ATM technology (14)
Classical IP-Over-ATM (IPOA RFC 1577)
ATM is a connection-oriented protocol, which means that connection must be established between two communicating entities before data transfer can begin. IP is inherently connectionless. There are 2 ways to run transparently IP traffic over ATM: Classical IP and LAN emulation
The term "classical" indicates that the ATM network has the same properties as existing legacy LANs.
SVC management is performed via UNI specification, which defines signaling: Q.93B (UNI3.0), Q.2931 (UNI3.1).
Once a Classical IP connection has been established, IP datagrams are encapsulated using IEEE 802.2 LLC/SNAP and are segmented into ATM cells using AAL5.
There is no support for broadcast and multicast in a Classical IP environment. The Classical network is divided into LISs (Logical IP Subnets).
Each LIS must have only on ATM ARP server configured on a switch or a host ARP server is responsible for resolving an IP addresses into ATM addresses.