Campus Network Architectures and Technologies

Ningguo Shen, Bin Yu, Mingxiang Huang, Hailin Xu

• Publisher: CRC Press
• Year: 2021
• ISBN:
  9781000375978
• Edition: 1
• Topic: Computer Science
• Subtopic: Computer Networking
• Index: Computer Science

Campus Network Architectures and Technologies begins by describing the service challenges facing campus networks, and then details the intent-driven campus network architectures and technologies of Huawei Cloud Campus Solution. After reading this book, you will have a comprehensive understanding of next-generation campus network solutions, technical implementations, planning, design, and other know-how. Leveraging Huawei's years of technical expertise and practices in the campus network field, this book systematically describes the use of technical solutions such as virtualization, big data, AI, and SDN in campus networks. You will be able to reconstruct campus networks quickly and efficiently utilizing this informative description. Additionally, this book provides detailed suggestions for campus network design and deployment based on Huawei's extensive project implementation experience, assisting with the construction of automated and intelligent campus networks required to cope with challenges.

This is a practical, informative, and easy-to-understand guide for learning about and designing campus networks. It is intended for network planning engineers, network technical support engineers, network administrators, and enthusiasts of campus network technologies.

Authors

Ningguo Shen is Chief Architect for Huawei's campus network solutions. He has approximately 20 years' experience in campus network product and solution design, as well as a wealth of expertise in network planning and design. Mr. Shen previously served as a system engineer for the campus switch, data center switch, and WLAN product lines, and led the design of Huawei's intent-driven campus network solution.

Bin Yu is an Architect for Huawei's campus network solutions. He has 12 years' experience in campus network product and solution design, as well as extensive expertise in network planning and design and network engineering project implementation. Mr. Yu once led the design of multiple features across various campus network solutions.

Mingxiang Huang is a Documentation Engineer for Huawei's campus network solutions. He has three years of technical service experience, and four years of expertise in developing campus network product documentation. Mr. Huang was previously in charge of writing manuals for Huawei router and switch products. He has authored many popular technical series, including Be an OSPF Expert, Insight into Routing Policies, and Story behind Default Routes.

Hailin Xu is a Documentation Engineer for Huawei's campus network solutions. He has two years of marketing experience in smart campus solutions, and six years of expertise in developing network products and solution documentation. Extremely familiar with Huawei's campus network products and solutions, Mr. Xu was previously in charge of writing manuals for Huawei routers, switches, and campus network solutions. In addition, he has participated in smart campus marketing projects within such sectors as education, government, and real estate.

CHAPTER 1

Getting to Know a Campus Network

Communication networks are ubiquitous in today’s information society, and campus networks are their strategic core. Before discussing campus networks, let us define what a campus is. A campus is typically a fixed area in which infrastructure is deployed. Some examples of campuses include factories, government agencies, shopping malls, office buildings, school campuses, and parks. It can be said that everything in our cities, except roads and residential areas, is composed of campuses.

According to statistics, campuses are where 90% of urban residents work and live; everyone spends an average of 18 hours every day in a campus of some sort; 80% of a country’s Gross Domestic Product (GDP) is created inside campuses. The key to campuses lies in their underlying infrastructure, of which campus networks are an indispensable part. Campus networks are a key enabler to bridge campuses of all types to the digital world. They are playing an ever-increasingly significant role in our daily office work, R&D, production, and operational management. In this chapter, we will talk about the basic concepts and evolution of campus networks.

1.1 Campus Network Overview

As the name implies, a campus network is a network within a campus that we use for work and life. Campuses vary in size and industry attributes. Likewise, campus networks vary in type and form. However, despite the variety among them, campus networks share unified component models at different layers.

What is a campus network? How do they differ? What do they consist of? Let us find these answers together.

1.1.1 What Is a Campus Network?

All of us access various networks throughout our daily life, of which we are not actively aware. For example, when we return home at the end of the day, most of our phones automatically connect to the Wi-Fi network.

These home networks can be simple or complex. A simple home network may have just one wireless router that provides Internet access. A complex home network, however, may serve more devices and be designed for the smart life that we are experiencing now. Specifically, a complex home network can provide high-speed network services for many intelligent terminals at home, including televisions, sound systems, mobile phones, and personal computers. It can also connect to a Network Attached Storage (NAS) system to offer services such as secure data storage, automatic content acquisition, and information sharing. Similarly, the home network can interwork with an intelligent security protection system to remotely monitor the home environment, intelligently detect threats, and generate alarms accordingly. By interconnecting with an Internet of Things (IoT) system, the home network can provide automatic or remote control of various home appliances and intelligent devices. For example, an air conditioner can be turned on in advance while on the way home, so we can get comfortable the moment we open the door.

In most cases, the home network is connected externally to a carrier’s Metropolitan Area Network (MAN). Through the MAN, the carrier provides enterprise and individual users with a wide range of telecommunication Internet services, typically including Internet connections, private lines, and Virtual Private Networks (VPNs), as well as various value-added services based on Internet services, such as Internet TV services. A MAN covers cities and towns and generally has three layers: core, aggregation, and access layers. The core layer is composed of routers that use Wide Area Network (WAN) technologies; the aggregation layer is formed of Ethernet switches adopting Local Area Network (LAN) technologies; and the access layer consists of Ethernet switches or alternatively Optical Line Terminals (OLTs) and Optical Network Units (ONUs) that use Passive Optical Network (PON) technologies. MANs around the globe are interconnected through WANs to form a global Internet.

As such, no matter where or when we take out mobile phones to access the Internet, we are using a mobile communication network. Generally speaking, a mobile communication network is constructed and operated by a carrier. It is made up of a series of base stations, Base Station Controllers (BSCs), a backhaul network, and a core network. With a mobile communication network, users in a wide geographical area can enjoy high-speed wireless Internet access and voice call services at ease.

Apart from the preceding networks, there is another type of network that we often encounter.

When we walk onto a campus for study, step into offices for work, go shopping, go sightseeing, or check into a hotel, we may notice that these places are also covered by networks. On the campus, we have a closed office network for teachers and also a semi-open network for students to access learning resources and browse the Internet. Inside an enterprise, we have a closed internal network for employees, facilitating their office work while ensuring security. In a shopping mall or hotel, we have not only a closed office network for employees, but also an open network for customers that provides high-quality services to enhance enterprise competitiveness. All of these networks belong to campus networks.

A campus network is a fully connected LAN in a continuous and limited geographical area. If a campus has many discontinuous areas, the networks at these discontinuous areas are considered to be multiple campus networks. Many enterprises and schools have multiple campus networks that are connected through WAN technologies.

Campus networks can be large or small. Small Office Home Office (SOHO) is a typical example of a small campus network, while school campuses, enterprise campuses, parks, and shopping malls are examples of large campus networks. Regardless, the scale of a campus network is limited. Typically, a large campus network, such as a university/college campus or an industrial campus, is constrained to a few square kilometers. Within this scope, we can use LAN technologies to construct the network. A campus beyond this scope is usually considered a metropolitan area, and the network is regarded as a MAN, involving related MAN technologies.

Typical LAN technologies used on campus networks include Institute of Electrical and Electronics Engineers (IEEE) 802.3 Ethernet technologies (for wired access) and IEEE 802.11 Wi-Fi technologies (for wireless access).

Typically, a campus network is managed by one entity only. If multiple networks within an area are managed by multiple entities, we generally consider these networks as multiple campus networks. If these networks are instead managed by the same entity, these networks are regarded as multiple subnets of the same campus network.

1.1.2 How Do Campus Networks Differ?

A campus network serves a campus and organizations inside the campus. Due to the diversity of campuses and their internal organizations, campus networks differ in size and form. These differences are detailed in the five aspects below:

1. Network scale
   Campus networks can be classified into three types: small, midsize, and large campus networks, each differing in the number of terminal users or Network Elements (NEs). This is described in Table 1.1. Sometimes, the small campus network and midsize campus network are collectively called small- and medium-sized campus networks.

   TABLE 1.1 Campus Network Scale Measured by the Number of Terminal Users or NEs

   Campus Network Category	Terminal Users	NEs
   Small campus network	<200	<25
   Midsize campus network	200–2000	25–100
   Large campus network	>2000	>100

   A large campus network generally has complex requirements and structures, resulting in a heavy operations and maintenance (O&M) workload. To handle this, a full-time professional O&M team takes charge of end-to-end IT management, ranging from campus network planning, construction, and O&M to troubleshooting. This team also builds comprehensive O&M platforms to facilitate efficient O&M. In contrast to large campus networks, small/midsize campus networks are budget-constrained and usually have no full-time O&M professionals or dedicated O&M platforms. Typically, only one part-time employee is responsible for network O&M.
2. Service targets
   If we look at campus networks from the perspective of service targets, we will notice that some campus networks are closed and restrictive, only allowing internal users, while others are open to both internal and external users. The source of network security threats differs between closed campus networks and open campus networks. Therefore, they both have distinct network security requirements and solutions.
   Users on a closed campus network are typically internal employees. Their online behaviors are relatively fixed and can be effectively controlled through internal rules and regulations as well as reward and punishment. Therefore, the threats to a closed campus network mainly come from external intrusion. For this reason, a closed campus network usually uses a stronghold model to prevent unauthorized access from external and internal networks. Specifically, network admission control (NAC) is introduced to authenticate user names, accounts, tokens, certificates, and other credentials in order to prevent non-internal users from accessing the network. Additionally, firewalls are deployed at the borders of different security zones, for example, at the network ingresses and egresses.
   Open campus networks paint a different picture. An open campus network aims to serve the public as much as possible. To this end, network access authentication needs to accommodate both convenient public access and effective user identification. A viable solution is to use a mobile number plus a short message service (SMS) verification code or adopt social account authentication. These approaches can simplify account management. However, public network access is unpredictable, and there may be many network security threats. As such, a user behavior control system is often deployed inside the network to prevent intentional and unintentional illegal behaviors. For example, if a user terminal is infected with a network virus, the virus may spread to attack the entire network system. To contain attacks, the user behavior control system must be able to identify user behaviors as well as isolate and clean up traffic from these users. This ensures that users can access the Internet as normal, without affecting other users on the network.
   In real-world situations, a campus network usually has both closed and open subnets. A typical campus network that serves the public always has a closed subnet for internal office and administration purposes. Likewise, a campus network designed for internal personnel is typically partially open to outsiders. For example, an enterprise campus network opens up some portions of the network to guests for improved communication and collaboration. Some parts of an e-Government campus network are open for citizens who will enjoy convenient government services. In these cases, the closed subnet and open subnet belong to different security zones and must be isolated from each other. Typical isolation methods include physical isolation, logical network isolation, and firewall isolation. For networks that require strong security, physical isolation is generally used. That is, the closed and open subnets cannot communicate with each other at all.
3. Service support
   Campus networks can be classified into single-service and multi-service campus networks, depending on the services carried. The complexity of services carried on the campus network determines the network complexity.
   In the beginning, campus networks carried only data services, and other services were supported by disparate dedicated networks. Currently, most small- and medium-sized enterprises have a limited number of network services. For example, a small enterprise that rents offices in an office building uses the network infrastructure provided by the office building owner. Therefore, small enterprise campus networks typically require only internal data communication services. Generally speaking, a single-service campus network has a simple architecture.
   An advanced large campus network is a completely different story. It usually serves an independent large campus, where various basic services, such as firefighting management, video surveillance, vehicle management, and energy consumption control, are provided. If a dedicated network was deployed for each basic service, the cost would be prohibitively high and O&M would be terribly complex. To change this, digital and Ethernet technologies are gradually introduced for these basic services. Doing so facilitates the use of mature Ethernet, and a campus network is gradually made capable of supporting multiple services. The network carries multiple services with different requirements, which are isolated from each other and effectively ensured. Due to this, the campus network architecture is becoming more and more complex and virtuali...

Table of contents

• Cover
• Half Title
• Series Page
• Title Page
• Copyright Page
• Table of Contents
• Summary
• Introduction
• Acknowledgments
• Authors
• Chapter 1 ◾ Getting to Know a Campus Network
• Chapter 2 ◾ Campus Network Development Trends and Challenges
• Chapter 3 ◾ Overall Architecture of an Intent-Driven Campus Network
• Chapter 4 ◾ Building Physical Networks for an Intent-Driven Campus Network
• Chapter 5 ◾ Building Virtual Networks for an Intent-Driven Campus Network
• Chapter 6 ◾ Automated Service Deployment on an Intent-Driven Campus Network
• Chapter 7 ◾ Intelligent O&M on an Intent-Driven Campus Network
• Chapter 8 ◾ E2E Network Security on an Intent-Driven Campus Network
• Chapter 9 ◾ Open Ecosystem for an Intent-Driven Campus Network
• Chapter 10 ◾ Intent-Driven Campus Network Deployment Practices
• Chapter 11 ◾ Huawei IT Best Practices
• Chapter 12 ◾ Intent-Driven Campus Network Products
• Chapter 13 ◾ Future Prospects of an Intent-Driven Campus Network
• Acronyms and Abbreviations