Describe how Mac OS X is designed to support networking without requiring configuration.
2.
What are the three key networking issues addressed by Bonjour?
3.
What is IPv4 link-local addressing? Describe its use in Bonjour?
4.
What is multicast DNS? Describe its use in Bonjour?
5.
What is DNS Service Discovery? Describe its use in Bonjour.
6.
What is the difference between a computer name and a Bonjour name?
Answers
1.
Mac OS X includes support for work based on the IETF's Zeroconf Working Group for Zero Network IP Configuration. The Apple implementation is called Bonjour. Bonjour configures Mac OS X for network support without requiring the user or network administrator to do any configuration.
2.
IP address assignment, naming, and service discovery (browsing)
3.
Link-local addressing allows a computer to self-assign an IP address when the computer is configured to use DHCP but no DHCP server is available. With link-local addressing, a computer randomly selects an address from the 169.254/16 range and checks to make sure no other device is using this address throughout the lifetime of the link. This is referred to as link-local since the address is valid only on the local link, or subnet.
4.
Every Bonjour host contains a small DNS responder. This DNS responder can respond with the service's IP address when it sees another client requesting a lookup of its host name. Whereas a typical DNS lookup is pointed at a single DNS server, Bonjour allows multicast DNS requests that are seen by all Bonjour DNS responders running on the local link. The DNS responder ensures name-to-address lookups happen, despite not having a centrally managed DNS server, as well as when IP addresses change over time.
5.
DNS Service Discovery relies on the DNS capability of doing a key-value lookup. Whereas DNS traditionally uses a domain name key to lookup an IP address value, DNS Service Discovery extends the meaning of key to include a service type and the value to be the service type's name. DNS supports multiple responses, which allows someone looking for a specific type of service to see all services of that type on the local subnet.
6.
The Bonjour name is your link-local multicast DNS host name, which you can use with command-line tools like FTP, ssh, Telnet, and ping, as well as Mac OS X Windows File Sharing. The computer name is the default name that Bonjour uses for DNS Service Discovery.
