subinterfaces

[cfajardo1_2]

I need 12 Vlans with with just 1 to 4 users in each vlan to access lanX so i was thingking of just using a 1700 series router. My problem is iam not sure whether this router can have as much as 12 sub-interfaces. If not, could anyone suggest any solution?

12vlans-----e/0(1721)e1-----lanX

thanks.

[spremkumar]

Hi

In case of going on for a Cisco 1700 router make sure your ios supports 802.1q encapsulation.

In general u need to have ip plus image in your router to have the support for different encapsulation..

Better you can look out for a switch and trunk them onto other ethernet port connecting to the other lan..

regds

[ankbhasi]

Hi Friend,

Yes this router will support 12 sub-interfaces.

http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_tech_note09186a0080094322.shtml#max_no_interfaces

You need to have minimum IP PLus feature to have support of encapsulation dot1q command working on subinterfaces.

HTH

Ankur

[cfajardo1_2]

the 12 vlans doesnt have to talk to each other..selected host just have to be routed to lanX. do i still need ios plus in this case?

Now i was thingking of going to 1800..but iam not so sure about the ios also.

[ankbhasi · Accepted solution]

Hi Friend,

Yes you still need a minimum of IP Plus feature and then only you will be able to configure subinterfaces on router and configure encapsulation command under every subinterface so that router can support traffic coming from different vlans on switch.

And once done you can configure proper ACLs under every subinterface to restrict traffic from each vlan not to talk to other vlan. You need not invest of 1800 router when you already have 1700 which supports your requirement.

HTH

Ankur

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