Diese Präsentation wurde erfolgreich gemeldet.
Wir verwenden Ihre LinkedIn Profilangaben und Informationen zu Ihren Aktivitäten, um Anzeigen zu personalisieren und Ihnen relevantere Inhalte anzuzeigen. Sie können Ihre Anzeigeneinstellungen jederzeit ändern.

Bonjour protocol

6.855 Aufrufe

Veröffentlicht am

This presentation describes the concept of zero configuration by explaining the bonjour protocol.

Veröffentlicht in: Technologie
  • Als Erste(r) kommentieren

Bonjour protocol

  1. 1. BONJOUR Prepared for Prof. Kaewon Choi By Salah Amean Ahmmed
  2. 2. INTRODUCTION  IP like electricity or water  Just plug and it work  Bonjour is truly revolutionary,  it is one of the things that is going to have the largest impact on application designing over the next couple of years.
  3. 3. BACKGROUND  Bonjour is Apple’s implementation of a suite of zero-configuration networking protocols.  Bonjour is designed to make network configuration easier for users. For example, Bonjour lets you connect a printer to your network without the need to assign it a specific IP address or manually enter that address into each computer  With zero-configuration networking,  Nearby computers can discover its (printers) existence and automatically determine the printer’s IP address  They can automatically discover the new address in the future even when changes happen
  4. 4. BACKGROUND  Apps can also leverage Bonjour to automatically detect other instances of the app (or other services) on the network.  For example, two users running an iOS photo sharing app could share photos over  Bluetooth personal area network without the need to manually configure IP addresses on either device
  5. 5. WHY BONJOUR?  The transition from platform-specific protocols(AppleTalk) to IP happened over the past two decades  Currently computers and other network devices all use TCP/IP for communication.  In that transition, however, one piece of functionality was lost  the ability to add devices to a local network and then connect to those devices from computers and other devices on the network, all with little or no configuration.
  6. 6. CONCEPT  For IP to work, devices need to be assigned addresses either manually or dynamically(DHCP).  A dynamically assigned address can change,  Without Bonjour,  Printers and other devices had to be manually configured with a static address so that computers on the network could reach them. DNS server has to be configured so that computer users didn’t have to connect to the printer by IP address.  Thus, a seemingly minor task required significant configuration.  Sometimes it isn’t practical to have complicated configuration for minor tasks such as printing a paper
  7. 7. CAPABILITY OF BONJOUR  Without wasting people time to get configuration done, people should be to be able to  plug in the printer,  plug two laptops together, or  look for a file server or game server on the local network  To support this, people need a simple and reliable way to configure and browse for services over IP networks.  User want to discover available services and  Choose one from a list, instead of having to know each service’s name or IP address in advance.  It is in everyone’s interest for IP to have this capability
  8. 8. ZERO CONFIGURATION: AN EXAMPLE  In step 1, you open up your laptop in your neighbor’s house, and the laptop either  Obtains an address from DHCP server in the router or,  In the absence of a DHCP server, assigns itself an available local address  In step 2, the network is queried for available printers so that  when you open the Print dialog, your neighbor’s printer is listed  In step 3, you turn on music sharing on your computer, and your neighbor’s computer sees it and connects.
  9. 9. ZERO CONFIGURATION: AN EXAMPLE
  10. 10. ZERO CONFIGURATION: AN EXAMPLE
  11. 11. WHAT IS ZEROCONF NETWORK?  No external supporting infrastructure  No manual configuration  No (conventional)DHCP Server  No conventional DNS server  Limited Network Scope  Not too many users  Not too many hosts;  Simply by connecting two laptops using Ethernet cable
  12. 12. THREE LEGS OF BONJOUR  Addressing : address is need to identify host on the network  Naming: using names instead of the IP address  Browsing: we need to discover what is in the network.
  13. 13. ADDRESSING  Self-Assigned Link-Local Addressing  Pick random address in 169.254/16  Claim this address by ARP  ARP to see if anyone else is using it  if someone else is using it, try again  ongoing conflict checking  Http://www.zeroconf.org/  One of the important issues regarding this sort of addressing is that they are meant for local usage only typically a small LAN or a single LAN segment  For example when we print a document from host A to a host B on the local network, then this addressing scheme is sufficient
  14. 14. IPV4 LINK-LOCAL AVAILABILITY  Self-Assigned IPv4 Link-local Addressing  first appeared in  Mac OS8.5,1998  Windows 98, 1998  Mac OS X 10.0  IPv6 already has link-local addressing  This is not to compete with it but to encourage apps to support IPv6  But low cost devices that has no support for IPv6  Major operating systems supports local link addressing  Hardware manufacturers should implement link-local addressing on their devices to obtain the full benefit of Bonjour.
  15. 15. ADDRESSING WITH ZEROCONF  Device that supports link-local addressing benefits from this feature automatically.  When your host computer encounters a local network,  it finds an unused local address and  adopts it.  No action on your part is required.
  16. 16. NAMING  Multicast DNS is the proposed solution to the translation of name-to-address on local networks  Because these DNS queries are sent to a multicast address,  no single DNS server with global knowledge is required to answer the queries.  Each service or device can provide its own DNS capability  when it sees a query for its own name,  it provides a DNS response with its own address.
  17. 17. NAMING AND RESPONDER  Responder handles mDNS queries for any network service on the device  This daemon takes charge of interpreting mDNS queries and multicast messages  Automatically advertises the availability of your service  so that any queries for your name are directed to the correct IP address and port number automatically.
  18. 18. NAMING  Uniqueness of names is essential for name-to-address to work properly  Names in bonjour have local significance only  Pick desired name in ".local."subdomain  Issue Query to see if anyone else is using it  if someone is else already using it, pick another  ongoing conflict checking
  19. 19. NAMING EXAMPLE  A printer with the default name XYZ-LaserPrinter. local to Local network.  XYZ-LaserPrinter.local, then XYZ-LaserPrinter- 2.local,  XYZ-LaserPrinter-3.local is unused,thus becomes the name  Bonjour renames automatically
  20. 20. BROWSING  “what we want to do?” is to just browse what is inside the network rather just type is in the browser some numbers or names  Long list of attempts allows automatic detection of devices/services on networks  RLP (resource location protocol)  SDP (Service discovery protocol)  SSDP (Simple service discovery protocol)  SDS Service discovery services
  21. 21. DEVICE-CENTRIC VS. SERVICE CENTRIC  In device centric  A client queries to the server, and checks what is available on the server  Server responds with list of running service( HTTP, ftp, etc.)  Digging inside the server for some relevant information  Decides what services to use  The Response:  May not be exactly what the user needs  Cause a lot of unneeded network traffic
  22. 22. DEVICE-CENTRIC VS. SERVICE CENTRIC  In service centric:  It makes more sense to query for “What print services are available?” than  “what services are you running” then go though list of available services  In this scheme, a single query produce only relevant replies  Services are not tied to specific IP addresses or even host names (e.g., load-balancing situation)  Queries are made according to the type of service needed, not the hosts providing them
  23. 23. SERVICE DISCOVERY  Service discovery in Bonjour is accomplished by “browsing.”  An mDNS query is sent out for a given service, type and domain  Any matching services reply with their names  The result is a list of available services to choose from.
  24. 24. BONJOUR SERVICE DISCOVERY  Bonjour takes the service-oriented approach. Queries are made according to the type of service needed, not the hosts providing them.  Applications store service instance names, not addresses, so if the IP address, port number, or even host name has changed, the application can still connect.  User’s browsing experience is made more useful and trouble-free.
  25. 25. SERVICE DISCOVERY ADVANTAGES  Allows applications to find all available instances of a particular type of service and  To maintain a list of named services and port numbers  So with changes, effect won’t hurt
  26. 26. SERVICE DISCOVERY EXAMPLE
  27. 27. PUBLISHING A SERVICE
  28. 28. PUBLISHING A SERVICE-CONT’
  29. 29. ADVERTISING SERVICES  Applications provide a service name and port  follows same DNS specific to general model  ServiceName._ServiceType._TransportProtocolN ame.Domain  ServiceName is human readable descriptive name  Maximum of 63byte  All characters are allowed  HP officeJet8500._ipp._tcp.local.  service name is HP officeJet8500  services type(internet printing protocol) is ipp  Transport Protocol is tcp  Domain is .local
  30. 30. CHALLENGES
  31. 31. SOLUTION  Caching  mDNSresponder takes charge of caching,  Some requests are kept to the time of need  Suppression of duplicate responses  Back-off
  32. 32. CHALLENGES
  33. 33. BONJOUR BONJOUR GATEWAY DEMO  http://www.youtube.com/watch?v=i8vNlqV67uA
  34. 34. DEMO LAB310
  35. 35. REFERENCES  https://developer.apple.com/library/mac/documentation/cocoa/conc eptual/NetServices/Articles/NetServicesArchitecture.html  http://www.zeroconf.org/QDIPv4LL.html  http://www.youtube.com/watch?v=pdbTyxYmF84  http://www.ietf.org/rfc/rfc3927.txt  http://www.aerohive.com/solutions/technology-behind-solution/ bonjour-gateway  http://blogs.enterasys.com/apple-bonjour-devices-in-the-enterprise- part-1/  http://en.wikipedia.org/wiki/Zero-configuration_networking

×