PLANEAMENTO E GESTÃO DE REDES INFORMÁTICAS COMPUTER NETWORKS PLANNING AND MANAGEMENT

Transcription

1 Mestrado em Engenharia Informática e de Computadores PLANEAMENTO E GESTÃO DE REDES INFORMÁTICAS COMPUTER NETWORKS PLANNING AND MANAGEMENT Metodologia de Projecto 4 - Project Methodology 4 1

2 Hierarchical Enterprise Network Design 2

3 Hierarchical Network Design The hierarchical network design model allows the design of a modular topology using scalable building blocks to meet evolving needs. The modular design makes the network easy to scale, understand, and troubleshoot by promoting deterministic traffic patterns. The building block components are the Access layer, the Distribution layer, and the Core (backbone) layer. The principal advantages of this model are its hierarchical structure and its modularity. 3

4 Hierarchical Network Design 4

5 Hierarchical Network Design In a hierarchical design, the capacity, features, and functionality of a specific device are optimized for its position in the network and the role that it plays, promoting scalability and stability. The number of flows and their associated bandwidth requirements increase as they traverse points of aggregation and move up the hierarchy from access to distribution to core. Functions are distributed at each layer. A hierarchical design avoids the need for a fully-meshed network in which all network nodes are interconnected. In a hierarchical design, the building blocks of modular networks are easy to replicate, redesign, and expand, avoiding the redesign of the whole network each time a module is added or removed. In a hierarchical design, distinct building blocks can be put in-service and taken out-of-service without impacting the rest of the network. This capability facilitates troubleshooting, problem isolation, and network management. 5

6 Enterprise Hierarchical Network Design 6

7 Enterprise Hierarchical Network Design 7

8 The Core Layer The Core serves as the Backbone for the network. The Core needs to be fast and extremely resilient because every building block depends on it for connectivity. The core layer should be designed as a high-speed, Layer 3 (L3) switching environment utilizing only hardware-accelerated services. 8

9 The Distribution Layer The Distribution layer aggregates nodes from the access layer, protecting the core from high-density. The Distribution layer creates a fault boundary providing a logical isolation point in the event of a failure originating in the access layer. Load balancing, Quality of Service (QoS), and ease of provisioning are key considerations for the Distribution layer. Typically deployed as a pair of L3 switches for its connectivity to the Core of the network and L2 services for its connectivity to the Access layer. High Availability in the Distribution layer is provided through dual equal-cost paths both to the Core and from the Access layer. 9

10 The Access Layer The Access layer is the first point of entry into the network for edge devices, end stations, and IP phones. The switches in the Access layer are connected to two separate Distribution layer switches for redundancy. A robust Access layer provides the following key features: High availability (HA) supported by many hardware and software attributes. Inline power (POE-Power over Ethernet) for IP telephony and wireless access points, allowing the convergence of voice and data in the network and providing roaming WLAN access for users. 10

11 CISCO Enterprise Architecture Framework A Framework for an Enterprise Branch Architecture 11

12 CISCO Enterprise Architecture Enterprise Branch Architecture Internet WAN 12

13 Enterprise Architecture Lifecycle 13

14 Date Center Architecture 14

15 Data Center Architecture Data Centers are composed of devices that provide the following functions: Ensuring network connectivity, including switches and routers Providing network and server security, including firewalls and Intrusion Detection Systems (IDSs) Enhancing availability and scalability of applications, including load balancers, Secure Socket Layer (SSL) offloaders and caches 15

16 Data Center Architecture Data Center infrastructure design - critical requirements: High Availability - Avoiding a single point of failure and achieving fast and predictable convergence times Scalability - Allowing changes and additions without major changes to the infrastructure, easily adding new services, and providing support for hundreds dual-homed servers Simplicity - Providing predictable traffic paths in steady and failover states, with explicitly defined primary and backup traffic paths Security - Prevent flooding, avoid exchanging protocol information with rogue devices, and prevent unauthorized access to network devices 16

17 Typical Data Center Architecture 1 17

18 Typical Data Center Architecture 2 18

19 Data Center Architecture models The multi-tier model: The multi-tier model is the most common design in the enterprise. It is based on the web, application, and database layered design supporting commerce and enterprise business ERP and CRM solutions. The multi-tier model relies on security and application optimization services to be provided in the network. The server-cluster model: The server cluster model is commonly associated with high-performance computing (HPC), parallel computing, and high-throughput computing (HTC) environments. 19

20 Data Center Multi-Tier model The multi-tier data center model is dominated by HTTP-based applications in a multi-tier approach. The following three tiers are used: Web-servers Application servers Database servers Multi-tier server farms can provide improved resiliency and security. Resiliency is improved because a server can be taken out of service while the same function is still provided by another server belonging to the same application tier. Security is improved because an attacker can compromise a web server without gaining access to the application or database servers. Web and application servers can coexist on a common physical server; the database typically remains separate. 20

21 Data Center Multi-Tier model 21

22 Data Center Multi-Tier model 22

23 Load Balancing 23

24 Data Center Server-Cluster model When designing a large enterprise servercluster network, it is critical to consider specific objectives. No two clusters are exactly alike; each has its own specific requirements and must be examined from an application perspective to determine the particular design requirements. Take into account the following technical considerations: Latency, Mesh/partial mesh connectivity, High throughput, Oversubscription ratio, Jumbo frame support, Port density 24

25 Server-Cluster Two-Tier model 25

26 Server-Cluster Three-Tier model 26

27 Enterprise Campus Architecture 27

28 Enterprise Campus (High Level) 28

29 Campus Features 29

30 EXAMPLE of an Enterprise Architecture for a Retail solution 30

31 Solution: Small Store example 31

32 Solution: Large Store example 32

33 33

34 References and Readings " Documents: " CISCO, Data Center: Infrastructure Architecture SRND, Solutions Reference Network Design, March " CISCO, Cisco Data Center Infrastructure 2.5 Design Guide, December 2007 " CISCO, Infrastructure Protection and Security Service Integration Design for the Next Generation WAN Edge v2.0, " CISCO, Services Ready Large Branch Network System Assurance Guide, November " CISCO, Campus Network for High Availability Design Guide, May " CISCO, Enterprise Campus 3.0 Architecture: Overview and Framework, 2008 " Soluções Networking IP da PT: " " Soluções Corporate Networking da NOVIS: " 34