, an authorized subject can verify data integrity. For...

Enterprise Teleworker Branch of One Design

Organizations are constantly striving to reduce costs, improve employee productivity, and retain valued employees. These goals can be furthered by allowing employees to work from home with quality, function, performance, convenience, and security similar to that available in the office. With a work environment in the residence, employees can optimally manage their work schedules, allowing for higher productivity (less affected by office distractions) and greater job satisfaction (flexibility in...

Virtual LANs

As noted earlier, a broadcast domain includes all devices that receive each others' broadcasts (and multicasts). All the devices connected to one router port are in the same broadcast domain. Routers block broadcasts (destined for all networks) and multicasts by default routers forward only unicast packets (destined for a specific device) and packets of a special type called directed broadcasts. Typically, you think of a broadcast domain as being a physical wire, a LAN. But a broadcast domain...

The Cisco UWN Architecture

In a traditional WLAN, each AP operates as a separate autonomous node configured with SSID, RF channel, RF power settings, and so forth. Scaling to large contiguous, coordinated WLANs and adding higher-level applications is challenging with these autonomous APs. For example, if an autonomous AP hears a nearby AP operating on the same channel, the autonomous AP has no way of determining whether the adjacent AP is part of the same network or a neighboring network. Some form of centralized...

Cisco Enterprise MAN and WAN Architecture Technologies

The Cisco Enterprise MAN and WAN architecture employs a number of MAN and WAN technologies engineered and optimized to interoperate as a contiguous system, providing the integrated QoS, network security, reliability, and manageability required to support a variety of advanced business applications and services. These technologies include a number of secure alternatives to traditional private WAN connectivity and help increase network scalability and reduce monthly carrier fees. The Cisco...

Campus Core Design Considerations

Low price per port and high port density can govern switch choice for wiring closet environments, but high-performance wire-rate multilayer switching drives the Campus Core design. Using Campus Core switches reduces the number of connections between the Building Distribution layer switches and simplifies the integration of the Server Farm module and Enterprise Edge modules. Campus Core switches are primarily focused on wire-speed forwarding on all interfaces and are differentiated by the level...

Functional Areas of the Cisco Enterprise Architecture

At the first layer of modularity in the Cisco Enterprise Architecture, the entire network is divided into functional components functional areas that contain network modules while still maintaining the hierarchical concept of the core-distribution-access layers within the network modules as needed. NOTE The access, distribution, and core layers can appear in any functional area or module of the Cisco Enterprise Architecture. The Cisco Enterprise Architecture comprises the following six major...

Voice Coding and Compression

Voice communication over IP relies on voice that is coded and encapsulated into IP packets. This section provides an overview of the various codecs used in voice networks. NOTE The term codec can have the following two meanings A coder-decoder An integrated circuit device that typically uses PCM to transform analog signals into a digital bit stream and digital signals back into analog signals. A software algorithm Used to compress and decompress speech or audio signals in VoIP, Frame Relay, and...

Optimizing Bandwidth in a WAN

It is expensive to transmit data over a WAN. Therefore, one of many different techniques such as data compression, bandwidth combination, tuning window size, congestion management (queuing and scheduling), congestion avoidance, and traffic shaping and policing can be used to optimize bandwidth usage and improve overall performance. The following sections describe these techniques. Compression is the reduction of data size to save transmission time. Compression enables more efficient use of the...

Lightweight APs

The available Cisco lightweight APs and their features are detailed in Table 9-6. Table 9-6 Cisco Lightweight AP Features Table 9-6 Cisco Lightweight AP Features (Continued) 1 Remote edge AP (REAP) and hybrid REAP (H-REAP) are described in the Design Considerations for Branch Office Wireless Networks section later in this chapter. AP models with the most memory support the most feature flexibility. NOTE The AP features supported might change as products are updated, products are replaced, and...

Enterprise Branch Module

The Enterprise Branch module extends the enterprise by providing each location with a resilient network architecture with integrated security, Cisco Unified Communications, and wireless mobility. A branch office generally accommodates employees who have a compelling reason to be located away from the central site, such as a regional sales office. A branch office is sometimes called a remote site, remote office, or sales office. Branch office users must be able to connect to the central site to...

RF Site Survey

This section reviews the reasons that an RF site survey is used in wireless network design, and the process to conduct such a survey. An RF site survey is the first step in the design and deployment of a wireless network, and the most important step to ensure desired operation. A site survey is a process by which the surveyor studies the facility to understand the RF characteristics in the environment, plans and reviews RF coverage areas, checks for RF interference, and determines the...

Identifying Customer Requirements

As the organization's network grows, so does the organization's dependency on the network and the applications that use it. Network-accessible organizational data and mission-critical applications that are essential to the organization's operations depend on network availability. To design a network that meets customers' needs, the organizational goals, organizational constraints, technical goals, and technical constraints must be identified. This section describes the process of determining...

Infrastructure Device Characteristics and Considerations

Network end-user devices are commonly connected using switched technology rather than using a shared media segment. Switched technology provides dedicated network bandwidth for each device on the network. Switched networks can support network infrastructure services, such as QoS, security, and management a shared media segment cannot support these features. In the past, LAN switches were Layer 2-only devices. Data link layer (Layer 2) switching supports multiple simultaneous frame flows....

Call Control and Transport Protocols

Voice communication over IP is a mix of call control signals and voice conversations coded and possibly compressed into IP packets. Both reliable (connection-oriented) and so-called unreliable (connectionless) transmissions are required for voice communication. Reliable transmission guarantees sequenced, error-free, flow-controlled transmission of packets. However, because reliable transport is connection-oriented, it can delay transmission and reduce throughput. TCP provides reliable transport...

Environmental Characteristics and Considerations

The campus environment, including the location of the network nodes, the distance between the nodes, and the transmission media used, influences the network topology. This section examines these considerations. The location of Enterprise Campus nodes and the distances between them determine the network's geography. Nodes, including end-user workstations and servers, can be located in one or multiple buildings. Based on the location of nodes and the distance between them, the network designer...

High Availability in the Server Farm

Improving the reliability of critical workstations and servers usually depends on the hardware and operating system software in use. Some common ways of connecting include the following Single attachment When a workstation or server has traffic to send to a station that is not local, it must know the address of a router on its network segment. If that router fails, the workstation or server needs a mechanism to discover an alternative router. If the workstation or server has a single...

WAN Transport Technologies

Dwdm Concentrator

Table 5-1 compares various WAN technologies, based on the main factors that influence technology selection. This table provides typical baseline characteristics to help you compare the performance and features offered by different technologies. Often, the offerings of the service provider limit your technology decisions. NOTE Some WAN technology characteristics differ between service providers Table 5-1 is meant to illustrate typical characteristics. Table 5-1 WAN Transport Technology...

Enterprise Edge Modules

Internet Vpn Ecommerce

This section describes the components of the Enterprise Edge and explains the importance of each module. The Enterprise Edge infrastructure modules aggregate the connectivity from the various elements outside the campus using various services and WAN technologies as needed, typically provisioned from service providers and route the traffic into the Campus Core layer. The Enterprise Edge modules perform security functions when enterprise resources connect across public networks and the Internet....

Case Study ACMC Hospital Modularity

Modularity Diagram Hospital

This case study is a continuation of the ACMC Hospital case study introduced in Chapter 2. Use the scenarios, information, and parameters provided at each task of the ongoing case study. If you encounter ambiguities, make reasonable assumptions and proceed. For all tasks, use the initial customer scenario and build on the solutions provided thus far. You can use any and all documentation, books, white papers, and so on. In each step, you act as a network design consultant. Make creative...

Communication Among OSI Layers

This section describes how communication among the seven OSI layers is accomplished. When you send an e-mail from Toronto to your friend in San Francisco, you can think of your e-mail application sending a message to the e-mail application on your friend's computer. In OSI model terms, information is exchanged between peer OSI layers the application layer on your computer is communicating with the application layer on your friend's computer. However, to accomplish this, the e-mail must go...

Tools for Analyzing Traffic

Tools used for traffic analysis range from manual identification of applications using Cisco IOS software commands to those in which dedicated software- or hardware-based analyzers capture live packets or use the Simple Network Management Protocol (SNMP) to gather interface information. Analysis tools include the following Cisco IOS Network-Based Application Recognition (NBAR) NBAR can be used to identify the presence of well-known applications and protocols in the network. Cisco IOS NetFlow...

Network Application Characteristics and Considerations

The network application's characteristics and requirements influence the design in many ways. The applications that are critical to the organization, and the network demands of these applications, determine enterprise traffic patterns inside the Enterprise Campus network, which influences bandwidth usage, response times, and the selection of the transmission medium. Different types of application communication result in varying network demands. The following sections review four types of...

Acronyms and Abbreviations

This element lists abbreviations, acronyms, and initialisms used in this book and in the internetworking industry. Many of these acronyms and other terms are also described in the Cisco Internetworking Terms and Acronyms resource, available at http www.cisco.com univercd cc td doc cisintwk ita . Authentication, authorization, and accounting Algebraic code-excited linear prediction Application and Content Networking System Adaptive Differential Pulse Code Modulation American National Standards...

WLAN Controllers

Despite being called a wireless LAN controller, a WLC is connected to the wired LAN and to the lightweight APs by wires. The WLC does not have any wireless connections. The following are three important WLC terms Ports A WLC port is a physical connection on the WLC that connects to its neighboring switch in the wired campus infrastructure. Each WLC port is by default an 802.1Q VLAN trunk port the WLC forwards information received from the WLANs, via the APs, over a trunk port to the campus...

Radio Resource Management and RF Groups

This section provides a brief overview of Cisco RRM and RF groups. Real-time RF management is a foundation of the Cisco UWN solution. Key RF challenges in managing a wireless environment include the following Limited nonoverlapping channels The physical characteristics of RF propagation The transient nature of RF environments AP capacity is affected by the applications being run over the wireless network. For example, a recommended practice is to support approximately seven to eight voice calls...

Comprehensive Example

This section presents a comprehensive example, tying together many of the concepts covered in the rest of this chapter. Figure 1-24 illustrates the network used in this example. Figure 1-24 PC1 in New York Is Sending FTP Data to FS1 in London Figure 1-24 PC1 in New York Is Sending FTP Data to FS1 in London In this network, PC1, located in New York, has an FTP connection with the file server FS1 in London. PC1 is transferring a file, using FTP, to FS1. The path between PC1 and FS1 goes through...

Voice Quality Issues

Overall voice quality is a function of many factors, including delay, jitter, packet loss, and echo. This section discusses these factors and ways to minimize them. Packet delay can cause voice quality degradation. When designing networks that transport voice, you must understand and account for the network's delay components. Correctly accounting for all potential delays ensures that overall network performance is acceptable. The generally accepted limit for good quality voice connection delay...

Info

Integrated System for Terminal to Mainframe Connectivity (VTAM) Connect Multivendor Devices (Packets) Pervasive, Open Networks Enable Client Server to Extend Beyond Corporate Boundaries (TCP IP) Organizations are finding that networking is no longer just about connectivity rather, network intelligence is starting to play a role in improving business performance and processes. Intelligence enhances the network's role as a foundation for enabling communication, collaboration, and business...

Bandwidth Considerations

Bandwidth availability is a key issue to consider when designing voice on IP networks. The amount of bandwidth per call varies greatly, depending on which codec is used and how many voice samples are required per packet. However, the best coding mechanism does not necessarily result in the best voice quality for example, the better the compression, the worse the voice quality. The designer must decide which is more important better voice quality or more efficient bandwidth consumption. Reducing...

Introduction to IP Telephony

IP telephony refers to cost-effective communication services, including voice, fax, and voice-messaging applications, transported via the packet-switched IP network rather than the circuit-switched PSTN. VoIP uses voice-enabled routers to convert voice into IP packets and route those packets between corresponding locations. Users do not often notice the implementation of VoIP in the network they use their traditional phones, connected to a PBX. However, the PBX is not connected to the PSTN or...

Building Access Layer Design Considerations

When implementing the campus infrastructure's Building Access layer, consider the following questions How many users or host ports are currently required in the wiring closet, and how many will it require in the future Should the switches be fixed or modular configuration How many ports are available for end-user connectivity at the walls of the buildings How many access switches are not located in wiring closets What cabling is currently available in the wiring closet, and what cabling options...

Case Study 102 Answers

The flat Layer 2 network is one issue. Some stability could be added to the network with Layer 3 switching. The hospital does not use DHCP adding it could be a time-consuming but worthwhile process. Another issue is the hospital's older equipment, which should be modernized. The old cabling is another issue that needs to be addressed. Random testing of 10 to 20 percent of the cabling should be conducted to get a feel for its condition. If the cabling is substandard, the hospital will need to be...

Physical Addresses

MAC addresses were discussed earlier recall that these are at the data link layer and are considered physical addresses. When a network interface card is manufactured, it is assigned an address called a burned-in address (BIA) that doesn't change when the network card is installed in a device and is moved from one network to another. Typically, this BIA is copied to interface memory and is used as the interface's MAC address. MAC addresses are analogous to Social Insurance numbers or Social...

Design Considerations for Branch Office Wireless Networks

This section reviews design considerations for branch wireless network design, including REAP and H-REAP. The following are several key design considerations for branch office wireless networks How many APs are needed, and what are their requirements Recall that, generally, an AP can support 7 to 8 wireless phones or 20 or more data-only devices. Ports must be available on the local switch to connect the APs to the wired network. Power to the APs, either through PoE or traditional power...

Enterprise Branch Design

Branch Office Network Design

Requirements differ with the size of the branch offices. Consider to the following questions when How many branch locations need to be supported How many existing devices (including end users, hosts, and network infrastructure) are to be supported at each location The number of devices supported is limited by the physical number of ports available. How much growth is expected at each location, and therefore what level of scalability is required What are the high availability requirements at...

PSTN Numbering Plans

PSTN numbering plans are the foundation for routing voice calls through the PSTN network. For any telephone network to function, a unique address must identify each telephone. Voice addressing relies on a combination of international and national standards, local telephone company practices, and internal customer-specific codes. The International Telecommunications Union Telecommunication Standardization Sector (ITU-T) recommendation E.164 defines the international numbering plan. Each...

PBXs and the PSTN

Pstn Network

This section introduces PBX and PSTN switches and networks. Differences Between a PBX and a PSTN Switch As shown in Table 8-1, PBXs and PSTN switches share many similarities, but they also have many differences. Table 8-1 PBX and PSTN Switch Comparison Table 8-1 PBX and PSTN Switch Comparison Scales to hundreds of thousands of phones Uses proprietary protocols to control telephones Uses open-standard protocols between switches and telephones Interconnects remote branch subsystems and telephones...

Controller Redundancy Design

Recall that the AP discovery and join decision process first looks for a defined primary, secondary, or tertiary WLC (as specified by the controller's sysName). An AP's second choice is to join a WLC configured as a master controller. This is typically used only on initial AP deployment to find an initial controller, at which time the AP should be configured with its deterministic controllers. The last choice in the AP join decision algorithm is to try to dynamically choose a WLC based on the...

Building Distribution Layer Design Considerations

The Building Distribution layer aggregates the Building Access layer, segments workgroups, and isolates segments from failures and broadcast storms. This layer implements many policies based on access lists and QoS settings. The Building Distribution layer can protect the Campus Core network from any impact of Building Access layer problems by implementing all the organization's policies. When implementing the Building Distribution layer, consider the following questions How many devices will...

Telephony Signaling

In a telephony system, a signaling mechanism is required for establishing and disconnecting The following forms of signaling are used when a telephone call is placed via a PBX Between the telephone and PBX Between the PBX and PSTN switch At a high level, there are two signaling realms, as shown in Figure 8-7 Local-loop signaling Between a PSTN or PBX switch and a subscriber (telephone) Trunk signaling Between PSTN switches, between a PSTN switch and a PBX, or between PBX switches Figure 8-7...

Case Study ACMC Hospital UWN Considerations

This case study is a continuation of the ACMC Hospital case study introduced in Chapter 2, Applying a Methodology to Network Design. Use the scenarios, information, and parameters provided at each task of the ongoing case study. If you encounter ambiguities, make reasonable assumptions and proceed. For all tasks, use the initial customer scenario and build on the solutions provided thus far. You can use all documentation, books, white papers, and so on. In each step, you act as a network design...