In Chapter 4 of this book, we proposed a plan for uniting the three independent and diverse networks of the fictitious company, Terra Flora. One of the company's main goals was to centralize all administration.
Note Terra Flora is a totally fictitious corporation. The names of companies, products, people, characters, and data mentioned herein are fictitious and are in no way intended to represent any real individual, company, product, or event, unless otherwise noted.
Terra Flora elected to use Bay Networks products, which combine a distributed management support foundation with SNMP-based tools for comprehensive router configuration, monitoring, and control. They will implement the Bay Networks Switched Internetworking Service (BaySIS) architecture. This extensible switched internetworking architecture is comprised of four basic services¾transport, policy, operation, and design¾which are implemented across the enterprise network. In this way, Terra Flora will integrate multiprotocol routing, switching, and shared-media and wide-area solutions into a cohesive, switched topology, all managed by a single network management system.
The Bay Networks Access Stack Note (ASN) router has a stackable architecture. Up to four ASN units are supported in one stack. An ASN stack supports up to 40 network interfaces and 200,000 pps forwarding performance, providing a superior path for growth. The MC68040 processor in the ASN's integrated design maintains high forwarding and filtering rates, regardless of the number of protocols and network interfaces used, even when processing Simple Network Management Protocol (SNMP) management inquiries.
The ASN meets the connectivity needs of the Terra Flora remote branch offices by offering modularity and flexibility for building configurations. The ASN provides network connectivity through a selection of net modules and adapter modules. An ASN can support up to four net modules, such as 100BASE-T, 10BASE-T Ethernet, 4/16 Mbps Token Ring, FDDI, Synchronous, and ISDN BRI, to meet a wide variety of connectivity requirements. Wide-area services, such as PPP, X.25, Frame Relay, SMDS, HDLC encapsulation, and ATM DXI, are supported by the ASN synchronous interface.
The method used to accomplish this consolidation of resources and information is described next.
The following diagram of the network shows the NENTS40B0FO1, NENTS40DIV01, NENTS40ENT01, EUNTS4ENT01, and EUNTS40DIV01 servers running multi-provider router (MPR) software. MPR passes requests to the various network providers configured in the system. These servers are connected to a Bay Networks Backbone Link Node (BLN) router through T1 links.
Figure F.3 Remote Enterprise Multi-provider Routing
The BLN creates a multi-protocol, collapsed, WAN backbone that provides a centralized wide-area infrastructure. The BLN is also connected to another BLN over a T3 link which is attached to two Bay Networks 28000 Series Fast Ethernet switches to form a multiprotocol LAN backbone. These two switches appear logically on the Terra Flora network diagram as three switches. One 28000 switch connects to the Terra Flora Enterprise level; the second 28000 switch connects to the Terra Flora Division, Department, and Desktop levels.
The ASN is connected to the first BLN by means of a dedicated leased line to provide access to branch servers and corporate systems. The Bay Networks router is configured to support a dial-on-demand feature, which is used when additional capacity is required between the corporate and remote regional offices. For example, during monthly end processing, transmission of data frequently exceeds the 128K capacity of the leased line. The Bay Network's dial-on-demand feature then establishes a second connection to provide additional bandwidth.
Recovery from leased line failure is provided through the ASN dial backup feature, which provides a two-point, fault-tolerance measure. Two lines are configured at Terra Flora. The second line is activated or used only when the first line goes down. This means that although two lines are available, usage charges apply only to the line that is being used. This reduces operational costs by delivering the connection only when needed and ensuring continued operation in the event of a network failure.
The entire network infrastructure is managed by the Bay Networks Optivity network management tools. These tools enable the network manager to configure the routers and switches, monitor and evaluate the network, and react to problems on the network from a central console.
The collapsed WAN backbone interconnects the Terra Flora LANs and computing devices across long distances by way of the T1 and T3 links. The LAN backbone ensures that traffic is directed to the destination over the best possible route and, when coupled with the switches' dedicated high-speed connections, ensures high data throughput. Because routing is employed on both the LAN and WAN backbones, all resources, such as nodes, servers, and computers, can interoperate, regardless of the type of network they are on and the distance between them.
Because of this connectivity, users at the New York retail store now have access to the applications and records contained in servers NENTS40B0FO1, NENTS40DIV01, NENTS40ENT01, EUNTS4ENT01, and EUNTS40DIV01, as well as to all information and applications at the Enterprise, Division, Department, and Desktop levels.
Security measures can be put in place in the router to block access to particular portions of the network. For example, filters can be configured in any of the BLNs to drop data destined for a network based on source address or destination address. The data packet information is examined and, if it is being sent to a specific server, the data will be discarded, thus limiting access to the network.
In the network diagram, the routers allow access from regional remote retail stores to corporate resources. Data is transmitted from these remote locations over WAN links, ensuring that individuals in the corporate and regional offices have needed information to satisfy current and future customer needs. This information is also passed to the appropriate corporate offices to maintain records, ensuring that all stores have adequate merchandise to sell to the consumer. Sales information from the retail stores can be sent in a timely fashion to the Enterprise and Division computers for processing inventory management, billing purposes, and so forth.
Stocking information, changes in products, sales incentive programs, advertising literature, and other information can be easily transmitted from corporate headquarters to the retail stores and all other remote Terra Flora sites over the internetwork.
The routers determine the best possible paths for sending data and avoiding breakdowns in communications. Through the router's lookup table, changes in the network are reported to the routers and the tables are updated with information about the new configuration. This enables IP traffic to be rerouted if, for example, a network change prevents the sent message from reaching its destination. This ensures continued communications.
Corporate data, such as employee lists, resource materials, and accounting facilities, are also accessible from anywhere no the internetwork through routing. Authorized users can access this information from their offices and interoperate with others around the corporation, using a variety of applications.
The Bay Networks Optivity console functions as a centralized point of administration for managing all network resources. Management servers offer a number of services including Logon Authentication, replicated User Account databases, centralized Network services, Name Resolution services, and Backup Services at the Enterprise level. These provide a consistent, master copy of common information and resources. A centralized architecture of file and print application servers is in place to provide heterogeneous file and print interfaces, integration services, backup services, and intranet services. All of these servers are accessible throughout the internetwork through the routers.
The configuration of the Bay Networks equipment is as follows:
BLN Base Unit with:
BLN Base Unit with:
28000 Series Switch
ASN Base Unit
Network Management Software