just1moretime
Technical User
I am trying to learn spanning tree. Using Cisco Packet
Tracer with 3 switches and 2 hubs for a basic example.
All switch settings default.
Sw0 G1/0 + Sw1 G1/0 + Sw2 G1/0 all to hub 0
Sw0 G1/1 + Sw1 G1/1 + Sw2 G1/1 all to hub 1
According to my calculations, the wrong switch comes up the root bridge.
Here is my data:
S0 G1/0-MAC-0001.C99B.7C01 TO HUB 0 PORT 0
S0 G1/1-MAC-0001.C99B.7C02 TO HUB 1 PORT 0
S1-G1/0-MAC-0000.0C07.BB01 TO HUB 0 PORT 1
S1-G1/1-MAC-0000.0C07.BB02 TO HUB 1 PORT 1
S2-G1/1-MAC 0060.3E04.3701 TO HUB 0 PORT 2
S2 G1/2-MAC-0060.3E04.3702 TO HUB 1 PORT 2
IN PACKET TRACER SW 0 COMES UP ROOT BRIDGE.
USING SHOW SPANNING TREE cmd, ROOT MAC IS 0010.1130.98DC. HOW DID THIS NUMBER COME ABOUT?
MY thoughts/miscalculations:
I DONT UNDERSTAND. ACCORDING TO MY CALCULATIONS, SW 1 SHOULD
BE THE ROOT BECAUSE LOWEST MAC.
AM I FIGURING BRIDGE ID CORRECTLY?
S1 G1/0 0000.0C07.BBO1 = 201,833,217 201,833,217+32768= 210,865,985 BRIDGE ID SW 1
SO G1/0 0001.C99B.7C01 = 7,677,377,537
7,677,377,537+32768=7,677,410,305 BRIDGE ID SW 0 x
S2 G1/0 0060.3E04.3701 = 413,357,324,033
413,357,324,033 + 32768 = 413,357,356,801 BRIDGE ID SW 2
THANKS FOR YOUR HELP.
Tracer with 3 switches and 2 hubs for a basic example.
All switch settings default.
Sw0 G1/0 + Sw1 G1/0 + Sw2 G1/0 all to hub 0
Sw0 G1/1 + Sw1 G1/1 + Sw2 G1/1 all to hub 1
According to my calculations, the wrong switch comes up the root bridge.
Here is my data:
S0 G1/0-MAC-0001.C99B.7C01 TO HUB 0 PORT 0
S0 G1/1-MAC-0001.C99B.7C02 TO HUB 1 PORT 0
S1-G1/0-MAC-0000.0C07.BB01 TO HUB 0 PORT 1
S1-G1/1-MAC-0000.0C07.BB02 TO HUB 1 PORT 1
S2-G1/1-MAC 0060.3E04.3701 TO HUB 0 PORT 2
S2 G1/2-MAC-0060.3E04.3702 TO HUB 1 PORT 2
IN PACKET TRACER SW 0 COMES UP ROOT BRIDGE.
USING SHOW SPANNING TREE cmd, ROOT MAC IS 0010.1130.98DC. HOW DID THIS NUMBER COME ABOUT?
MY thoughts/miscalculations:
I DONT UNDERSTAND. ACCORDING TO MY CALCULATIONS, SW 1 SHOULD
BE THE ROOT BECAUSE LOWEST MAC.
AM I FIGURING BRIDGE ID CORRECTLY?
S1 G1/0 0000.0C07.BBO1 = 201,833,217 201,833,217+32768= 210,865,985 BRIDGE ID SW 1
SO G1/0 0001.C99B.7C01 = 7,677,377,537
7,677,377,537+32768=7,677,410,305 BRIDGE ID SW 0 x
S2 G1/0 0060.3E04.3701 = 413,357,324,033
413,357,324,033 + 32768 = 413,357,356,801 BRIDGE ID SW 2
THANKS FOR YOUR HELP.