User`s manual
NPort S8000 Series Switch Featured Functions
6-14
Head Port Select any port of the S8000 series to be the head port. S8000 series: port 4
Member Port Select any port of the S8000 series to be the member port. S8000 series: port 5
Member Role
Setting Description Factory Default
1st Member port Select any port of the S8000 series to be the 1st member port
S8000 series: port 4
2nd Member port
Select any port of the S8000 series to be the 2nd member port
S8000 series: port 5
Tail Role
Setting Description Factory Default
Tail Port Select any port of the S8000 series to be the tail port. S8000 series: port 4
Member Port Select any port of the S8000 series to be the member port. S8000 series: port 5
STP/RSTP
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 NPort S8000’s STP feature is disabled by default. To be completely
effective, you must enable RSTP/STP on every NPort S8000 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 NPort S8000. This feature
is particularly helpful when the NPort S8000’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?
STP (802.1D) is a bridge-based system that is used to implement parallel paths for network traffic. STP uses a
loop-detection process to:
• Locate and then disable less efficient paths (i.e., paths that have a lower bandwidth).
• Enable one of the less efficient paths if the most efficient path fails.