[Try cadidate CCIE] Một câu hỏi nhỏ về STP

[tranmyphuc]

Imagine a simple topology made of 3 switches:
All switches are running STP for VLAN123 with SW3 being the root. Your task is to configure the network in such a way so that SW1 port fa0/13 is the root port and SW1 port fa0/16 is the alternate port for VLAN 123. Sound easy? Here are the requirements:
1) Do not change any STP link cost
2) SW3 must remain the root for VLAN 123
3) The port types must be access
4) Do not use the switchport backup interface command
5) Do not try to use SPAN or RSPAN
6) Do not disable STP

[Mr.LeVy]

Có phải là dùng Dot1q tunnel for SPT trên SW2 không, tuy nhiên vẫn chưa test thử nhưng về mặc theory thì ok ? Không tìm thấy cách nào khác ????

[mrsonkip]

ko ai có bài trả lời à. anh admin giải đáp đi :D

[binhhd]

Imagine a simple topology made of 3 switches:
All switches are running STP for VLAN123 with SW3 being the root. Your task is to configure the network in such a way so that SW1 port fa0/13 is the root port and SW1 port fa0/16 is the alternate port for VLAN 123. Sound easy? Here are the requirements:
1) Do not change any STP link cost
2) SW3 must remain the root for VLAN 123
3) The port types must be access
4) Do not use the switchport backup interface command
5) Do not try to use SPAN or RSPAN
6) Do not disable STP

i think this is the answer:
change bandwidth value on F0/16(SW1) to 10000 (10Mbps)

[tranmyphuc]

Có phải là dùng Dot1q tunnel for SPT trên SW2 không, tuy nhiên vẫn chưa test thử nhưng về mặc theory thì ok ? Không tìm thấy cách nào khác ????

Hi,
Correct Solution :
1) Configure SW2 to tunnel STP BPDUs between SW1 and SW3. This will make SW1 thinking that that SW3 is directly connected with cost 19. STP is still active on SW2, but SW2 considers itself the root.

SW2:

interface FastEthernet 0/13
l2protocol-tunnel stp
!
interface FastEthernet 0/16
l2protocol-tunnel stp

2) Configure SW3 port Fa0/16 with lower STP priority than SW3 Fa 0/13. This will make SW1 select its connection to SW2 as the root port and the other uplink is alternate: both uplinks have equal costs, the upstream port priority is the tiebreaker.

SW3:

interface FastEthernet 0/16
spanning-tree port-priority 64

==========================================

Theories for it :
Attach files

Thanks for reading my topic

[mrsonkip]

bai viet rat hay. cam on admin