Hardware manual
Table Of Contents
- Cover Page
- Contents
- About this guide
- Safety Instructions and safety warnings
- Before you start
- Introduction to NION
- Setting up the NION
- Introduction
- Configuration
- Updating the firmware
- Using the front panel
- Using the web interface
- Using XDAB clusters with VLANs and CobraNet
- Introduction
- Important concepts
- Use cases
- Scenario 1 - Basic network
- Scenario 2 - Network using VLAN
- Scenario 3 - Network with VLAN and analog interconnects
- Scenario 4 - Network with VLAN and digital interconnects
- Scenario 5 - Network with an XDAB cluster
- Scenario 6 - Network with VLAN and XDAB
- Scenario 7 - Network with VLAN and XDAB
- Scenario 8 - Network with VLAN and two XDAB clusters
- Scenario 9 - Network with VLAN and three XDAB clusters
- Setting conductor and XDAB priority in NWare
- Further examples
- Troubleshooting
- Connector ports
- Technical specifications
- Reference Information
- Warranty statement
Appendix A - Troubleshooting
68 Version 1.6.2a.0 May 17, 2011
To put it in audio terms, a network loop is analogous to an audio feedback loop. The screech
one hears in audio feedback is due to continuous positive reinforcement of the signal. A
network loop causes a similar positive reinforcement of the data. Data packets are replicated
and increase in quantity with each hop through a switch until all available network bandwidth
is consumed.
Many Ethernet switches contain some variant of the Spanning Tree Protocol (STP, RSTP or
MSTP) that detects and logically removes loops. Standard STP should not allow a connection
to be made until it is sure that the connection will not cause a loop. MSTP and RSTP can
behave a little differently. If a new connection is made through a port that the protocol
previously considered to be an edge port. (i.e. it cannot be connected to another switch), then
the port will be immediately enabled. If this connection is such that it can create a loop, then a
data storm can occur. Explicitly setting ports within an RSTP/MSTP managed switch to be
edge or bridge ports, per their usage, may alleviate this problem.
Commonly used fault tolerant techniques for CobraNet networks
Intentional creation of a loop, with reliance on STP to remove it, in order to create a spare
connection that will be automatically activated when a link in the network goes down.