HP 5500 Ei 5500 Si Switch Series Configuration Guide

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Step Command Remarks 
3.  Configure the mode that 
the port uses to 
recognize/send MSTP 
packets.   stp compliance 
{ auto  | dot1s  | legacy  } auto  by default.
 
 
Enabling outputting port state transition information 
In a large-scale spanning tree network, you can enable devices to output the port state transition 
information of all MSTIs or the specified MSTI in  order to monitor the port states in real time. 
To enable outputting port state transition information: 
 
Step Command Remarks...

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Step Command Remarks 
1.  Enter system view. 
system-view  N/A 
2.  Enable the spanning 
tree feature globally.  stp enable  By default, the spanning tree 
feature is disabled globally. 
 
3.  Enter interface view or 
port group view. 
• Enter Layer 2 Ethernet interface view or 
Layer 2 aggregate interface view: 
interface interface-type interface-number  
• Enter port group view:  
port-group manual  port-group-name Use either command.
 
4.  Enable the spanning 
tree feature for the 
port or group...

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Suppose Device A running STP, Device B with no spanning tree feature enabled, and Device C running 
RSTP or MSTP are connected in order. Device B will transparently transmit the STP BPDUs, and the port 
on Device C and connecting to Device B will transition to the STP mode. After you enable the spanning 
tree feature on Device B, to run RSTP or MSTP between Device B and Device C, you must perform an 
mCheck operation on the ports interconnecting Device B and Device C, in addition to configuring the...

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•  With digest snooping enabled, in-the-same-region verification does not require comparison of 
configuration digest, so the VLAN-to-instance mapp ings must be the same on associated ports.  
•   W i t h  g l o b a l  D i g e s t  S n o o p i n g  e n a b l e d ,  m o d i f i c a t i on of VLAN-to-instance mappings and removal of 
the current region configuration via the  undo stp region-configuration command are not allowed. 
You can modify only the region name and revision level. 
•   To make...

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Figure 23 Digest Snooping configuration 
 
 
Configuration procedure 
# Enable Digest Snooping on GigabitEthernet 1/0/1 of Device A and enable global Digest 
Snooping on Device A. 
 system-view 
[DeviceA] interface gigabitethernet 1/0/1 
[DeviceA-GigabitEthernet1/0/1] stp config-digest-snooping 
[DeviceA-GigabitEthernet1/0/1] quit 
[DeviceA] stp config-digest-snooping 
# Enable Digest Snooping on GigabitEthernet 1/ 0/1 of Device B and enable global Digest 
Snooping on Device B. 
 system-view...

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Figure 24 Rapid state transition of an MSTP designated port  
 
 
Figure 25 Rapid state transition of an RSTP designated port  
 
 
If the upstream device is a third-party device, the rapid state transition implementation might be limited. 
For example, when the upstream device uses a rapid tr ansition mechanism similar to that of RSTP, and the 
downstream device adopts MSTP and does not operate  in RSTP mode, the root port on the downstream 
device receives no agreement packet from the upstream...

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To configure No Agreement Check:  
Step Command Remarks 
1.  Enter system view. 
system-view  N/A 
2.  Enter interface view or port 
group view. 
• Enter Layer 2 Ethernet interface view or 
Layer 2 aggregate interface view: 
interface interface-type interface-number
 
• Enter port group view:  
port-group manual  port-group-name Use either command.
 
3.  Enable No Agreement 
Check.  stp no-agreement-check 
Disabled by default. 
 
No Agreement Check configuration example 
Network requirements 
As...

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Figure 27 TC snooping application scenario 
 
 
In the network, the IRF fabric transparently transmits the received BPDUs and does not participate in 
spanning tree calculations. When a  topology change occurs to the IRF fabric or user networks, the IRF 
fabric may need a long time to learn the correct MAC address table entries and ARP entries, resulting in 
long network disruption. To avoid the network disruption, you can enable TC snooping on the IRF fabric.   
With TC snooping enabled, a device...

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Configuring protection functions 
A spanning tree device supports the following protection functions: 
•  BPDU guard 
•   Root guard 
•   Loop guard 
•   TC-BPDU guard 
•   BPDU drop 
Configuration prerequisites 
The spanning tree feature has been correctly configured on the device. 
Enabling BPDU guard 
For access layer devices, the access ports can directly connect to the user terminals (such as PCs) or file 
servers. The access ports are configured as edge ports to allow rapid transition. When...

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traffic that should go over high-speed links is switched to low-speed links, resulting in network 
congestion. 
To prevent this situation, MSTP provides the root guar d function. If the root guard function is enabled on 
a port of a root bridge, this port plays the role of de signated por t on all MSTIs. After this por t receives a 
configuration BPDU with a higher priority from an MSTI, it immediately sets that  port to the listening state 
in the MSTI, without forwarding the packet. This is...