Network+ Guide to Networks 6th Edition

CEG 2400 FALL 2012 Chapter 10 Virtual Networks and Remote Access 1 Virtualization Its the emulation of a computer, operating system environment, or application: On a physical system Virtual machines (VMs)

Virtual workstations Virtual servers Can be configured to use different types of: CPU Storage drive NIC 2 Virtualization VM guests appears to user no different than a physical computer

Host Physical computer, one that VMs run on Guest Virtual machines Hypervisor Manages virtual machines (Software) Runs on Host 3

Elements of virtualization 4 Virtualization Advantages of virtualization

Efficient use of resources Cost and energy savings Fault and threat isolation Simple backups, recovery, and replication Disadvantages

Compromised performance Increased complexity Increased licensing costs Single point of failure 5 Top 10 Virtualization Technology Companies 1. VMWare (vSphere) 2. Microsoft (Hyper-V)

3. Citrix (Xen) 4. Oracle (VirtualBox) 5. Red Hat (KVM, built into Linux) 6. Amazon (Xen) 7. Google (KVM) 8. Virtual Bridges (VERDE) 9. Proxmox (KVM) 10. Parallels (OpenVZ) 6 Virtual Networks, Machines and

Adapters Virtual network Can be created to consist solely of virtual machines on a physical server, cant get off of host Most networks combine physical and virtual elements Virtualization program Assigns VMs software and hardware characteristics Often has an easy to use, step-by-step wizard Operating system images

Available for download online Network connection Requires virtual adapter (vNIC) Each vNIC has its own MAC Address 7 Specifying a VMs memory in VMware 8

Customizing vNIC properties in VMware 9 Virtual Switches and Bridges Virtual bridge or switch (terms can sometimes be synonymous) Automatically created when first VMs NIC is selected Connects VM with host Resides in RAM, configuration resides in file on host Hypervisor software controls virtual switches and

switch ports One host can support multiple virtual switches Switches still need a router to move traffic between them 10

Virtual Switches and Bridges Virtual switch Logically defined device Operates at Data Link layer Passes frames between nodes

Uplinks to physical NIC Virtual switch software has many more features available to it and can perform more complex operations Virtual bridge Connects vNICs with a network through physical NIC Passes frames between nodes using MAC address 11 Virtual servers on a single host connected with a virtual switch

12 Virtual switches exchanging traffic through routers 13 Virtual Switches 14 Virtual Bridge

KVM, XenServer, Open Source Xen and Hyper-V use a virtual bridge and not a virtual switch 15 Network Connection Types Must identify networking mode vNIC will use Frequently-used network connection types Bridged NAT Host-only

Bridged vNIC accesses physical network using host machines NIC Obtains own IP address, default gateway, and netmask from DHCP server on physical LAN 16 vNIC receiving IP address from external DHCP server

17 Selecting the Bridged option for a vNIC in VMware 18 Network Connection Types (contd.) NAT

vNIC relies on host to act as NAT device Obtains IP addressing information from host Virtualization software acts as a DHCP server Default network connection type in VMware, VirtualBox, and KVM Host-only VMs on one host can exchange data with each other and the host

Cannot communicate with nodes beyond the host Never receive or transmit data with hosts physical NIC 19 vNIC accessing a network in NAT mode 20 Selecting the NAT option for a vNIC in VirtualBox 21

Host-only network configuration 22 Virtual Appliances Virtual appliance includes: Image of operating system, software, hardware specifications, and application configuration Ready to go image

Most commonly used with virtual servers Popular functions Firewall E-mail solutions Network management Remote access

23 Virtual Networks and VLANs Virtual network Refers to how VMs connect with other virtual and physical network nodes Virtual network management Nearly identical to physical network management To add VMs to a physical VLAN:

Modify virtual switchs configuration Steps vary for different virtualization programs To increase performance Multiple NICs on Host for load sharing or fault tolerance Multiple NICs on guest for load sharing or fault tolerance 24 Multiple virtual servers connected to multiple VLANs 25

Multiple NICs on host and multiple NICs on guest 26 Remote Access Remote access Allows user to connect with LAN or WAN in different geographical location Allows access to shared resources as any other client that are on LAN or WAN Requires appropriate software

Popular remote access techniques 1. Dial-up networking 2. Microsofts Routing and Remote Access Service (RRAS), old version was Microsofts Remote Access Service (RAS) 3. Virtual Private Networks (VPN) 27 Dial-Up Networking Dialing directly into private networks or ISPs

remote access server Usually refers to connection using telephone lines Remote access server attached to group of modems Client must run dial-up software, with modem After authentication, user allowed access Remote access server can serve multiple users Low throughput, very slow Less popular today but still around 28

Remote Access Servers Accepts connections regardless of Internet connection type Can be dial-up, dsl, broadband, etc RRAS (Routing and Remote Access Service) Microsofts remote access software Available with Server 2003, 2008, 2008 R2, XP, Vista, and 7 operating systems Enables server to act as a router Includes multiple security provisions

29 Clients connecting with a remote access server 30 Remote Access Protocols SLIP (Serial Line Internet Protocol)

Earlier and less sophisticated than PPP Can only carry IP packets Requires significant amount of setup Does not support data encryption Asynchronous transmission Not around much anymore

PPP (Point-to-Point Protocol) Known as PPPoE when used over Ethernet Standard for connecting home computers to ISP Via DSL or broadband cable Requires connection software 31 Remote Virtual Computing Allows a workstation (client) to remotely access and control another workstation (host) Host may allow clients a variety of privileges

Can send keystrokes and mouse clicks to the host Receive screen output in return Appears as if you are on the workstation Thin client Workstation that uses software to access LAN Requires very little hard disk space or processing power Web client Software used to control another workstation

32 VNC, ICA Protocols used in a remote access Internet connection 33 Remote Virtual Computing Advantages Simple to configure

Runs over any connection type Single host can accept simultaneous connections from multiple clients Popular programs 1. Microsoft Remote Desktop (RDP) 2. VNC (Virtual Network Computing, open source) 3. ICA (Independent Computing Architecture, Citrix) 34

Remote Virtual Computing Remote desktop Comes with Windows client and server operating systems VNC (Virtual Network Computing) Open source system ICA (Independent Computing Architecture) Can work with virtually any operating system or application

Easy to use Costs money 35 VPNs (Virtual Private Networks) Logically defined networks over public transmission systems Traffic isolated from other traffic on same public lines Usually requires inexpensive software VPNs can be created on routers or firewalls (Unixbased)

Important considerations are Interoperability and security Types Site-to-site (VPN gateway to VPN gateway) Client-to-site (VPN client to VPN gateway) 36 Site-to-site VPN 37

Client-to-site VPN 38 VPNs Enterprise-wide VPN Can include elements of client-to-site and site-to-site models VPNs use encapsulation and encryption

Two major types of tunneling protocols used PPTP (Point-to-Point Tunneling Protocol) Microsoft and RRAS server L2TP (Layer 2 Tunneling Protocol) Developed by Cisco Standardized by IEFT More common of the two 39 Cloud Computing

Cloud computing is the use of computing resources (hardware and software) that are delivered as a service over a network. Cloud computing provisions data storage, applications, and services to multiple clients over a network. Cloud computing distinguishing features

Self-service and on-demand Elastic, can grow dynamically Supports multiple platforms Resource pooling and consolidation Metered service, can charge by different measures 40 Cloud Computing 4 Service models Infrastructure as a service (IaaS), physical or virtual

machines Platform as a service (PaaS), typically including operating system, database, and web server Software as a service (SaaS), application software NaaS (Network as a Service), Service provider offers customers complete set of networking services 41 Example of cloud computing 42

Cloud Computing Can provide virtual desktops Operating environments hosted virtually Different physical computer than one user interacts with Types of delivery

Public cloud Private cloud Community cloud Hybrid cloud 43 Summary Virtualization: emulation of a computer, operating

system environment, or application on a physical system VMs exist as files on physical computers hard disk Hypervisor software manages resource allocation and sharing among virtual machines Virtual switch allows VMs to communicate with each other and with nodes on a physical LAN or WAN Different methods of remote user access exist Cloud computing provides storage, applications, or services over a network 44

Misc PPP and PPPoE Remote Desktop Protocol top/aa383015(v=vs.85).aspx 45

End of Chapter 10 Questions 46

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