This has exhausted every resource I've found and nothing explains why enabling any vLAN besides the management vLAN automatically shutdowns the management vLAN rendering their switch ports useless for IP traffic.
It's a portable CCNA lab and following the exercises in Cisco's Exploration 3 and 4... creating a new management vLAN or using the default mgmt vLAN1 still Administratively shutdowns the currently running vLAN after "no shut" a different vLAN.
Switches aren't constrained to just one running vLAN, but why is my config instantly shutting down the other singular operating vLAN the instant I "no shut" a different vLAN.
Appended an abridged running config and thoroughly exhausted the troubleshooting methods. More suggestions for additional troubleshooting are well meant...
I'm in need of some skilled peek of my flawed config instead of more suggestions cause I've exhaustively troublehshooted and switched cables to the infinite.
By now, I'm leaning towards some insidious Cisco limitation in a workgroup switch but the 2940 has seemingly executed every function w/o objection.
Thanks in advance
====RUNNING CONFIG (ABRIDGED FOR CLARITY)
spanning-tree mode pvst no spanning-tree optimize bpdu transmission spanning-tree extend system-id ! interface FastEthernet0/1 switchport access vlan 99 switchport mode dynamic auto mdix auto spanning-tree portfast ! interface FastEthernet0/2 switchport access vlan 99 switchport mode dynamic auto mdix auto ! interface FastEthernet0/3 switchport access vlan 30 mdix auto ! interface FastEthernet0/4 switchport access vlan 20 switchport trunk native vlan 20 switchport mode dynamic auto mdix auto
interface Vlan1 no ip address no ip route-cache shutdown ! interface Vlan12 no ip address no ip route-cache ! interface Vlan20 ip address 172.16.20.20 255.255.255.0 no ip route-cache shutdown ! interface Vlan99 ip address 172.16.1.3 255.255.255.0 no ip route-cache
Enabling VLAN interface:
square(config-if-range)#inte vlan 99 square(config-if)#no shut square(config-if)# 00:58:52: %LINK-3-UPDOWN: Interface Vlan99, changed state to up 00:58:52: %LINK-5-CHANGED: Interface Vlan20, changed state to administratively down 00:58:53: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan99, changed state to up
do sh vlan brief
VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 1 default active Fa0/5, Fa0/6, Fa0/7, Fa0/8 Gi0/1 10 FacultyStaff active 20 Students active Fa0/4 30 Guest active Fa0/3 99 ManagementNative active Fa0/1, Fa0/2 1002 fddi-default act/unsup 1003 token-ring-default act/unsup 1004 fddinet-default act/unsup 1005 trnet-default act/unsup