HP 5500 Ei 5500 Si Switch Series Configuration Guide

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•  Same VLAN-to-instance mapping configuration 
•   Same MSTP revision level 
•   Physically linked together 
Multiple MST regions can exist in a switched network. You can assign multiple devices to the same MST 
region. In  Figure 20,
 the switched network comprises four MST regions, MST region 1 through MST 
region 4, and all devices in each MST region have the same MST region configuration. 
MSTI 
MSTP can generate multiple independent spanning tr ees in an MST region, and each spanning tree is...

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Port roles 
A port can play different roles in different MSTIs. As shown in Figure 22, an  MST region comprises Device 
A, Device B, Device C, and Device D. Port A1 and port A2 of Device A connect to the common root 
bridge. Port B2 and Port B3 of Device B form a loop. Port C3 and Port C4 of Device C connect to other 
MST regions. Port D3 of Device D directly connects to a host. 
Figure 22  Port roles 
 
 
MSTP calculation involves the following port roles: 
•  Root  port —Forwards data for a...

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•  Forwarding —The port receives and sends BPDUs, obtains MAC addresses, and forwards user 
traffic. 
•   Learning —The port receives and sends BPDUs, obtains MAC addresses, but does not forward user 
traffic. Learning is an  intermediate port state. 
•   Discarding —The port receives and sends BPDUs, but does not obtain MAC addresses or forward 
user traffic. 
When in different MSTIs, a port can be in different st ates. A port state is not exclusively associated with 
a port role.  Table 13 lists...

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In addition to basic MSTP functions, the following functions are provided for ease of management: 
•  Root bridge hold 
•   Root bridge backup 
•   Root guard 
•   BPDU guard 
•   Loop guard 
•   TC-BPDU guard 
•   BPDU drop. 
Protocols and standards 
The spanning tree protocols are docu mented in the following standards: 
•   IEEE 802.1d,  Media Access Control (MAC) Bridges  
•   IEEE 802.1w,  Part 3: Media Access Control (MAC) Bridges—Amendment 2: Rapid Reconfiguration 
•   IEEE 802.1s,  Virtual...

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Task Remarks 
Configuring the 
root bridge Setting the spanning tree mode 
Required 
Configure the device to 
operate in STP-compatible 
mode. 
Configuring the root bridge or a secondary root bridge 
Optional 
Configuring the device priority Optional 
Configuring the network diameter of a switched network Optional 
Configuring spanning tree timers Optional 
Configuring the timeout factor Optional 
Configuring the maximum port rate Optional 
Configuring the mode a port uses to recognize/send MSTP...

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Task Remarks 
Configuring spanning tree timers  Optional 
Configuring the timeout factor Optional 
Configuring the maximum port rate Optional 
Configuring edge ports Optional 
Configuring the port link type Optional 
Configuring the mode a port uses to recognize/send MSTP 
packets  Optional 
Enabling outputting port state transition information 
Optional 
Enabling the spanning tree feature Required 
Configuring 
the leaf 
nodes Setting the spanning tree mode 
Required 
Configure the device to...

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Task Remarks 
Configuring spanning tree timers Optional 
Configuring the timeout factor Optional 
Configuring the maximum port rate Optional 
Configuring edge ports Optional 
Configuring the port link type Optional 
Enabling outputting port state transition 
information Optional 
Enabling the spanning tree feature 
Required 
Configuring 
the leaf 
nodes Setting the spanning tree mode 
Required 
Configure the device to operate in PVST 
mode. 
Configuring the device priority 
Optional 
Configuring the...

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Task Remarks 
Configuring the maximum port rate  Optional 
Configuring edge ports Optional 
Configuring the port link type Optional 
Configuring the mode a port uses to recognize/send MSTP packets Optional 
Enabling outputting port state transition information Optional 
Enabling the spanning tree feature Required 
Configuri
ng the leaf 
nodes Setting the spanning tree mode 
Optional 
By default, the device 
operates in MSTP mode.
 
Configuring an MST region 
Required 
Configuring the device priority...

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The MSTP mode is compatible with the RSTP mode, and the RSTP mode is compatible with the STP mode. 
The PVST modes compatibility with the other spanning tree mode varies by port type: 
•   On an access port, the PVST mode is compatible  with any other spanning tree mode in any VLAN.   
•   On a trunk or hybrid port, the PVST mode is compat ible with any other spanning tree mode in only 
VLAN 1.  
Whether you need to specify the MSTI or VLAN for the spanning tree configuration varies with the...

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Step Command Remarks 
2.  Enter MST region view.  
stp region-configuration  N/A 
3.  Configure the MST 
region name.   region-name
 name   Optional. 
The MST region name is the MAC address 
by default.
 
4.  Configure the 
VLAN-to-instance 
mapping table.  • instance  instance-id  vlan  
vlan-list  
• vlan-mapping modulo  
modulo   Optional. 
Use either command. 
All VLANs in an MST region are mapped 
to the CIST (or MSTI 0) by default.
 
5.  Configure the MSTP 
revision level of the MST 
region....