Sun Microsystems 3U manual Classical Internet Protocol, ATM Address Registration Daemon ilmid

ATM Address Registration Daemon (ilmid)

Address registration with a switch is controlled by ilmid. When an ATM interface is brought up at boot time, ilmid is also started. ilmid then begins an exchange of messages with the switch: relaying local address information (the seven-octet ESI and selector) to the switch and receiving the 13-octet network prefix information from the switch.

The default local address that is registered with the switch at boot time consists of the network prefix provided by the switch, the MAC address assigned to the local interface, and the default selector for that interface (usually 0). Additional addresses are registered in two different ways. aarsetup(1M) and lanesetup(1M) register additional local addresses that may appear in aarconfig(4) and laneconfig(4), respectively. You can also use atmreg(1M) to register addresses, unregister addresses, and check the status of any address.

Classical Internet Protocol

For ATM to work transparently under IP, an IP address must be resolved to an ATM address and a connection to that destination must be established. Classical IP does this via a database of IP/ATM address pairs that is either provided by an ATM ARP server that is accessible to all hosts on the subnet, or is maintained locally in each host.

ATM Address Resolution

Traditional TCP/IP and UDP/IP applications use IP addresses for communicating to a destination. For these applications to run like traditional applications, IP addresses need to be resolved into ATM addresses. The ATM address then signals to establish an ATM connection to the destination. An ATM connection in turn is represented by a VPI/VCI. The host must use this returned VPI/VCI to send packets to the destination that represents the ATM connection.

ATM address resolution, also called ATM ARP, follows RFC 1577, the classic draft that describes the ATM ARP process.

RFC 1577 assumes the existence of an ATM ARP server on every subnet. Every client on the subnet communicates with the ATM ARP server to derive the destination’s ATM address from its IP address. The ATM ARP server holds the IP-to-ATM address information for all hosts in the ATM subnet. It is likely that initial ATM configurations will not rely on dynamic ATM address resolution because it requires the presence of an ATM ARP server on every subnet. Also, there are no specified

Chapter 7 Classical IP and LAN Emulation Protocols 67