User guide

CobraNet Programmer’s Reference

Network Stack

3. Network Stack

Figure 5. CobraNet Network Stack

3.1 CobraNet Audio

This includes transmission and reception of audio data packets and reservation requests,

implementation of conductor arbitration, and the ability to serve in either conductor or

performer roles. CobraNet audio is a self-contained service that spans from Logical Link

(2) to Application (7) layers.

3.2 Serial Bridge

This service provides bridging of asynchronous serial streams over the Ethernet network.

This self-contained service spans from the logical link to the Application layer. The serial

bridge service is discussed in Section 2.1 "Serial Bridge" on page 12.

3.3 Packet Bridge

This service simply allows the CobraNet interface to operate as an Ethernet controller for

a connected host. This service works at the logical link layer and provides access to the

network without providing any actual network services. The packet bridge feature is

discussed in Section 2.2 "Packet Bridge" on page 13.

3.4 BOOTP

The boot protocol (BOOTP) is supported as specified in RFCs 951 and 1542. Network

clients use BOOTP to receive an IP address from a BOOTP server.

Clients needing an IP address will broadcast a BOOTP request packet. A BOOTP server

on the network will respond with a BOOTP response containing the preferred IP address

for the client to use. Use of BOOTP simplifies the error-prone task of assigning unique IP

addresses to devices on a large network. BOOTP is carried via UDP/IP and, as such, is

able to pass through properly configured routers.

BOOTP requests are transmitted by the CobraNet interface on a randomized schedule as

recommended in the RFCs. Requests are sent out frequently at startup and then taper

CobraNet ServicesInternet Protocol Suite

Fast Ethernet Interface

802.3 Ethernet

IP RARP ARP

UDP

BOOTP SNMP TFTP

ICMP

Packet

Bridge

CobraNet

Audio

Serial

Bridge

Physica

Logical Link

Network

Transport

Applicatio