www.howtonetwork.org

CCNA & CCNP Certifcation Training

  • About
  • Contact
  • FAQ
  • Join
  • Home
  • CCNA
    • ICND1
    • ICND2
    • 101 CCNA LABS
  • CCNP
    • ROUTE
    • SWITCH
    • TSHOOT
    • 101 CCNP LABS
  • CompTIA
    • Security+
    • Network+
  • Design
    • CCDA
    • CCDP
You are here: Home / 101 CCNA LABS / Local Area Networks Solutions / Lab 8 Solution: Spanning-Tree Protocol Root Bridges using the IOS Macro

Lab 8 Solution: Spanning-Tree Protocol Root Bridges using the IOS Macro

Task 1:

For reference information on configuring hostnames, please refer to:

Lab 1 Configuration and Verification Task 1

Lab 3 Configuration and Verification Task 1

Task 2:

NOTE: By default, Cisco switches are VTP servers. However, to configure the extended range of VLANs, i.e. VLANs 1006 and above, you need to configure the switch as a VTP Transparent switch.

For reference information on Transparent mode and extended VLANs, please refer to:

Lab 2 Configuration and Verification Task 1

Lab 4 Configuration and Verification Task 4

Task 3:

NOTE: The spanning-tree vlan <number> root primary command is a macro that allows Catalyst switches to automatically configure a Spanning-Tree priority value that ensures that the switch this command is issued on will most likely be elected Root Bridge. The spanning-tree vlan <number> root secondary is a macro that allows Catalyst switches to automatically configure a Spanning-Tree priority value that ensures that the switch this command is issued on will most likely be elected backup Root Bridge.

Sw1#conf t

Enter configuration commands, one per line.  End with CNTL/Z.

Sw1(config)#spanning-tree vlan 2010 root primary

Sw1(config)#spanning-tree vlan 2030 root primary

Sw1(config)#spanning-tree vlan 2020 root secondary

Sw1(config)#spanning-tree vlan 2040 root secondary

Sw1(config)#end

Sw1#

Sw1#conf t

Enter configuration commands, one per line.  End with CNTL/Z.

Sw2(config)#spanning-tree vlan 2020 root primary

Sw2(config)#spanning-tree vlan 2040 root primary

Sw2(config)#spanning-tree vlan 2010 root secondary

Sw2(config)#spanning-tree vlan 2030 root secondary

Sw2(config)#end

Sw2#

Task 4:

NOTE: Use this command to verify the same for VLAN 2030, as well as for VLANs 2020 and 2040 on switch Sw2. In addition to this, you can also issue the show spanning-tree root command to view the Spanning-Tree Root Bridge for all VLANs in the domain. This is illustrated below:
Sw1#show spanning-tree root
Fwd
Root ID Root Cost Hello Time Max Age Vlan Dly Root Port
—————- ——————– —— —– — — —————-
VLAN2010 26586 000d.bd06.4100 0 2 20 15

Sw1#show spanning-tree vlan 2010

VLAN2010

Spanning tree enabled protocol ieee

Root ID    Priority    26586

Address     000d.bd06.4100

This bridge is the root

Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

Bridge ID  Priority    26586  (priority 24576 sys-id-ext 2010)

Address     000d.bd06.4100

Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

Aging Time 300

Interface Role Sts Cost Prio.Nbr Type
—————- —- — ——— ——– ——————————–
Fa0/2 Desg FWD 100 128.2 Shr

 

NOTE:  Notice the strange Priority value. This means that there is no switch in the switched LAN that has a priority that is numerically less than the manually set value of 28672. To test the macro, change the priority of VLAN 2010 on switch Sw2 to 20480 and then check the priority on Sw1 again. Try the reverse and change priorities on Sw1 and see Sw2 Spanning-Tree priority values change.

 

Prev

Next

About Us

This is a free bonus site for members of www.howtonetwork.com

Copyright

The content on this copyright Reality Press Ltd.
Copyright Reality Press Ltd.