User`s manual

Overview, Continued

DataNET Hub

Hierarchy

A network of DataNET hubs forms a tree-like hierarchy. A DNH may

connect to as many as eight “down-stream” devices (Maxum Analyzers

or Advance Hub Uplink port). Each down-stream DNH, in turn, connects

to another eight, and so on. No architectural limit is placed on the depth

of the DataNET hub hierarchy. In practice, propagation time

considerations and hub loading should allow hierarchies at least six or

seven layers deep without incurring excessive timing delays.

Figure 1-2: DataNET Hub

Hierarchy

DataNET hub

DataNET hub DataNET hub

DataNET hub

Ethernet

Ethernet Bridging

Figure 1-3 illustrates two separate trees of DataNET hubs that share an

Ethernet segment.

A hub can also connect to-and-from an Ethernet device or an Ethernet

compatible Advance Network Gateway (ANG) unit or to and from a non-

redundant Ethernet connection. A tree of DataNET hubs can function as

an Ethernet bridge, transparently connecting all the Ethernet segments

that are attached at any point on the hierarchy. The DataNET hub

software does not implement any software protocols (e.g. IEEE 802.1

spanning tree) to prevent routing loops. Thus, each tree of DataNET

hubs may connect to any Ethernet segment at exactly one point. Multiple

DataNET trees may share Ethernet links.

DataNET hub

Ethernet

DataNET hub

Ethernet

Figure 1-3: Ethernet

Bridging

2000585-001 Introduction • 3