vlan interface down

[DonnaJ]

How do figure out why? I tryed no shut down, still down...

41-Switch-1#sh int vlan 3

Vlan3 is down, line protocol is down

Hardware is EtherSVI, address is 000a.f421.e800 (bia 000a.f421.e800)

Internet address is 10.7.41.210/24

MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

ARP type: ARPA, ARP Timeout 04:00:00

Last input never, output never, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

0 packets input, 0 bytes, 0 no buffer

Received 0 broadcasts (0 IP multicast)

0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 packets output, 0 bytes, 0 underruns

0 output errors, 1 interface resets

0 output buffer failures, 0 output buffers swapped out

[massimiliano.serafino]

Hi,

Do you have ports in VLAN 3? Try to put one port in VLAN 3..

I hope this helps.

Best regards.

Massimiliano.

[mohammedmahmoud]

Hi,

There needs to be atleast 1 up/up interface within the VLAN for the VLAN SVI interface to be in an up/up state - one port in the VLAN should be in the connected state or there should be a running trunk to another switch - if the SVI interface is created but the VLAN is not configured on the switch the SVI interface will be down/down (which is your case), if the VLAN is created on the switch but no port assigned to this VLAN is UP/UP the SVI becomes up/down.

BR,

Mohammed Mahmoud.

[Richard Burts]

DJ

The suggestions about needing to have at least 1 active port (or inclusion in an active trunk) is a good point. Another question is whether this switch is a layer 2 switch or layer 3 switch. Layer 3 switches can have multiple VLAN interfaces that are active. A layer 2 switch can have multiple VLANs but can have only 1 VLAN interface that is active. If this is a layer 2 switch and if there is another VLAN interface would be a reason why this VLAN interface is down.

HTH

Rick

[mohammedmahmoud]

Hi Rick,

I believe that layer 2 switches will have only one UP/UP SVI for management, while any other created SVI will be in the administratively down status (at least this was the case with my 2900XL), but since this SVI is down/down then i believe that as i've suggested the VLAN is not configured on the switch.

[edit] Another thing, from the output, "Hardware is EtherSVI", this is only the case with L3 switches, if it was L2 i believe it should be "Hardware is CPU Interface".

BR,

Mohammed Mahmoud.

[mahesh18]

Hi Mohammed

what is SVI interface in vlan.my understanding is that when we make the vlan

aqnd assign it physical interfaces then that

vlan is SVI?

if not please explain me what is SVI?and when

and why do we need it?

also how is it different form VLAN?

[Jon Marshall]

Mahesh

SVI = Switched Virtual Interface.

When you create a vlan ie.

3550(config)# vlan 10

3550(config-vlan)# name v10

this vlan is a L2 vlan. If you allocate ports into this vlan then any devices attached to this port can communicate with each other.

But if you had another vlan eg. vlan 11 and you wanted your devices in vlan 10 to be able to communicate with devices in vlan 11 you need to create SVI's for each vlan. These SVI are L3 interfaces for the vlans and they allow inter-vlan routing. An SVI is created by

3550(config)# int vlan 10

3550(config-if)# ip address 192.168.5.1 255.255.255.0

and then set the default-gateway on each device in vlan 10 to be 192.168.5.1.

Jon

[mahesh18]

Hi Jon,

thanks for reply

so these SVI can we create these on layer

2 switches by assigning them IP address or

they have to be in layer 3 device like Router

or Layer 3 switch?

[Jon Marshall]

Mahesh

On a layer 2 switch you can have one SVI only and this SVI is used for remotely accessing the switch to manage it. You would not use the IP address of this SVI as a default-gateway for clients.

On a layer 3 switch you can have multiple SVI's and the L3 switch will route between these vlans.

Jon

[mahesh18]

Hi Jon,

i was reading book of Oreilly,

It says that switch 6509 in hybrid mode.

2 vlans have been created on 6509

catos-6509> sh vlan shows

vlan name

1 default active status

10 lab vlan active status

20 vlan0020 active status

now i go to mfsfc mode

and config the SVI by

MSFC--6509# config t

MSFC--6509# int vlan 20

MSFC--6509# ip address 10.20.20.1 255.255.255.0

MSFC--6509# no shutdown

now i run this command

MSFC--6509# sh ip int brief

Vlan 20 10.20.20.1 down down

it says tin book that SVI will now come up

unless there is active por ton layer 2.

in book they have assign IP address to the

CatOS Management int SCO, and place i tin vlan 20.

CatOS-6509 set int sco 20 10.20.20.20 255.255.255.0

Can u please expalin me last part Catos ?Management inetrface SCO??????????????

i do not get that part

[Richard Burts]

Mahesh

In the Catos based switches the syntax does not support configuring interface vlan x as the management interface of the switch (that is more a mechanism of the IOS based switches). In the Catos based switches sc0 is the management interface for the layer 2 switch.

HTH

Rick

[mahesh18]

Hi rick

thanks for reply

can u explain me in more detail please

[Richard Burts]

Mahesh

A layer 2 switch will have a single virtual interface which is used to manage the switch. How the management interface is identified (and how it is configured) depend on the type of switch and what type of operating system it uses. In the example that you posted the switch is a 6500 switch and is running CatOS operating system. In these switches the management interface is called sc0.

In other switches (such as the 3550 in the example from Jon) the management interface is called interface vlan x

So sc0 is the management interface for a CatOS type of switch and interface vlan x is the management interface for an IOS type of switch.

HTH

Rick

[mahesh18]

Hi Rick,

thanks for reply

so we make SVI for vlan in MSFC side and assign it IP address and in order that vlan

should be UP UP we need to assign IP to Sc0 interface in MSFC and these two ips have to be different right one assigned to SVI and other assign to Sc0????

thanks

[Jon Marshall]

Mahesh

The sc0 interface has nothing to do with the MSFC. The MSFC on a 6500 is for routing and here is where you would create your L3 SVI's.

As Rick has stated sc0 is for managing a CatOS switch. It may help to clear up the difference between native and hybrid on a 6500.

Native mode means that the L2 switch and the L3 part (MSFC) are configured using just IOS. So if you wanted to assign a management interface to a 6500 in native mode you would use an SVI an assign it an address.

Hybrid mode means the L2 switch is running CatOS and the L3 part (MSFC) is running IOS. So if you wanted to assign a management interface to a 6500 in hybrid you use the sc0 interface in the CatOS configuration and assign an IP address to that.

Does this make sense ?

Jon