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VLAN Tagging and Member set

Hi all,

Does the switch be able to tag any untagged traffic with VLAN ID (let say 500) and allow tagged traffic with VLAN ID (let say 600) in the same interface? if so, how?

Also, I would like to know what is the defferent between Normal-Range and Extended-Range VLANs? and Does both of them support VLAN dot1Q Tagging?

Also, What is EI and SI in L2 switches?

Thanks in Advance.


Re: VLAN Tagging and Member set


Trunks carry the traffic of multiple VLANs over a single link and allow you to extend VLANs across an entire network. 802.1Q does not tag frames on the native VLAN. It tags all other frames that are transmitted and received on the trunk. When you configure an 802.1Q trunk, you must make sure that you configure the same native VLAN on both sides of the trunk.

NOTE: By default, VLAN 1 is the native VLAN.

The normal VLAN range is 1-1005 and the extended is 1006-4094.

The switch must be in VTP transparent mode when you create extended-range VLANs. (VLAN IDs 1006-4094). And remember that to create the extended range VLAN we can't use vlan database mode, and we must use configuration mode on platforms that supports both methods.

802.1.Q supports both ranges, while ISL AFAIK supported only the normal range (it might be updated).

HTH, please do rate all helpful replies,

Mohammed Mahmoud.

New Member

Re: VLAN Tagging and Member set

Thanks Mohammed,

Appriciate your reply.

what I knew is that trunk does not tag any traffic it allows to pass the tagged traffic! what I need to acheive is to trunk any traffic tagged with VLAN ID (let say Voice) and tag any other untagged traffic with VLAN ID (Data).

Re: VLAN Tagging and Member set


No, trunk traverse all VLAN traffic other than the Native VLAN (VLAN 1 by default) tagged, by just configuring trunking all VLAN traffic is tagged on the trunk except for the Native VLAN which are sent untagged, and AFAIK you can't change the tag on a frame traversing the trunk.

As for the SI and EI issue in some L2 Cisco switches models:

SI = standard software image and EI = enhanced software image.

AFAIK the version of software depends solely on the model of switch, with no upgrade capabilities.

The SI version supports basic Cisco IOS functionality, Fast Ethernet connectivity, and cluster management.

The EI version supports all that and more. The EI version supports advanced intelligent services, gigabit connectivity, and a richer set of features. These include Cisco Spanning-Tree Protocol enhancements for high availability, access control parameters (ACPs) for enhanced security, and Differentiated Services Code Point (DCSP) and rate limiting for advanced quality of service.

HTH, please do rate all helpful replies using the scroll box on the right,

Mohammed Mahmoud.