2950 with 2 vlan one shows down / down

Bhavesh30 · ‎04-14-2010

i configured 2 vlans on 2950 switch Vlan1(default) and Vlan20

i did no shutdown for vlan20 but it shows as down.

f0/3 is assigned to use vlan20 and i have a pc connected to the switch port 0/3. the LED on the port shows amber. i have default config on the switch only thing added is vlan20

Vlan20 is down, line protocol is down
Internet address is 10.0.1.1/24
Broadcast address is 255.255.255.255
Address determined by setup command
MTU is 1500 bytes
Helper address is not set
Directed broadcast forwarding is disabled
Outgoing access list is not set
Inbound access list is not set
Proxy ARP is enabled
Local Proxy ARP is disabled
Security level is default
Split horizon is enabled
ICMP redirects are always sent
ICMP unreachables are always sent
ICMP mask replies are never sent
IP fast switching is disabled
IP fast switching on the same interface is disabled
IP Null turbo vector
IP multicast fast switching is disabled
IP multicast distributed fast switching is disabled
IP route-cache flags are None
Router Discovery is disabled
IP output packet accounting is disabled
IP access violation accounting is disabled
TCP/IP header compression is disabled
RTP/IP header compression is disabled
Probe proxy name replies are disabled
Policy routing is disabled
Network address translation is disabled
WCCP Redirect outbound is disabled
WCCP Redirect inbound is disabled
WCCP Redirect exclude is disabled
BGP Policy Mapping is disabled
Switch#

the out put of Vlan's

interface Vlan1
ip address 192.168.0.1 255.255.255.0
no ip route-cache
!
interface Vlan20
ip address 10.0.1.1 255.255.255.0
no ip route-cache
!

i am very new to this concept and looking for any help i can get to have this working.

Leo Laohoo · ‎04-14-2010

The 2940/2950 series will only allow one active VLAN at any time.

Neeraj Arora · ‎04-14-2010

Bhavesh,

2950 is a Layer 2 switch, it does not support Inter-vlan routing and can only have one vlan interface active for Management purpose.

so what you are seeing is a normal behaviour of the switch. I am sure VLan 20 would be there are working on L2 i.e your switch will have separate broadcast domain for vlan 1 and vlan 20 but communication between these two cannot happen.

In case you want to keep two separate networks and want inter-vlan communication between them as well, then you would either need a router or you could use a L3 switch like 3560 or 3750 which supoorts Routing.

Refer to the following config guide for 2950 switch:

http://www.ciscosystems.com/en/US/docs/switches/lan/catalyst2950/software/release/12.1_9_ea1/configuration/guide/swvlan.html#wp1290566

Hope it helps

Neeraj

Ganesh Hariharan · ‎04-15-2010

i configured 2 vlans on 2950 switch Vlan1(default) and Vlan20

i did no shutdown for vlan20 but it shows as down.

f0/3 is assigned to use vlan20 and i have a pc connected to the switch port 0/3. the LED on the port shows amber. i have default config on the switch only thing added is vlan20

Vlan20 is down, line protocol is down

Internet address is 10.0.1.1/24

Broadcast address is 255.255.255.255

Address determined by setup command

MTU is 1500 bytes

Helper address is not set

Directed broadcast forwarding is disabled

Outgoing access list is not set

Inbound access list is not set

Proxy ARP is enabled

Local Proxy ARP is disabled

Security level is default

Split horizon is enabled

ICMP redirects are always sent

ICMP unreachables are always sent

ICMP mask replies are never sent

IP fast switching is disabled

IP fast switching on the same interface is disabled

IP Null turbo vector

IP multicast fast switching is disabled

IP multicast distributed fast switching is disabled

IP route-cache flags are None

Router Discovery is disabled

IP output packet accounting is disabled

Hi,

As suggested 2950 is L2 switch and can have only one SVI for management purpose and for troubleshooting purpose in future If the Layer 2 VLAN is not created on the switch, SVI interfaces show as UP/DOWN in the show ip interface brief command output when the configuration is applied to the switch. Ensure that all previous VLANs that were created in VLAN database mode or global configuration mode still exist after the configuration is copied to the switch.

Hope to Help !!

Ganesh.H

Bhavesh30 · ‎04-15-2010

Thnak you guys for the help and understaning the 2 vlan and its not supported in L2 switches.

so then why does it give option to create multiple VLAN's? i am sure there must be a reason for it.

glen.grant · ‎04-15-2010

I would make sure you understand the difference between a layer 2 vlan and a layer 3 SVI . You were creating a layer 3 SVI , this is to manage the switch remotely and that is all , it has no other function so you only need a single address on the switch . Because you may want to manage the switch on a vlan other than vlan 1 it will let you create another layer 3 SVI but you can only have a single layer 3 SVI active so you would need to shutdown the vlan 1 SVI. As far as layer 2 vlans it will support as many as the switch is capable of . If you need to route those vlans then you would have to have a trunk link going to either a router or a layer2/3 switch to do your routing .

dscarfe · ‎04-22-2010

You might need to have two layer 3 vlans defined on the switch at the same time if you are, for example, moving your management vlan off of vlan 1 (a good security practice). You would need to set up your new management vlan and then activate it--causing the vlan 1 ip interface to go down. This would allow you to migrate without having console access to the device.

Later,

Dave

fjcardenas-1 · ‎04-21-2010

As everyone mentioned. You can only have one VLAN for management purposes. But you still can create multiple VLANs in your L2 Switches to separate into multuple broadcast domains. May be you want to have VLAN 1 for some specific purpose (recomended only for management of the Switch) and VLAN 20 to connect all your hosts. In this scenario your hosts can never access the IP of your switch because it would be in a differnet VLAN (this would be the behavior if there is no a L3 switch or router). You would need to study also a little about the relation between VLAN and Subnets. Hope this helps a little. Feel free to rate my comment.