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VLAN ID ? - changed the VLAN from A to B but the VLAN ID stayed on A?

Hi - im missing something basic here

Im telneted to a  nortel switch that had a cross ove rconnected to another nortel. I replaced this other/2nd nortel with a cisco 2950. the uplink between the 2 was originaly just on 1 vlan - and all was well. Problem was I wanted to telnet to the new cisco and couldnt as my pc was on different vlan that the new cisco. so i placed the uplink between the two onto BOTH VLANs - and yes i could then telnet to the new cisco. problem was that some remote offices whos links are on the nortel started to get some latency/dropped packets connections.

I changed the uplink between the two back to just the one original VLAN it was on. - yet still some dropped packets/remote office issues. - i just noticed though that even though the vlan was changed  - the  default vlan ID of the uplink port was still set at the new VLAN - so it had a mismatch between the VLAN it was on and its default VLAN ID? - I dont know hwy/how? what this means ? - But i set the VLAN ID to match the VLAN its on - and now it seems fixed i think - pings to remote offices are now consistent 1ms - i guess im asking about the VLAN ID mismatch - so what VLAN was the  port on the ID? or the VLAN? hope i havent been to confusing - why when i change the VLAN does the default VLAN ID not change as well?
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philb19
Asked:
philb19
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1 Solution
 
anoopkmrCommented:

Default vlan id will not cahnge automatically in  nortel switches , unless you enabled the vlan config-controll  autopvid.

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philb19Author Commented:
hi anoopkmr thanks - only reply :(

so does this mean even though i changed the vlan the port was on - the VLAN of the port did not really change until i changed the VLAN ID as well to match?
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anoopkmrCommented:

yes  other wise you have to enable the  autopvid option.. then it will immediately change once adding the  vlan to port.
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meraj11Commented:
Philb - You will have to read the following to understand it clearly. Anoop has briefly spoken to u about Auto PVID. Below gives u the complete details

Nortel has a feature called VLAN config control, I am assuming you are running 3.7 upwards software ...

VLAN Configuration Control offers four options for controlling PVID
modification:

• Strict: With the Strict option, an untagged port can only belong to one
VLAN. This option restricts you from adding an untagged port to a VLAN
if the port is already a member of another VLAN. To add an untagged
port to a new VLAN, you must first remove the port from all other VLANs
of which it is a member. The PVID of the port is changed to the VID of
the new VLAN to which it is added.
Note: The default VLAN Configuration Control setting is Strict.

• Automatic: This option is similar to the Strict option in that an untagged
port can only belong to one VLAN. However, when you add an untagged
port to a new VLAN, it is automatically removed from any previous VLAN
membership. The PVID of the port is automatically changed to the VID
of the VLAN to which the port now belongs. Since the port is first added
to the new VLAN and then removed from any previous membership, the
Spanning Tree Group participation of the port is not disabled as long as
the VLANs involved are in the same Spanning Tree Group.

• AutoPVID: This option functions in the same manner as previous
AutoPVID functionality. When an untagged port is added to a new
VLAN, the port is added to the new VLAN and the PVID is changed to
the VID of the new VLAN. The port is not removed from any previous
VLAN memberships. Using this option, an untagged port can have
membership in multiple VLANs.

• Flexible: This option functions in the same manner as disabling
AutoPVID functionality. When this option is used, PVID and tagging are
completely independent of each other, and there are no restrictions
on the number of VLANs to which an untagged port can belong. Any
new additions of an untagged port to a new VLAN does not change
the PVID of that port.

VLAN Configuration Control considerations
When setting VLAN Configuration Control, be aware of the following:
• When the Flexible option is selected, the AutoPVID feature is
automatically disabled.
• When the AutoPVID, Automatic, or Strict options are selected, the
AutoPVID feature is automatically set to enabled.
• When VLAN Configuration Control is enabled, the configuration is only
applied to ports with the tagging modes of Untag All and Tag PVID
Only. Ports with the tagging modes of Tag All and Untag PVID Only are
not governed by VLAN Configuration Control. Ports with the tagging
modes of Tag All and Untag PVID Only can belong to multiple VLANs
regardless of VLAN Configuration Control settings and must have their
PVID manually changed.
• If VLAN Configuration Control is set to Strict and a tagged port is a
member of multiple port-based VLANs, you cannot set the port to
untagged.
• If VLAN Configuration Control is set to Automatic and you set a tagged
port to untagged, the port is removed from all port-based VLANs.
• If VLAN Configuration Control is set to Strict or Automatic and you
remove a port member from a VLAN, the PVID for that member remains
unchanged.
• If VLAN Configuration Control is set to Strict or Automatic, you cannot
disable the AutoPVID feature.
• If VLAN Configuration Control is set to AutoPVID and you disable the
AutoPVID feature, the VLAN Configuration Control setting is updated
to Flexible.

Hope this answers your question.
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