•
Dell Networking OS supports only one Rapid Spanning Tree (RST) instance.
•
All interfaces in virtual local area networks (VLANs) and all enabled interfaces in Layer 2 mode are automatically added to the RST
topology.
•
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.
•
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.
Rapid Spanning Tree Protocol (RSTP)
783
Содержание S4048T-ON
Страница 1: ...Dell Configuration Guide for the S4048 ON System 9 11 2 1 ...
Страница 148: ...Figure 10 BFD Three Way Handshake State Changes 148 Bidirectional Forwarding Detection BFD ...
Страница 251: ...Dell Control Plane Policing CoPP 251 ...
Страница 363: ... RPM Synchronization GARP VLAN Registration Protocol GVRP 363 ...
Страница 511: ...Figure 64 Inspecting the LAG Configuration Link Aggregation Control Protocol LACP 511 ...
Страница 512: ...Figure 65 Inspecting Configuration of LAG 10 on ALPHA 512 Link Aggregation Control Protocol LACP ...
Страница 515: ...Figure 67 Inspecting a LAG Port on BRAVO Using the show interface Command Link Aggregation Control Protocol LACP 515 ...
Страница 516: ...Figure 68 Inspecting LAG 10 Using the show interfaces port channel Command 516 Link Aggregation Control Protocol LACP ...
Страница 558: ...Figure 84 Configuring Interfaces for MSDP 558 Multicast Source Discovery Protocol MSDP ...
Страница 559: ...Figure 85 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 559 ...
Страница 560: ...Figure 86 Configuring PIM in Multiple Routing Domains 560 Multicast Source Discovery Protocol MSDP ...
Страница 564: ...Figure 88 MSDP Default Peer Scenario 2 564 Multicast Source Discovery Protocol MSDP ...
Страница 565: ...Figure 89 MSDP Default Peer Scenario 3 Multicast Source Discovery Protocol MSDP 565 ...
Страница 729: ...protocol spanning tree pvst no disable vlan 300 bridge priority 4096 Per VLAN Spanning Tree Plus PVST 729 ...
Страница 841: ...Figure 115 Single and Double Tag TPID Match Service Provider Bridging 841 ...
Страница 842: ...Figure 116 Single and Double Tag First byte TPID Match 842 Service Provider Bridging ...