EDS-508A/505A Series User’s Manual
Featured Functions
3-40
Setting
Description
Factory Default
Tail Port
Select any port of the EDS to be the tail
port.
EDS-505A: port 4
EDS-508A: port 7
Member Port
Select any port of the EDS to be the
member port.
EDS-505A: port 5
EDS-508A: port 8
The STP/RSTP Concept
Spanning Tree Protocol (STP) was designed to help reduce link failures in a network, and provide
protection from loops. Networks that have a complicated architecture are prone to broadcast
storms caused by unintended loops in the network. The EDS’s STP feature is disabled by default.
To be completely effective, you must enable RSTP/STP on every EDS connected to your network.
Rapid Spanning Tree Protocol (RSTP) implements the Spanning Tree Algorithm and Protocol
defined by IEEE Std 802.1w-2001. RSTP provides the following benefits:
The topology of a bridged network will be determined much more quickly compared to STP.
RSTP is backward compatible with STP, making it relatively easy to deploy. For example:
Defaults to sending 802.1D style BPDUs if packets with this format are received.
STP (802.1D) and RSTP (802.1w) can operate on different ports of the same EDS. This
feature is particularly helpful when the EDS’s ports connect to older equipment, such as
legacy switches.
You get essentially the same functionality with RSTP and STP. To see how the two systems differ,
see the
Differences between RSTP and STP
section in this chapter.
NOTE
The STP protocol is part of the IEEE Std 802.1D, 1998 Edition bridge specification. The
following explanation uses bridge instead of switch.
What is STP?