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Adding a group of ports to a range of VLANs sends multiple messages to the rapid spanning tree protocol (RSTP) task, avoid
using the
range
command. When using the
range
command, Dell Networking recommends limiting the range to five ports and
40 VLANs.
RSTP and VLT
Virtual link trunking (VLT) provides loop-free redundant topologies and does not require RSTP.
RSTP can cause temporary port state blocking and may cause topology changes after link or node failures. Spanning tree topology
changes are distributed to the entire Layer 2 network, which can cause a network-wide flush of learned media access control (MAC)
and address resolution protocol (ARP) addresses, requiring these addresses to be re-learned. However, enabling RSTP can detect
potential loops caused by non-system issues such as cabling errors or incorrect configurations. RSTP is useful for potential loop
detection but to minimize possible topology changes after link or node failure, configure it using the following specifications.
The following recommendations help you avoid these issues and the associated traffic loss caused by using RSTP when you enable
VLT on both VLT peers:
•
Configure any ports at the edge of the spanning tree’s operating domain as edge ports, which are directly connected to end
stations or server racks. Ports connected directly to Layer 3-only routers not running STP should have RSTP disabled or be
configured as edge ports.
•
Ensure that the primary VLT node is the root bridge and the secondary VLT peer node has the second-best bridge ID in the
network. If the primary VLT peer node fails, the secondary VLT peer node becomes the root bridge, avoiding problems with
spanning tree port state changes that occur when a VLT node fails or recovers.
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Even with this configuration, if the node has non-VLT ports using RSTP that are not configured as edge ports and are connected
to other layer 2 switches, spanning tree topology changes can still be detected after VLT node recovery. To avoid this scenario,
ensure that you configure any non-VLT ports as edge ports or have RSTP disabled.
Configuring Interfaces for Layer 2 Mode
To configure and enable interfaces in Layer 2 mode, use the following commands.
All interfaces on all bridges that participate in Rapid Spanning Tree must be in Layer 2 and enabled.
1.
If the interface has been assigned an IP address, remove it.
INTERFACE mode
no ip address
2.
Place the interface in Layer 2 mode.
INTERFACE mode
switchport
3.
Enable the interface.
INTERFACE mode
no shutdown
Example of Verifying an Interface is in Layer 2 Mode and Enabled
To verify that an interface is in Layer 2 mode and enabled, use the
show config
command from INTERFACE mode. The bold lines
indicate that the interface is in Layer 2 mode.
Enabling Rapid Spanning Tree Protocol Globally
Enable RSTP globally on all participating bridges; it is not enabled by default.
When you enable RSTP, all physical and port-channel interfaces that are enabled and in Layer 2 mode are automatically part of the
RST topology.
•
Only one path from any bridge to any other bridge is enabled.
Rapid Spanning Tree Protocol (RSTP)
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Содержание S4048-ON
Страница 1: ...Dell Configuration Guide for the S4048 ON System 9 9 0 0 ...
Страница 146: ...Figure 14 BFD Three Way Handshake State Changes 146 Bidirectional Forwarding Detection BFD ...
Страница 477: ...Figure 68 Inspecting Configuration of LAG 10 on ALPHA Link Aggregation Control Protocol LACP 477 ...
Страница 480: ...Figure 70 Inspecting a LAG Port on BRAVO Using the show interface Command 480 Link Aggregation Control Protocol LACP ...
Страница 481: ...Figure 71 Inspecting LAG 10 Using the show interfaces port channel Command Link Aggregation Control Protocol LACP 481 ...
Страница 522: ...Figure 87 Configuring Interfaces for MSDP 522 Multicast Source Discovery Protocol MSDP ...
Страница 523: ...Figure 88 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 523 ...
Страница 524: ...Figure 89 Configuring PIM in Multiple Routing Domains 524 Multicast Source Discovery Protocol MSDP ...
Страница 528: ...Figure 91 MSDP Default Peer Scenario 1 528 Multicast Source Discovery Protocol MSDP ...
Страница 529: ...Figure 92 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 529 ...
Страница 530: ...Figure 93 MSDP Default Peer Scenario 3 530 Multicast Source Discovery Protocol MSDP ...
Страница 633: ...Policy based Routing PBR 633 ...
Страница 777: ...Figure 119 Single and Double Tag TPID Match Service Provider Bridging 777 ...
Страница 778: ...Figure 120 Single and Double Tag First byte TPID Match 778 Service Provider Bridging ...