User`s manual

PT-G7509 User’s Manual Featured Functions
3-37
Head Role
Setting Description Factory Default
Head Port
Select any port of the PT to be the head
port.
port G8
Member Port
Select any port of the PT to be the member
port.
port G9
Member Role
Setting Description Factory Default
1
st
Member port
Select any port of the PT to be the 1
st
member port
Port G8
2
nd
Member port
Select any port of the PT to be the 2
nd
member port
Port G9
Tail Role
Setting Description Factory Default
Tail Port Select any port of the PT to be the tail port. Port G8
Member Port
Select any port of the PT to be the member
port.
Port G9
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 PT-G7509’s STP feature is disabled by
default. To be completely effective, you must enable RSTP/STP on every PT-G7509 connected to
your network.
Rapid Spanning Tree Protocol (RSTP) implements the Spanning Tree Algorithm and Protocol
defined by IEEE Std 802.1D-2004. RSTP provides the following benefits:
y The topology of a bridged network will be determined much more quickly compared to STP.
y RSTP is backward compatible with STP, making it relatively easy to deploy. For example:
¾ It defaults to sending 802.1D style BPDUs if packets with this format are received.
¾ STP (802.1D) and RSTP (802.1w) can operate on different ports of the same PT-G7509.
This feature is particularly helpful when PT-G7509 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
different, please refer to Differences between RSTP and STP later in this chapter.
NOTE
The STP protocol is part of the IEEE Std 802.1D, 2004 Edition bridge specification. The
explanation given below uses bridge instead of switch.