Cabletron Systems TSX-1620 Changing Source Routing Port Parameters

Using the TSX-1620 Bridge View

STE Span Mode

The Spanning Tree Explorer Span Mode determines how a bridge port behaves

when it receives an STE packet (also known as Single Route Explorer packet).

Possible STE Span modes are disabled, forced, and auto-span, as described earlier

in this section.

Changing Source Routing Port Parameters

To change a port’s Hop Count, Local Segment, Bridge Number, or Target

Segment:

1. In the Source Routing Conﬁguration window, use the scroll list to display the

physical TSX-1620 port for which you want to change values.

2. Select a port by clicking mouse button 1 on the port you want to change. You

can only select one port at a time. The port’s index number and Source

Routing parameters appear in the boxes below the list.

3. Highlight and edit the Hop Count, Local Segment, Bridge Number, and

Target Segment boxes as required.

4. Once you have made all of your edits, click on the Apply button.

To change a port’s Largest Frame or STE Span Mode:

1. In the Source Routing Conﬁguration window, use the scroll list to display the

physical TSX-1620 port you want to change.

2. Click mouse button 1 on the port you want to change (you can only select one

port at a time). The port’s Source Routing parameters appear in the boxes

below the list.

3. Click on the Largest Frame or STE Span Mode button and then drag to the

appropriate menu choice. The selected value appears on the button.

4. Once you have made all of your choices, click on the Apply button.

NOTES

A Source Route-capable bridge has the ability to embed Largest Frame size information

into the explorer packets. If there are multiple bridge hops from one end node to another,

this allows the end stations to realize the maximum frame size limits for any network

segment in the path between them, and adjust their Mtu size accordingly.

If there are multiple hops from one end node to another, consider the lowest Largest Frame

Size of all network segments and bridges in the path when setting the Largest Frame Size.

It is possible that an older bridge may support a lower maximum frame size; subsequently

the stations would have to reduce their Mtu size in order to communicate over it. Largest

Frame size is different for 4 and 16 Mbps Token Rings (4,500 bytes and 18,000 bytes,

respectively), and Ethernet network segments have a maximum frame size of 1,500 bytes.