2950 with 2 vlan one shows down / down

Unanswered Question
Apr 14th, 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.

I have this problem too.
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Leo Laohoo Wed, 04/14/2010 - 22:04

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

Neeraj Arora Wed, 04/14/2010 - 22:11

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 Thu, 04/15/2010 - 00:34

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 Thu, 04/15/2010 - 07:04

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 Thu, 04/15/2010 - 11:32

   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 Thu, 04/22/2010 - 21:22

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 Wed, 04/21/2010 - 12:49

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.

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