07-23-2011 10:46 AM - edited 03-04-2019 01:04 PM
I have build topology like this:
host------c2950(f0/3)------(f0/4)c3550(f0/41)----modem-----Internet
I wanted to monitor c3560 port where modem is connected from host. So for that I configured rspan. configurate show below. But problem is that after configuration f0/4 of c3550 remains up and f0/3 of c2950 goes down. WHen I look at status of f0/4 it show "FastEthernet0/4 is up, line protocol is down (monitoring)". I tried to search websites It seems configuration is fine. Kindly help.
on c3550:
interface FastEthernet0/4
switchport trunk encapsulation dot1q
switchport mode trunk
switchport nonegotiate
interface FastEthernet0/41
switchport mode dynamic desirable
spanning-tree portfast
monitor session 2 destination interface Fa0/8
monitor session 2 source remote vlan 20
interface FastEthernet0/9
switchport mode access
spanning-tree portfast
spanning-tree guard loop
end
interface FastEthernet0/3
switchport mode trunk
switchport nonegotiate
spanning-tree guard loop
ip dhcp snooping trust
end
monitor session 1 source interface Fa0/41
monitor session 1 destination remote vlan 20 reflector-port Fa0/4
on c2950:
monitor session 2 destination interface Fa0/9
monitor session 2 source remote vlan 20
interface FastEthernet0/9
switchport mode access
spanning-tree portfast
spanning-tree guard loop
end
interface FastEthernet0/3
switchport mode trunk
switchport nonegotiate
spanning-tree guard loop
ip dhcp snooping trust
end
07-23-2011 11:23 AM
Rahil,
Here is the problem, the port fa4 is a trunk port & a trunk port cannot be configured as reflector port. so, what you are seeing is expected.
When you configure a switch port as a reflector port, it is no longer a normal switch port; only looped-back traffic passes through the reflector port.
The reflector ports should not have any physical connection and should remain vacant.
If you have a free port available on 3550, configure it as a reflector & things should work fine.
Also, make sure that you have RSPAN vlan configured on both the switches.
Ref Guide:
Regards,
Amit Aneja
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