User`s manual

DataNET Hub Operation, Continued
DataNET Switching
DataNET switching operates by dynamically and automatically learning
the topology of the network (i.e., which MAC/IP addresses are reachable
through which paths) as Ethernet frames are forwarded through the
network. The DataNET hubs require no static initialization of network
data in order to perform their switching function.
Each DNH can learn as many as 1200 IP addresses. This allows the hub
to accommodate up to 1000 instruments (analyzers, etc.), and still be
able to switch frames from another 200 devices (workstations, etc.).
DataNET switching accommodates any Ethernet-encapsulated protocol.
The hub will also “snoop” IP data grams (RFC 894) and ARP messages
(RFC 826) to learn the locations of all devices using IP.
Definitions
• MAC Address (Media Access Control). The “built-in” hardware
address of a device connected to a shared media.
• IP Address is a 32-bit address defined by the Internet Protocol. It is
usually represented in dotted decimal notation. Present address is
127.236.032.239
Transparency
DataNET hubs operate as layer 2 Ethernet bridges. That is, hubs will
forward frames among connected Ethernet segments and DataNET
devices regardless of the upper layer protocols carried in those frames.
In the absence of hardware failures or network overload, the hub
software will deliver each Ethernet frame to its intended destination (all
stations in the case of Ethernet broadcasts) in order and without
duplication. In normal operation, the network may deliver frames to
additional destinations (i.e., to stations whose MAC addresses do not
match the frames’ destination address). End devices must be prepared
to receive and ignore frames whose destination addresses do not match
their own MAC addresses.
2000585-001 Introduction • 5