Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Asynchronous Transfer Mode wikipedia , lookup
Cracking of wireless networks wikipedia , lookup
Deep packet inspection wikipedia , lookup
Distributed firewall wikipedia , lookup
Zero-configuration networking wikipedia , lookup
Computer network wikipedia , lookup
Network tap wikipedia , lookup
Piggybacking (Internet access) wikipedia , lookup
Internet protocol suite wikipedia , lookup
Airborne Networking wikipedia , lookup
Recursive InterNetwork Architecture (RINA) wikipedia , lookup
Cisco Hierarchical Network Model RD-CSY2001-09/10 1 Outline Network Design and Planning for Enterprise networks Cisco 3 Layer hierarchical Model ◦ Core, Distribution and Access Layers ◦ Hub and spoke designs ◦ Mesh topologies RD-CSY2001-09/10 2 Internetworking Internetworking is the communication between two or more networks ◦ Requires many protocols and features to permit scalability manageability without constant manual intervention Large internetworks can consist of the three distinct components: 1. Campus networks, which consist of locally connected users in a building or group of buildings 2. Wide-area networks (WANs), which connect campuses together 3. Remote connections, which link branch offices and single users (mobile users and/or telecommuters) to a local campus or the Internet Typical Enterprise Network RD-CSY3021 3 High Level view of Enterprise Network RD-CSY2001-09/10 4 Why reference model for network design Large networks can be extremely complicated, ◦ with multiple protocols IPv4, IPv6, IPX, Appletalk ◦ detailed configurations, and ◦ diverse technologies Frame Relay, FDDI, ATM, Ethernet, Token Ring Hierarchy helps us summarize a complex collection of details into an understandable model Hierarchy, when used properly, makes network more predictable The Cisco hierarchical model can help you design, implement, and maintain a scalable, reliable, cost-effective hierarchical internetwork RD-CSY2001-09/10 5 Campus Networks A campus is a building or group of buildings all connected into one enterprise network that consists of many local area networks (LANs). ◦ A large campus with groups of buildings can also use WAN technology to connect the buildings Campus network generally optimized for the fastest functional architecture that runs on existing physical wire. Scalable to requirements of emerging applications Campus Network RD-CSY3021 6 Why Use a Hierarchical Model? Reduces workload on network devices ◦ Avoids devices having to communicate with too many other devices (reduces “CPU adjacencies”) Constrains broadcast domains Enhances simplicity and understanding Facilitates changes Facilitates scaling to a larger size Cisco’s Hierarchical Design Model Like OSI 7 layer model, Cisco hierarchical model is a three layered model. The layers from below are: ◦ Layer 1: Access ◦ Layer 2: Distribution ◦ Layer 3: Core A core layer of high-end routers and switches that are optimized for availability and speed A distribution layer of routers and switches that implement policies and segment traffic An access layer that connects users via hubs, switches, and other devices Hierarchical Network Design Enterprise WAN Backbone Campus A Core Layer Campus B Campus C Campus C Backbone Access Layer Building C-1 Building C-2 Distribution Layer Flat Versus Hierarchy Headquarters in Bedford Headquarter in Bedford Grimsby Branch Office Kelmarsh Branch Office Ashford Branch Office Flat Loop Topology Grimsby Branch Office Kelmarsh Branch Office Ashford Branch Office Whitby Branch Office Hierarchical Redundant Topology Mesh Designs Full and partial mesh designs are used in network design to provide redundancy or high availability Partial-Mesh Topology Full-Mesh Topology A Partial-Mesh Hierarchical Design Headquarters (Core Layer) Regional Offices (Distribution Layer) Branch Offices (Access Layer) A Hub-and-Spoke Hierarchical Topology Corporate Headquarters ◦ Common in enterprise networks ◦ Main location and satellite sites ◦ Simple design and trivial routing Branch Office Home Office Branch Office Single hub node Problems ◦ ◦ ◦ ◦ Single point of failure Bandwidth limitations High delay between sites Costs to backhaul to hub Simple Alternatives to Hub-and-Spoke Dual hub-and-spoke ◦ Higher reliability ◦ Higher cost ◦ Good building block Levels of hierarchy ◦ Reduce backhaul cost ◦ Aggregate the bandwidth ◦ Shorter site-to-site delay … 14 Avoid Chains and Backdoors Core Layer Distribution Layer Access Layer Backdoor Chain How Do You Know When You Have a Good Design? When you already know how to add a new building, floor, WAN link, remote site, ecommerce service, and so on When new additions cause only local change, to the directly-connected devices When your network can double or triple in size without major design changes When troubleshooting is easy because there are no complex protocol interactions to wrap your brain around Cisco’s SAFE Security Reference Architecture Enterprise Composite Network Model RD-CSY3021 18 Grouping Devices into Networks and Hierarchical Addressing Devices are grouped into sub-networks Based on geographical location Based on Functionality Departments Communication requirements RD-CSY2001-09/10 19 Network Designs: breaking into sub-networks Given a network requirement, find the optimum number of sub networks in the larger inter-network. ◦ Count on the basis of Departments Geographical locations.. Determine the total number of hosts in a network, accounting for present and future requirements Hosts include ◦ PCs, printers, servers, special devices RD-CSY2001-09/10 20 Campus Topology Design Use a hierarchical, modular approach Minimize the size of bandwidth domains Minimize the size of broadcast domains Provide redundancy ◦ Mirrored servers ◦ Multiple ways for workstations to reach a router for off-net communications Next Week Revisit IP Addressing Subnetting Class B subnetting RD-CSY2001-09/10 22