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7.3 Network Services

7.3.1 ILMI

Embedded software provides an ILMI 4.0 implementation which handles address registration (switch to

end device) and notification (end device to switch) as well as auto-configuration. ILMI uses SNMP over

AAL-5 for transport.

7.3.2 UNI Signaling

Stackware includes support for standard ATM UNI signaling standards, including UNI 3.1.

7.3.3 RIP1/RIP2 IP Router

IP router software provides implementations of RIP1 and RIP2. The IP router is an IPv4 router. Support

for new station discovery is provided.

7.4 TCP/IP Socket

7.4.1 TCP

Transport Control Protocol (TCP) is accessed using a standard socket interface to allow easy integration

of existing Layer 3 and higher software into the basic protocol stack.

7.4.2 IP

Internal protocol: IP and IP routing are both part of the network layer (layer 3). IP is actually responsible

for delivering packets for which the router defines the direction.

7.4.3 DHCP RFC 2131, 2132

Dynamic Host Control Protocol (DHCP) provides both client & server functions. The client is typically used

to obtain an IP address from an ISP. The DHCP server is used to assign local IP client devices with des-

ignated IP addresses. The server lends addresses for a limited time. NAT registers local terminal IP ad-

dresses and maintains a translation table to allow sending and receiving data on the public network by

sharing only the residential gateway assigned public IP address.

7.4.4 NAT: RFC1631, 2663

The Network Address Translator (NAT) implements Network and Port Address Translation (NAT/PAT).

NAT allows a single public IP address on the WAN side to be shared among many devices on the LAN

side. Combined with a DHCP server local devices are assigned a private address, hidden to the public

internet and changed frequently. The combination of DHCP and NAT provides a powerful isolation barrier

to external assault. NAT PAT features a number of AGL.

7.5 ATM Encapsulation and spanning-tree

RFC 1483/2684 provides a simple robust method of connecting end stations over an ATM network. User

data in the form of Ethernet packets are encapsulated into AAL-5 PDUs for transport over ATM. RFC

1483/2684 provides no AAA function (authentication, authorization & accounting).

7.5.1 Spanning-tree bridge (802.1d)

Bridge module provides a transparent bridge between two physically disjoint networks with spanning-tree

option. The spanning-tree algorithm handles redundancy and also increases robustness. It provides high

performance as well as flexibility to group interfaces for example to bridge the WAN only to LAN interfaces

but not to other WAN interfaces.

The ATM driver passes data between application software tasks on the processor and a physical AAL5

hardware block.