Chapter 7
| Spanning Tree Algorithm
Configuring Loopback Detection
– 167 –
An MST Region consists of a group of interconnected bridges that have the same
MST Configuration Identifiers (including the Region Name, Revision Level and
Configuration Digest – see
“Configuring Multiple Spanning Trees” on page 183
). An
MST Region may contain multiple MSTP Instances. An Internal Spanning Tree (IST)
is used to connect all the MSTP switches within an MST region. A Common
Spanning Tree (CST) interconnects all adjacent MST Regions, and acts as a virtual
bridge node for communications with STP or RSTP nodes in the global network.
Figure 94: Spanning Tree – Common Internal, Common, Internal
MSTP connects all bridges and LAN segments with a single Common and Internal
Spanning Tree (CIST). The CIST is formed as a result of the running spanning tree
algorithm between switches that support the STP, RSTP, MSTP protocols.
Once you specify the VLANs to include in a Multiple Spanning Tree Instance (MSTI),
the protocol will automatically build an MSTI tree to maintain connectivity among
each of the VLANs. MSTP maintains contact with the global network because each
instance is treated as an RSTP node in the Common Spanning Tree (CST).
Configuring Loopback Detection
Use the Spanning Tree > Loopback Detection page to configure loopback
detection on an interface. When loopback detection is enabled and a port or trunk
receives it’s own BPDU, the detection agent drops the loopback BPDU, sends an
SNMP trap, and places the interface in discarding mode. This loopback state can be
released manually or automatically. If the interface is configured for automatic
loopback release, then the port will only be returned to the forwarding state if one
of the following conditions is satisfied:
◆
The interface receives any other BPDU except for it’s own, or;
◆
The interfaces’s link status changes to link down and then link up again, or;
◆
The interface ceases to receive it’s own BPDUs in a forward delay interval.
Note:
If loopback detection is not enabled and an interface receives it's own BPDU,
then the interface will drop the loopback BPDU according to IEEE Standard 802.1w-
2001 9.3.4 (Note 1).
Region 1
Region 4
Region 2
Region 3
CIST
IST
Region 1
Region 4
Region 2
Region 3
CST
Содержание GEL-1061
Страница 14: ...Contents 14...
Страница 28: ...Section I Getting Started 28...
Страница 38: ...Chapter 1 Introduction System Defaults 38...
Страница 40: ...Section II Web Configuration 40...
Страница 60: ...Chapter 2 Using the Web Interface Navigating the Web Browser Interface 60...
Страница 164: ...Chapter 6 Address Table Settings Issuing MAC Address Traps 164...
Страница 192: ...Chapter 8 Congestion Control Storm Control 192...
Страница 204: ...Chapter 9 Class of Service Layer 3 4 Priority Settings 204...
Страница 216: ...Chapter 10 Quality of Service Attaching a Policy Map to a Port 216...
Страница 430: ...Chapter 14 Multicast Filtering MLD Snooping Snooping and Query for IPv4 430...
Страница 436: ...Chapter 15 IP Tools Address Resolution Protocol 436...
Страница 450: ...Chapter 16 IP Services Dynamic Host Configuration Protocol 450 Figure 301 Enabling Dynamic Provisioning via DHCP...
Страница 474: ...Section III Appendices 474...
Страница 492: ...Glossary 492...
Страница 500: ...E052016 ST R02 150200001416A...