Purpose
But what if your are starting to have bandwidth concerns or simply want to segregate the LAN traffic by department or location? The 8239 enables you to segment a single LAN into multiple LANs while maintaining stack management of all the hubs that make up the stack.
Description
In the 8239 stack, segmentation is provided at the hub level, by wrapping a given hub in or out of the default single segment. This isolates the Data Path of one or more hubs from the Data Paths of the other hubs in the stack. All 16 ports in the hub, including additional ports if the optional feature card is installed, are treated as a single entity or hub when segmenting a ring. Every hub in a stack must be assigned to a segment. The factory default has all hubs assigned to a single segment. If, for example, a stack consisted of four hubs (any combination of models), it could be segmented into a maximum of four segments. If a stack consisted of the maximum eight hubs, from one to eight segments could be created. Hubs in the same segment must be adjacent to each other in ring order when you connect them with the intra-stack cables. Management of the stack is maintained because the Control Path of the stack is not affected when the Data Path is altered because of segmentation. If network management functions, like Ring-In/Ring-Out or RMON, are important for a particular segment, that segment must consist of at least one Model 1.
Prerequisite
The 8239 ships with its Operational Code already installed. Users are encouraged to always check the 8239 Home Page to determine the most recent level. For segmentation purposes, the Operational Code must be Version 2.0 or higher.
Network Management Functions
The 8239 offers an impressive array of network management functions as well as stack management capability. Functions like Ring-In/Ring-Out, RMON, 802.5, Surrogate MIB for media management, etc. are all programmed into the Model 1. Accordingly, a Model 1 must be included in each segment where this activity is required.
Stack Management Functions
Because the Control Path is not affected by segmentation, normal stack management activities and functions are not impacted by segmentation. These would include but are not limited to:
- Beacon Recovery
- Address-to-Port Mapping
- Port Security
- Operational code downloads
- EIA-232 Out-Of-Band port
- Ring-In/Ring-Out
- Functions provided by network management applications
Network Management Applications
The Nways Management applications for Windows NT, AIX, and HP-UX recognize 8239 segmentation.
The screen image will graphically show the hubs in a stack and their associated segments,
from the default single segment to the maximum potential of eight segments. The usual picture of the hub or hubs
will be displayed with an oval ring on the right side of the screen showing the delineation of segments.
Example of Segmentation
Following are three examples of segmentation, taken from the 8239 Setup and User's Guide. Click on the links below to view the figures. Figures will appear in a new browser window.
Figure 1: Single Segment
Figure 1 depicts a single segment with six units with a single Model 1 in the initial stage, the default configuration. Note that all units are attached to the stack ring creating a single segment
Figure 2: Two Segments Figure 2 shows four segments; two segments, each with only one hub; two segments, each with two hubs. Only segment one has a Model 1 and therefore has network management access.
Figure 3: Three segments Figure 3 contains three segments and six hubs; each segment can be managed because a Model 1 is included in each.
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