Netgear XCM8806 - 8800 SERIES 6-SLOT CHASSIS SWITCH ユーザーズマニュアル
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Chapter 18. STP
NETGEAR 8800 User Manual
Overview
STP is a bridge-based mechanism for providing fault tolerance on networks. STP allows you
to implement parallel paths for network traffic and to ensure that redundant paths are:
to implement parallel paths for network traffic and to ensure that redundant paths are:
•
Disabled when the main paths are operational.
•
Enabled if the main path fails.
Compatibility Between IEEE 802.1D-1998 and IEEE
802.1D-2004 STP Bridges
The IEEE 802.1D-2004 compliant bridges interoperate with the IEEE 802.1D-1998 compliant
bridges. To ensure seamless operation of your STP network, read this section before you
configure STP.
bridges. To ensure seamless operation of your STP network, read this section before you
configure STP.
Differences in behavior between the two standards include the:
•
Default port path cost
•
Bridge priority
•
Port priority
•
Edge port behavior
This section describes the bridge behavior differences in more detail.
Default Port Path Cost
The 802.1D-2004 standard modified the default port path cost value to allow for higher link
speeds. A higher link speed can create a situation whereby an 802.1D-1998 compliant bridge
could become the more favorable transit path.
speeds. A higher link speed can create a situation whereby an 802.1D-1998 compliant bridge
could become the more favorable transit path.
, bridge A is the root bridge running the new 802.1D-2004
standard, bridges B and C are running the old 802.1D-1998 standard, and bridges D, E, and
F are running the new 802.1D-2004 standard. In addition, all ports are 100 Mbps links. The
ports on bridges B and C have a default path cost of 19, and the ports on bridge A, D, E, and
F have a default path cost of 200,000.
F are running the new 802.1D-2004 standard. In addition, all ports are 100 Mbps links. The
ports on bridges B and C have a default path cost of 19, and the ports on bridge A, D, E, and
F have a default path cost of 200,000.