1 / 14

Stateless Autoconfiguration

Stateless Autoconfiguration. Why does this matter?. Manual configuration of individual machines before connecting them to the network should not be required. Address autoconfiguration assumes that each interface can provide a unique identifier for that interface (i.e., an "interface token")

edwardjones
Download Presentation

Stateless Autoconfiguration

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Stateless Autoconfiguration

  2. Why does this matter? • Manual configuration of individual machines before connecting them to the network should not be required. • Address autoconfiguration assumes that each interface can provide a unique identifier for that interface (i.e., an "interface token") • Plug-and-play communication is achieved through the use of link-local addresses • Small sites should not need stateful servers • A large site with multiple networks and routers should not require the presence of a stateful address configuration server. • Address configuration should facilitate the graceful renumbering of a site's machines

  3. Stateless Autoconfiguration Generate a link local address Verify this tentative address Is ok. Use a neighbor solicitation with the tentative address as the target. ICMP type 135 If the address is in use a neighbor advertisement Message will be returned. ICMP type 136 If no response Assign the address to the Interface. At this point the Node can communicate On-link. Fail and go to manual Configuration or choose A different interface token

  4. Stateless Autoconfiguration Assign address to Interface. Node joins the All Routers Multicast group. FF02::1 Sends out a router Solicitation message to That group. ICMP type 133 Router responds with a Router advertisement. ICMP type 134

  5. Stateless Autoconfiguration Look at the “managed address configuration" flag If M=1 stop and Do statefull config. If M= 0 proceed with Stateless configuration If O= 1 use statefull Configuration for other information Look at "other stateful configuration" flag If O = 0 finish

  6. Router Solicitation Type = 133 Code = 0 Checksum Reserved Possible options: Source link layer Address

  7. Router Advertisement Type = 134 Code = 0 Checksum Cur Hop Limit M O Reserved Router Lifetime Reachable TIme Retransmission Timer • Possible Options: • -Source Link Layer address • MTU • Prefix Information

  8. Neighbor Solicitation Type = 135 Code = 0 Checksum Reserved Target Address Possible Option: Source Link Layer Address

  9. Neighbor Advertisment Type = 136 Code = 0 Checksum R S O Reserved Target Address Possible Option: Source Link Layer Address

  10. Prefix Option type length Prefix length L A Reserved Valid Lifetime Preferred Lifetime reserved Prefix list

  11. Router Solicitation OptionsPrefix Information • This should include all prefixes the router is aware of • Flag bits: • On-link = 1 • Prefix is specific to the local site • Autonomous Configuration bit = 1 • Use the prefix to create an autonomous address

  12. Router Solicitation OptionsPrefix Information • Valid Lifetime • 32-bit unsigned integer. The length of time in seconds before an address is invalidated. • Preferred Lifetime • 32-bit unsigned integer. The length of time in seconds before an address is depreciated.

  13. Stateless autoconfig • Routers are to send out router advertisements at regular intervals at the all hosts address. • This should update lifetimes. • Note that stateless autoconfig will only configure addresses. • It will not do all the host configuration you may well want to do.

  14. Stateful configuration • When you do not wish to have stateless configuration done you will need to provide a configuration server (DHCP most likely) to provide configuration information to the hosts as they come up.

More Related