01-30-2007 01:56 PM - edited 03-05-2019 02:04 PM
I have a 3745 with a 34 port ethernet card.
I configure port 2/0 as a trunk. I create interface vlan 1 and assign it an IP and no shut.
Now, port 2/0 is a trunk and it's up. But why is interface vlan 1 showing "up, down"?
The trunk has native vlan set to 1 by default so - interface vlan 1 should be "up, up" but is isn't!
Anyone explain why?
01-30-2007 03:04 PM
You have a port on that ethernet card that is vlan 1 and is connected before the SVI will go up/up , once you get one port in vlan connected the SVI will go up/up.
01-30-2007 04:17 PM
Hello,
TO have SVI go up you have to have one of the below cases:
1- One interface assigned to the vlan and in UP/UP state
2- You have a trunk port in Up/UP state
You case matches number 2. However, issue the command "show interface trunk" to check if the port has negotiated as trunk. Also, make sure that the trunk interface is in UP/UP state.
You need to wait for about 15 seconds after the trunk is up so that the SVI goes up.
One last thing to check is that if you layer 2 switch you cann't have to SVIs with IP addresses assigned and UP. One of them showed only be up.
Let me know if one of the above solves your problem and appreciate your rating,
Regards,
01-30-2007 04:17 PM
Hello,
TO have SVI go up you have to have one of the below cases:
1- One interface assigned to the vlan and in UP/UP state
2- You have a trunk port in Up/UP state
Your case matches number 2. However, issue the command "show interface trunk" to check if the port has negotiated as trunk. Also, make sure that the trunk interface is in UP/UP state.
You need to wait for about 15 seconds after the trunk is up so that the SVI goes up.
One last thing to check is that if you layer 2 switch you cann't have TWO SVIs with IP addresses assigned and UP. One of them showed only be up.
Let me know if one of the above solves your problem and appreciate your rating,
Regards,
01-31-2007 04:49 AM
As you say in case 2, I should see the SVI up but it isn't. I think this is a bug because the trunk is up and all other tagged VLAN SVI's are up.
Only the native VLAN is not coming up but there is an interface up because the native VLAN port is up.
01-31-2007 05:17 AM
Maybe you can post the trunk setup on both sides . I doubt it is bug .
01-31-2007 10:19 AM
What type of Switch is it?
If it is L2 switch you can have ONE SVI up!
Regards,
01-31-2007 10:28 AM
Dave,
Do a 'show int (trunk_port) switchport' and check whether vlan 1 is allowed on the trunk. Sometimes, pruning (manual or vtp pruning) mightn't be forwarding data on a trunk for a certain vlan.
HTH
Sundar
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