SVI Creation Prerequsites

Unanswered Question
Dec 22nd, 2008
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ISR 2821, IOS packaging is SPServ. Have a pretty but important to me question.


(conf)# int ? <!--- want to check is there 'vlan' int is available

... there is no Vlan in the ouput ...


What conditions must be met/configured before SVI (switched virtual interface) would be allowable to create ?

Thank you.

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Overall Rating: 3 (2 ratings)
mahmoodmkl Mon, 12/22/2008 - 23:15
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Make sure that u have vlan created at L2 before u create SVI.



Tobivan_Helden_2 Tue, 12/23/2008 - 00:00
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Is it possible to create L2 vlan on the ISR ?

I always think the undermentioned functionality


#conf t

(conf)# vlan

(conf-vlan)# name


is only available on switches ?

mahmoodmkl Tue, 12/23/2008 - 00:09
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I think i mis-interpret u r question.

I dnot think u can create the L2 vlan on this router.

I assume u r thinking of crreating the sub-interfaces...?

Please elaborate.



glen.grant Tue, 12/23/2008 - 04:23
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That command is there if you happen to install one of the 4,8 or 16 port switchcards into the chassis, then you create the SVI's for that switchcard as you would for any layer 3 switch . Its of little use if you don't have a switchcard installed.

Richard Burts Tue, 12/23/2008 - 05:09
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Perhaps I am not clear about what you are attempting to accomplish. If your interpretation of SVI is specificcally to create a "VLAN" interface then Glen is correct that the only way to create a VLAN interface on the 2821 router is to have a switch module installed. But another possible interpretation of SVI is the ability to communicate with VLANs running on a switch. In that case you can configure the Ethernet interface(s) for trunking by configuring subinterfaces and assigning VLANs to the subinterfaces. It might look something like:

interface gig0/0.15

encapsulation dot1q 15

ip address x.x.x.x

interface gig0/0.22

encapsulation dot1q 22

ip address y.y.y.y

If I have not correctly understood what you are trying to accomplish then perhaps you can clarify for me.




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