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VKSF 423 System Administration III

VKSF 423 System Administration III. Thin Client Computing. Announcements. Lab: Implementation terminal servers and thin clients. Recap from Last Time. What do our users do? What computing resources do they need to accomplish their tasks?

patricia-villarreal
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VKSF 423 System Administration III

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  1. VKSF 423 System Administration III Thin Client Computing

  2. Announcements • Lab: • Implementation terminal servers and thin clients.

  3. Recap from Last Time • What do our users do? • What computing resources do they need to accomplish their tasks? • If the minimal desktop computers we can buy far exceed our needs what are our options?

  4. What are the trends in the Business World • Incredible cost pressures • Rising salaries for skilled systems administrators • Desire to decrease TCO • Historically low interest rates make capital investments attractive by lowering internal rate of return in ROI analysis

  5. Thin-client Devices • Only needs to process keyboard input and screen output • No hard drive, no CDROM drive, no floppy drive, no moving parts • Cannot be used away from the network • Cheap and easy to replace • Can any device be thin?

  6. Why Thin Clients? • Provide ability to aggregate computing resources in servers instead of spreading them around in clients • Centralization • Consolidation • Virtualization

  7. Thin-client Model Benefits • Lower total cost of ownership (TCO) • Easier software installation, uninstallation and maintenance • Centralized support, access control, and administration • Lowered security risks • Uses existing infrastructure • Lower power consumption • Applications available anywhere on demand • Disaster recovery • No end of life

  8. Thin-client Model Limitations • Management – Business side • 3D applications • Specialized hardware needs • Laptops • Are these valid limitations? • Can we think of ways of getting around them and still keep the thin client model?

  9. The WYSE Choice • Biggest provider of thin clients • Hardware Devices • Terminal Devices • Tablet PCs • Software • Management • Rapport • Alcatraz • Speed • Expedian

  10. Available Server Technologies • Windows Terminal Server • Citrix MetaFrame Presentation Server • Linux Terminal Server Project • Sun and Sun Rays • VNC • Nomachine

  11. Comparative Points • How thin is thin? • Desktop and server side hardware requirements • Where does the processing actually take place? • What is going over the wire? • What management tools are available? • Ratio of sysadmins to desktops • Characteristics of your enterprise • Future technology needs

  12. LTSP • Linux Terminal Server Project • Supports many devices and platforms • Supports many services • “Zero cost” solution • No software or hardware licensing • No operating system installed locally • Limited points of failure • Freely available “cookbook” directions

  13. LTSP Client Side • Network Interface Card • Video Card Chipset • Monitor Information • Etherboot, PXE, or eprom • If the client has more memory, it can be configured to store programs locally

  14. LTSP Server side • Required • Syslog • NFS • DHCP • TFTP • LTSP Core • LTSP Kernel • LTSP X Core • LTSP X Fonts • Optional • NIS

  15. Files Modified by LTSP • LTSP Initialization Script • /etc/hosts • /etc/dhcpd.conf • /opt/ltsp/i386/etc/lts.conf • /etc/exports • /etc/xinetd.d/tftp • XDMCP

  16. LTSP - Theory of Operation • Client boots into from the network • DHCP • TFTP • DHCP • NFS • SYSLOG • XDMCP

  17. Frame 1 Message type: Boot Request (1) Client hardware address: 00:50:ba:d3:a0:ab Option 53: DHCP Message Type = DHCP Discover Option 57: Maximum DHCP Message Size = 1500 Option 55: Parameter Request List 1 = Subnet Mask 3 = Router 12 = Host Name 43 = Vendor-Specific Information Frame 2 Message type: Boot Reply (2) Your (client) IP address: 10.110.53.2 Next server IP address: 10.110.53.1 Client hardware address: 00:50:ba:d3:a0:ab Boot file name: /lts/vmlinuz-2.4.19-ltsp-1 Option 53: DHCP Message Type = DHCP Offer Option 54: Server Identifier = 10.110.53.1 Option 51: IP Address Lease Time = 6 hours Option 1: Subnet Mask = 255.255.255.0 Option 3: Router = 10.110.53.254 Option 12: Host Name = "ws001" LTSP Etherboot DHCP Exchange

  18. Frame 3 Message type: Boot Request (1) Client hardware address: 00:50:ba:d3:a0:ab Option 53: DHCP Message Type = DHCP Request Option 54: Server Identifier = 10.110.53.1 Option 50: Requested IP Address = 10.110.53.2 Option 57: Maximum DHCP Message Size = 1500 Option 60: Vendor class identifier = "Etherboot-5.0" Option 55: Parameter Request List 1 = Subnet Mask 3 = Router 12 = Host Name 43 = Vendor-Specific Information 17 = Root Path Frame 4 Message type: Boot Reply (2) Your (client) IP address: 10.110.53.2 Next server IP address: 10.110.53.1 Client hardware address: 00:50:ba:d3:a0:ab Boot file name: /lts/vmlinuz-2.4.19-ltsp-1 Option 53: DHCP Message Type = DHCP ACK Option 54: Server Identifier = 10.110.53.1 Option 51: IP Address Lease Time = 6 hours Option 1: Subnet Mask = 255.255.255.0 Option 3: Router = 10.110.53.254 Option 12: Host Name = "ws001" Option 17: Root Path = "10.110.53.1:/opt/ltsp/i386“ LTSP Etherboot DHCP Exchange

  19. Frame 1 Src Addr: 10.110.53.2 Dst Addr: 10.110.53.1 Trivial File Transfer Protocol Opcode: Read Request (1) Source File: /lts/vmlinuz-2.4.19-ltsp-1 Type: octet Option: blksize = 1432 Frame 2 Src Addr: 10.110.53.1 Dst Addr: 10.110.53.2 Trivial File Transfer Protocol Opcode: Option Acknowledgement (6) Option: blksize = 1432 Frame 3 Src Addr: 10.110.53.2 Dst Addr: 10.110.53.1 Trivial File Transfer Protocol Opcode: Acknowledgement (4) Block: 0 Frame 4 Src Addr: 10.110.53.1 Dst Addr: 10.110.53.2 Trivial File Transfer Protocol Opcode: Data Packet (3) Block: 1 Data (1432 bytes) LTSP TFTP Exchange

  20. Frame 1 Message type: Boot Request (1) Client hardware address: 00:50:ba:d3:a0:ab Option 53: DHCP Message Type = DHCP Discover Option 55: Parameter Request List 1 = Subnet Mask 28 = Broadcast Address 3 = Router 15 = Domain Name 6 = Domain Name Server 12 = Host Name 17 = Root Path Frame 2 Message type: Boot Reply (2) Your (client) IP address: 10.110.53.2 Next server IP address: 10.110.53.1 Client hardware address: 00:50:ba:d3:a0:ab Boot file name: /lts/vmlinuz-2.4.19-ltsp-1 Option 53: DHCP Message Type = DHCP Offer Option 54: Server Identifier = 10.110.53.1 Option 51: IP Address Lease Time = 6 hours Option 1: Subnet Mask = 255.255.255.0 Option 28: Broadcast Address = 10.110.53.255 Option 3: Router = 10.110.53.254 Option 15: Domain Name = "ltsp.local" Option 6: Domain Name Server = 10.110.53.1 Option 12: Host Name = "ws001" Option 17: Root Path = "10.110.53.1:/opt/ltsp/i386" LTSP DHCP Exchange

  21. Frame 3 Message type: Boot Request (1) Client hardware address: 00:50:ba:d3:a0:ab Magic cookie: (OK) Option 53: DHCP Message Type = DHCP Request Option 54: Server Identifier = 10.110.53.1 Option 50: Requested IP Address = 10.110.53.2 Option 55: Parameter Request List 1 = Subnet Mask 28 = Broadcast Address 3 = Router 15 = Domain Name 6 = Domain Name Server 12 = Host Name 17 = Root Path Frame 4 Message type: Boot Reply (2) Your (client) IP address: 10.110.53.2 Next server IP address: 10.110.53.1 Client hardware address: 00:50:ba:d3:a0:ab Boot file name: /lts/vmlinuz-2.4.19-ltsp-1 Option 53: DHCP Message Type = DHCP ACK Option 54: Server Identifier = 10.110.53.1 Option 51: IP Address Lease Time = 6 hours Option 1: Subnet Mask = 255.255.255.0 Option 28: Broadcast Address = 10.110.53.255 Option 3: Router = 10.110.53.254 Option 15: Domain Name = "ltsp.local" Option 6: Domain Name Server = 10.110.53.1 Option 12: Host Name = "ws001" Option 17: Root Path = "10.110.53.1:/opt/ltsp/i386“ LTSP DHCP Exchange

  22. Practical Application of LTSP • 402 OS Scripting • Only terminal mode is needed • All users use NFS • No prelab • Access anywhere

  23. Windows Terminal Server • Comes standard with Windows Server beginning with Windows 2000 Server • Came out of NT4 Terminal Server Edition • Uses RDP Protocol • Can be used for administration or application deployment • Requires licensing for application deployment • Windows XP was not the first to have terminal services

  24. Windows 2003 RDP 5.2 • Can redirect sound, serial ports, and printers • Remote Users group controls access • Group Policy • RC4 128-bit stream cipher • Disconnection vs. Logoff • Terminal Services Session Directory • Requires Enterprise Edition • Client is installed in Windows XP and later

  25. Licensing • Windows Server License • Windows Client Access License • Windows Terminal Services Client Access License • Terminal Services Licensing Server

  26. Limitations of Windows Terminal Services • No easy way of • Pushing just applications • Building web portals • Unsupported clients available

  27. Why Citrix MetaFrame? • Application Server • Distributed Management • Centralized Resources • 95% Fortune 500 • 95% European FT 100 • 100% Fortune 100 • Over 120,000 Organizations

  28. Current Flavors of Citrix • XPs - Standard • XPa - Access • XPe - Enterprise

  29. XPs • Ideal for small environments • Includes ICA protocol (Independent Computing Architecture), client platform support, network protocol support, seamless desktop • Does not including load balancing features

  30. XPa • For medium sized businesses • Includes all of XPs features • Includes load management support

  31. XPe • Enterprise version • Includes all of XPa features • Installation manager, resource manager, and network manager

  32. Drawbacks • Laptop management • Selling to Management • Poor application design • High initial cost if client server model is already implemented • 3D Applications/Specific hardware needs • Licensing model

  33. Licensing • Windows Server License • Windows Client Access License • Windows Terminal Services Client Access License • Terminal Services Licensing Server • Citrix Server License • Citrix Connection License

  34. Metaframe • “Any client device, any network connection, any network protocol, seamless desktop integration”

  35. Metaframe • “Any client device…” • Any application can be run on any OS • Windows CE Devices, Windows 16-bit/32-bit, UNIX, Mac, Java, OS/2 Warp, EPOC/Symbol, DOS 16-bit/32-bit • Example: MS-DOS 5.0 running Microsoft Office 2000

  36. Metaframe • “Any network connection…” • Little client side performance impact • Optimized for connections as low as 14.4Kbps • Mouse clicks and keyboard strokes from client to server • Screen updates sent from server to client

  37. Metaframe • “Any network protocol…” • Works at Presentation level of the OSI model • TCP/IP, IPX, SPX, Net BIOS, NetBEUI, PPP, Async, ISDN, Frame Relay, ATM, and any other existing or developing protocols.

  38. Metaframe • “Desktop integration.” • Application appears local to users • Limit questions posed to IT staff • No retraining for how users run applications

  39. Metaframe • Application launching and embedding • Launching allows users to open a program from a web browser into a new window • Embedding opens the application right in the web browser

  40. Components of the ICA Packet

  41. ICA Packet • Reliable: • is used in connectionless protocols such as IPX and UDP to provide reliable, error-free delivery. • Encryption: • is used as the preamble for managing any packets that contain encrypted data. • Compression: • is used as the preamble for managing any packets that contain compressed data.

  42. ICA Packet • Command byte: • Is the only required ICA command byte. This is the beginning of the base ICA protocol packet. • Command data: • Contains optional data bytes associated with the specific command. The length of the data is dependent on the command.

  43. Deployment in Windows 2000 • Problems with deployment based on computers • All users must use the same application suite • Same user must login on that terminal all the time • Problems with installs based on users • What happens if that user only logs into that computer once?

  44. Deployment in Citrix • Programs are installed once on the server and then deployed for a user or group of users • No additional data is stored on the client • Hardware can be easily attached and used with the Citrix server • Installation Manager used for pushing around applications in the farm

  45. Disaster Recovery • All the data and applications are held centrally • Servers within a farm can be divided across physical boundaries • Clients become more meaningless and can be easily swapped with cheap replacements

  46. Storage Solutions • Servers talk directly to the storage unit decreasing latency in file transactions • Storage is consolidated in once place • Can be used to prohibit the user from saving files to their local computers • Can be used to transfer files to and from the server

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