Access port configuration (tag)

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Nov 18th, 2007
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Can anybody explain if two switch cascade with access port .

And any frames comes to first switch and move for 2nd one will tag remove and tag will again impose after enter to 2nd switch access port .

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Jon Marshall Sun, 11/18/2007 - 02:39
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If a tagged frame enters the first switch and the tag is the same vlan as the access ports that connect the 2 switches then the frame will be forwarded across to the second switch eg.

switch1 and switch2 are connected by an access port that is in vlan 2.

switch1 also has a a trunk link to another switch. Switch1 receives a tagged frame for vlan 2 and the port it is destined for is on switch2. Switch1 will strip the tag and send down the access port to switch2.

If switch receives a tagged frame that is not tagged with vlan 2 it would not send it down the port.



sanjoy2006 Sun, 11/18/2007 - 03:59
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Jon Thanks for reply.

This above query related with one problem I need solution for that I just explaining.

3750Sw1 ->3750sw2->2950sw1



Above the scenario one 3750sw1 connected with 7200 router vlan1 ip is

next 3750sw2 connected with 3750sw1 with trucking mode and gateway is another 3600 router .

Now I have a pool of vlan15

in 3750sw1 which is my ip-phone pool .

Individual 2950 running different vlan such as 5,6,7

If I want to connect a ip phone with 2950 switch how I will forward tag vlan 15 so that my first 3750sw1 can learn.

glen.grant Sun, 11/18/2007 - 04:37
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Just make sure vlan 15 is trunked to 3750 Sw2 and then trunk 15 along with whatever other vlans are needed on the 2950 for users . John had good explanation in his note , if vlan 15 is allowed in the trunk down to the 2950 if the phone makes request for an address then at the 2950 then the 2950 will tag the frame as vlan 15 (in a trunked setup) and forward to 3750 sw2 , 3750 Sw2 will do the same and forward to 3750 Sw1 who is handing out the addresses . Just setup a trunk between the 2950 and 3750 sw2 with vlan 15 allowed across the trunk. This is based on not really knowing how 3750 sw2 is setup, is it routing or just a layer 2 setup .

3750sw1-->trunk vlan 15-->3750sw2---trunk vlan15--->2950 .


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