Sharing Internet Link

Unanswered Question
Jan 2nd, 2007
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Dear All,

We want to share our head office internet link with regional office users.

Existing Setup at head office = Internet Lease Link with bandwidth = 2Mbps over Ethernet interface.

Proposed setup = Additional point to point link between head office and regional office over ethernet.

Requirement = Serve internet to regional office lan users from head office internet pipe using subinterface on the internet router at head office and natting the regional office lan.

Do we need to enable dot1q on the switch where the regional office point to point link will terminate.

Pls suggest.


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network.king Tue, 01/02/2007 - 22:09
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Hi ,

If you have multiple regional offices to be terminated on the switch and going to have a trunk to the router for L3 termination , then dot1q needs to be enabled in your switch and your router sub-interfaces for correspodning vlans

on switch :

switchport trunk encapsulation dot1q

switchport trunk allowed vlan x,y...

on router :

int fa0/0.1 --- 1st regional office

encapsulation dot1q x

ip address

int fa0/0.2 --- 2nd regional office

encapsulation dot1q y

ip address

Hope this helps.


vanesh k

fmatrine Tue, 01/02/2007 - 22:17
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What if the switch is not supporting vlan and is unmanaged switch.

network.king Tue, 01/02/2007 - 22:35
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Hi ,

If your switch us a unmanaged one , then you can have one point to point link on the default vlan , no sub-interfaces required and no trunk , need to make sure your Ethernet provider would give a Ethernet link without any Vlan specification.

If you require another point to point link , its not possible.

Hope this helps


vanesh k

jackyoung Wed, 01/03/2007 - 00:05
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In addition to Vanesh's post, I assume your PTT support VLAN, so you can enable two VLAN (one for Internet & one for remote office).

Then you have to use the Internet router to carry the routing between VLANs.

At the remote office, it depends on the PTT that it may not require a VLAN supported LAN switch.

You better check w/ local PTT what they can provide and their limitation on the Metro Ethernet service.

Hope this helps.


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