Thursday, October 13, 2011

Comware - PVST+


1.      STP and RSTP cannot load balance, therefore PVST created by Cisco. 

            Protoco            Developer               VLAN ID
            MSTP               IEEE (802.1Q)         802.1Q
            PVST                Cisco                        ISL
            PVST+              Cisco                        802.1Q

2.       Comware v5 implements MSTP
3.       New software releases add PVST+ to Comware v5 switches


Configuration Steps

1.       Configure 3 VLANs
  1. Create a spanning tree per VLAN
  2. Configure
       Switch A as root of VLAN 1
       Switch B as root of VLAN 2
       Switch C as root of VLAN 3 

  1. Note: in this example it is assumed that Switch A has the smallest default Bridge-ID


Test Layout


1.        Configure all VLANs

  1. Enable STP in system-view
stp enable 

3.       Change the STP mode to PVST

stp mode pvst

4.       Connect the switches 

Notes
The STP default mode is MSTP
At this point a Spanning Tree has been created for each VLAN. All spanning trees have the same root

  1. Change the bridge priority for individual VLANs or for lists of VLANs
stp vlan vlan-list priority priority value

Figure 1: Test Network Layout

1.    On all three switches

a.    Create VLANs 2-6
b.    Configure ports 1 and 2 as “link-type trunk” permitting all VLANs
c.    Enable STP
d.    Change STP mode to PVST+


2.    Connect Cables following figure 1.

Commands

system-view
 vlan 2 to 6

 interface gigabit 0/1
  port link-type trunk
  port trunk permit vlan all
  quit
 interface gigabit 0/2
  port link-type trunk
  port trunk permit vlan all
  quit
 stp enable
 stp mode pvst
 quit


3.    Check the stp configuration. Notice that the root bridge for all STP instances is the same.

Commands
display stp root
display stp brief


4.    Change the root of different instances:

a.    Switch 1: VLAN 1 and 2
b.    Switch 2: VLAN 3 and 4
c.    Switch 3: VLAN 5 and 6

Example

Switch A:
system-view
 stp vlan 1 priority 4096
 quit

Switch B:
system-view
 stp vlan 2 priority 4096
 quit

Switch C:
system-view
 stp vlan 3 priority 4096
 quit



Result 

1.    Verify that the root bridges changed

Commands
display stp root
display stp brief


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Please add comments so I can update material to accomodate platform modification to various commands. Also if you have some real world caveats, do please share.

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Central Florida, United States