Rstp; Pvst; Mstp - HP 6125XLG Configuration Manual

Hello time
•
The device sends hello packets at the hello time interval to the neighboring devices to make sure
the paths are fault-free.
Max age
•
The device uses the max age to determine whether a stored configuration BPDU has expired and
discards it if the max age is exceeded.

RSTP

RSTP achieves rapid network convergence by allowing a newly elected root port or designated port to
enter the forwarding state much faster than STP.
A newly elected RSTP root port rapidly enters the forwarding state when the following conditions exist:
• The old root port on the device has stopped forwarding data.
The upstream designated port has started forwarding data.
•
A newly elected RSTP designated port rapidly enters the forwarding state if it is an edge port or it
connects to a point-to-point link.
A port that directly connects to a user terminal can be configured as an edge port. Edge ports
•
directly enter the forwarding state.
When a designated port connects to a point-to-point link, it enters the forwarding state immediately
•
after the device receives a handshake response from the directly connected device.

PVST

In an STP- or RSTP-enabled LAN, all bridges share one spanning tree. Traffic from all VLANs is forwarded
along the spanning tree, and ports cannot be blocked on a per-VLAN basis to prune loops.
PVST allows every VLAN to have its own spanning tree, which increases utilization of links and
bandwidth. Because each VLAN runs STP or RSTP independently, a spanning tree only serves its VLAN.
A PVST-enabled HP device can communicate with a third-party device that is running Rapid PVST or PVST.
The PVST-enabled HP device supports fast network convergence like RSTP when connected to
PVST-enabled HP devices or third-party devices enabled with Rapid PVST.
A port's link type determines the type of BPDUs the port sends:
An access port sends STP BPDUs.
•
A trunk or hybrid port sends STP BPDUs in VLAN 1 and sends PVST BPDUs in other VLANs.
•

MSTP

MSTP overcomes the following STP, RSTP, and PVST limitations:
STP limitations—STP does not support rapid state transition of ports. A newly elected port must wait
•
twice the forward delay time before it transits to the forwarding state.
RSTP limitations—Although RSTP enables faster network convergence than STP, RSTP fails to
•
provide load balancing among VLANs. As with STP, all RSTP bridges in a LAN share one spanning
tree and forward packets from all VLANs along this spanning tree.
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