Configuration and Management of Networks

Transcription

1 Configuration and Management of Networks 2013/2014 tele1.dee.fct.unl/cgr

2 Programa Arquitecturas de Redes empresariais: Revisão dos principais tipos de rede e tecnologia associada Comutação: Domínios de colisão e difusão - VLANs como forma de dividir domínios de colisão. Configuração de agregados de Links com EtherChannel. Configuração de trunks para transporte de várias VLANs. As várias versões e configuração do protocolo Spanning tree (STP). Configuração de VLANs Privadas. Encaminhamento entre VLANs usando routers or multilayer switches.

3 Programa Encaminhamento: Endereçamento IPv4 e IPv6 EIGRP Desenho, configuração e verificação OSPF Desenho, configuração e verificação Route maps, access control lists e prefix lists BGP Desenho, configuração e verificação

4 Programa Service Provider Networks Redes de Acesso Metro Ethernet, VPLS: Services definitions for E- Line, E- LAN and E- Tree. MPLS based services, VPNs Layer 2 e Layer 3 Software defined Networks Separação entre control plane e forwarding plane (Open Flow) Virtualização

5 Avaliação : 1º Trabalho (tutorial + autónomo) Série de trabalhos de configuração em Layer 2 e Layer 3. Semana de 27 de Outubro 25 % 2º Trabalho (tutorial+autónomo) Série de configuração em Layer 3 + (programação de um cenário num controlador OpenFlow?) Semana de 8 de Dezembro - 25% GNS3 hdp:// Packet Tracer hdp:// PacketTracer.html Mininet hdp://mininet.org/

6 Avaliação : Teste teórico Redes empresariais, switching e endereçamento, Eigrp 28 Outubro 25% Teste teórico OSPF BGP, Service Provider Networks e SDNs 9 Dezembro 25%

7 2012 General concepts Physical components of a Network End devices: Serve as endpoints in the network, sending and receiving data. Personal computers (PCs): PC Servers TFTP Interconnections: Components that provide a means for data to travel from one point to another point in the network: Network interface cards (NICs) that translate the data produced by the computer into a format that can be transmided over the local network Network media, such as cables or wireless media. Connectors that provide the connection points for the media.

8 2012 General concepts Typical Network Diagram Remote Class SSH ISP VPN Fa0/1 Con 0 Fa0/11 SwitchX Fa0/12 Fa0/ /24 Fa0/0 Con 0 Fa0/1 S0/0/0 RouterX TFTP Main Router

9 2012 General concepts User applications User applications - Enable users to be connected to one another through the various types of software. Owners rely on these applications Network becomes critic! System-to-System Batch Applications Bulk data transfer User Interactive Applications User requests server and waits for a reply User Real-Time Applications Voice over IP (VoIP) and video applications

10 2012 General concepts Network characteristics Speed: Speed is a measure of how fast data is transmided over the network. A more precise term would be data rate. Cost: Cost indicates the general cost of components, installation, and maintenance of the network. Security: Security indicates how secure the network is, including the data that is transmided over the network. Availability: Availability is a measure of the probability that the network will be available for use when required.

11 2012 General concepts Network characteristics Scalability: Scalability indicates how well the network can accommodate more users and data transmission requirements. Reliability: Reliability indicates the dependability of the components (routers, switches, PCs, and so on) that make up the network. Measured as a probability of failure, or mean time between failures (MTBF). Topology: Networks have two types of topologies: the physical topology, which is the arrangement of the cable, network devices, and end systems (PCs and servers), and the logical topology, which is the path that the data signals take through the physical topology.

12 2012 General concepts internetworking models The OSI Reference Model Upper layers Application Provides a user interface Presentation Presents data Handles processing such as encryption Session Keeps different applications data separate Transport Network Data Link Physical

13 2012 General concepts internetworking models The OSI Reference Model Lower Layers Transport Provides reliable or unreliable delivery Performs error correction before retransmit Network Provides logical addressing, which routers use for path determination Data Link Physical Combines packets into bytes and bytes into frames Provides access to media using MAC address Performs error detection not correction Moves bits between devices Specifies voltage, wire speed, and pin-out of cables

14 2012 General concepts internetworking models The OSI Reference Model Layer Functions

15 2012 General concepts internetworking models The OSI Reference Model Peer to Peer communication Sender Receiver Application Presentation Session Transport Network Data Link Physical Segments Packets Frames Bits Network Application Presentation Session Transport Network Data Link Physical

16 2012 General concepts internetworking models The Transmission Control Protocol / Internet Protocol (TCP/IP) Created by the DoD TCP/IP Protocol Stack OSI Model Application Application Protocols Presentation Session Application Layers Transport Transport Internet Network Access Networks Network Data Link Physical Data Flow Layers

17 2012 General concepts internetworking models (TCP/IP) Protocol suite Transport

18 2012 General concepts Summary A network is a connected collection of computing devices that communicate with each other to carry data. There are four major categories of physical components: computers, interconnections, switches, and routers. Resources that are shared in a computer network include: data and applications, storage devices, and backup devices. Common network user applications include e- mail, web browsers, instant messaging, collaboration, and databases. Networks are described in terms of: speed, cost, security, availability, scalability, reliability, and topology. Physical topology describes the layout for wiring the physical devices, the logical topology how information flows.

19 2012 General concepts internetworking models Summary The OSI reference model defines the network functions that occur at each layer. The physical layer defines the electrical, mechanical, procedural, and functional specifications of the physical link between end systems. The data link layer defines how data is formaded for transmission and handles how packets are placed on the media. The network layer provides connectivity and path selection between two host systems that might be located on geographically separated networks. The transport layer segments data from the system of the sending host and reassembles the data into a data stream on the system of the receiving host.

20 2012 General concepts internetworking models Summary The session layer establishes, manages, and terminates sessions between two communicating hosts. The presentation layer ensures that the information sent at the application layer of one system is readable by the application layer of another system. The application layer provides network services, such as e- mail, file transfer, and web services, to applications of the users. TCP/IP is now the most widely used protocol due to its flexible addressing, usability by most platforms, many tools and utilities, and the need to be connected to the Internet. The OSI reference model and the TCP/IP stack are similar in structure and function, with correlation at the physical, data link, network, and transport layers.

21 Using the Top- Down Approach to Network Design Start your design here. Application Presentation Session Design down the OSI model. Transport Network Data Link Physical Top-Down Design Method

22 Using the Top- Down Approach to Network Design Analyze the requirements and applications of the organization. Complete the design from the top of the OSI reference model to the bodom: Define requirements at the upper OSI layers(application, presentation, and session). Specify the infrastructure that is required in the lower OSI layers (transport, network, data link, and physical). Gather additional data on the network as it can influence the logical and physical design. Adapt the design to the new data as required.

23 Using the Top- Down Approach to Network Design IP Network QoS QoS IP Routing (Delay QoS) Cisco Unified Communications Manager Application layer requirement : VoIP IP routing and QoS needed at Transport and Network layers Design includes IP- enabled routers (and other devices not shown in the figure). VoIP needs the network to manage the delay with specific QoS mechanisms.

24 The Hierarchical Network Model Core High-Speed Switching Distribution Access Policy-Based Connectivity Local and Remote Workgroup Access

25 The Hierarchical Network Model Access layer: The first tier or edge of the campus. It is the place where end devices (such as PCs, printers, cameras, and so on) adach to the wired portion of the campus network. Distribution layer: In the campus design, this layer has a unique role in that it acts as a services and control boundary between the access and the core. Aggregation point for all the access switches, providing connectivity and policy services for traffic flows within the access- distribution block. Core layer: In some ways, this layer is the simplest, yet most critical, part of the campus. It provides a limited set of services and is designed to be highly available and operate in an always- on mode.

26 The Hierarchical Network Model WAN Internet PSTN Workstations Access Layer Distribution Layer Layer 2 or Layer 3 Switching in Access Layer 3 Switching in Distribution Core Layer Layer 3 Switching in Core Servers Servers Connected Directly to Data Center Distribution

27 Access Layer Functionality Provides end- device connectivity Supports the connectivity of any end devices it can also extend the network out one more level (IP phones and wireless APs are key examples of this). In the campus environment, incorporates LAN access devices with ports. In the WAN environment, the access layer provides remote users or sites with access to the campus network through a wide- area technology such as MPLS. Access is granted only to authenticated users or devices. Provides QoS and policy application.

28 Access Layer Functionality Provides end- device connectivity You can provide access to end devices as part of two scenarios: Using Layer 2 switching (typical campus) Using Layer 3 switching (routed) Access Distribution Core Distribution Access

29 Distribution Layer Functionality Traditional Campus Network Layer 2 Switching in Wiring Closet Layer 2 Access Distribution Layer 2 Layer 3 Layer 3 Routing Boundary, Concentration of Access Attachments, Packet Filtering, Policing Layer 3 Core Route Summarization, Eventual Load Balancing Layer 3 Switching in Core Traditional Campus Network Distribution Layer Example Access with Layer 2 switches with high- speed trunk ports towards distribution The distribution switches: Layer 2 switching on downstream towards access. Layer 3 switching on upstream ports towards the core. Route summarization is configured on interfaces toward the core layer.

30 Distribution Layer Functionality Routed Network Layer 2 Access EIGRP Layer 3 Switching in Wiring Closet Route Filtering Toward the Access Layer Layer 3 Distribution Layer 3 Routing Boundary, Policy-Based Routing, First- Hop Redundancy, Policing Core Layer 3 Route Summarization, Eventual Load Balancing Layer 3 Switching in Core Routed Campus Network Distribution Layer Example Access with Layer 3 switches The distribution uses Layer 3 switches Route filtering in interface towards Access Route summarization is configured on interfaces toward the core layer.

31 Core Layer Functionality High- speed backbone that is designed to switch packets as fast as possible. High level of redundancy should not perform any packet manipulation Implements scalable protocols and technologies, alternate paths, and load balancing. Traditional switched campus network: Step 1. A packet is Layer 2 switched toward the distribution switch. Step 2. Distribution switch performs Layer 3 switching towards the core Step 3. The packet is Layer 3 switched across the enterprise core. Step 4. The receiving distribution switch performs Layer 3 switching toward an access LAN. Step 5. The packet is Layer 2 switched across the access LAN to the destination host.

32 High availability considerations Redundant distribution layer switches Redundant connections to the core

33 Modular Approach in Network Design Separate the network in to functional areas that are referred to as modules. Enterprise Campus Enterprise Edge Service Provider Building Access E-Commerce Enterprise Branch ISP A Building Distribution Internet Connectivity ISP B Campus Core Enterprise Data Center Remote Access and VPN PSTN Data Center Network Management WAN and MAN Site-to-Site VPN Frame Relay/ATM Enterprise Teleworker

34 Modular Approach in Network Design Enterprise Edge Area E-Commerce Module Database Servers Application Servers Web Servers Service Provider Modules ISP A Module Internet Internet Connectivity Module Public Servers Edge Distribution Internet ISP B Module Remote Access and VPN Module VPN and IPsec PSTN Module PSTN WAN and MAN and Site-to-Site VPN Module Frame Relay and ATM Module Frame Relay/ ATM/MPLS/...

35 Service Provider Networks Residential Services A popular strategy to maximize service revenues and minimize subscriber turnover is to offer a complete set of bundled triple-play services to residential subscribers that include: Voice High-speed Internet Broadcast TV and Video On Demand (VoD) Business Services Business subscribers are an important segment of many service providers customer base. The main business services that must be provided by the network today are: MPLS VPN Carrier Ethernet connectivity Managed services

36 Service Provider Networks Mobile Backhaul Provide robust and flexible IP transport networks to mobile service providers Architecture: