Cisco 2821 How to create VLANS ?

Unanswered Question
Feb 20th, 2007

Hi,

Real stupid question for me but I have to ask. I have a Cisco 2821 unit and I'm trying to create vlans; non of the normal commands (set vlan, int vlan etc) are accessible. I can access the vlan database and set names, but no ip's etc?

The unit is a cisco 2821 with a NME-16ES-1G-P card with IOS 12.4(2)T5

Any pointers would be much appreciated.

Thanks

Ed

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sundar.palaniappan Tue, 02/20/2007 - 11:09

Ed,

I assume you want to configure VLAN interfaces, aka SVIs, to route traffic between the VLANs. In that case, try this;

int

encapsulation 1 --> where 1 is VLAN1. Set the encap to dot1q or ISL based on what trunking encap is set on the switch the interface is connected to.

ip address x.x.x.x/xx

int

encapsulation 2 --> where 2 is VLAN2.

ip address x.x.x.x/xx

Instead, if you had a different requirement can you clarify what exactly you want to do and we may be able to help you.

HTH

Sundar

edw Tue, 02/20/2007 - 12:35

Hi,

Thanks for the reply. I used to use set vlan commands. New to the whole 12.4 stuff. which f0/0.1 interface is it to config ? surely I should be using interface vlan 1 etc ??

I am simply trying to create a set of vlans on the router to use on the switches connecting to it.

Thanks

Ed

sundar.palaniappan Tue, 02/20/2007 - 12:45

Add the VLANs from the VLAN database. The output below is from a 3725 router. I am sure the command structure on a 2800 is similar to this one.

R5#vlan data

R5(vlan)#vlan 5 name test

VLAN 5 added:

Name: test

R5(vlan)#apply

APPLY completed.

R5(vlan)#show

VLAN ISL Id: 1

Name: default

Media Type: Ethernet

VLAN 802.10 Id: 100001

State: Operational

MTU: 1500

Translational Bridged VLAN: 1002

Translational Bridged VLAN: 1003

VLAN ISL Id: 2

Name: VLAN0002

Media Type: Ethernet

VLAN 802.10 Id: 100002

State: Operational

MTU: 1500

VLAN ISL Id: 5

Name: test

Media Type: Ethernet

VLAN 802.10 Id: 100005

State: Operational

MTU: 1500

HTH

Sundar

edw Tue, 02/20/2007 - 13:10

Hi,

Thanks - but how do I then assign the ip address for vlan gateway ? IE for gateways for the PCs on the vlan etc ?

Thanks

Ed

sundar.palaniappan Tue, 02/20/2007 - 13:21

There are two ways you can configure a router/layer 3 switch to route traffic between VLANs. You can configure VLAN interfaces, aka SVIs, if your router supports it. The command to configure SVI is 'int vlan (#)' from the config mode. Or, if the router doesn't support SVIs then you need to configure sub-interfaces like I had mentioned in my previous posting.

HTH

Sundar

edw Tue, 02/20/2007 - 15:26

Hi,

Thanks for the help. WHat Im finidng difficult is where do I assigned the ip for the vlan itself. The email re int fa0/0.1 - doesnt this mean im assigning a ip address to the port rather than the vlan ?

Thanks

Ed

sundar.palaniappan Tue, 02/20/2007 - 15:47

You don't assign an IP to the VLAN itself. When you create a VLAN from the VLAN database mode all you are doing is making the switch aware of a broadcast domain. Then, you assign switch (layer2) ports to that VLAN. To route traffic between the VLANs you need a layer 3 interface, like SVI or sub-int, and that's where you apply the IP address. Hope I made it clear.

HTH

Sundar

edw Tue, 02/20/2007 - 16:56

Hi,

Thanks again - yep understand that. Ive being using C6006 Routers so used to the set vlan command structure.

The bit I'm mis understanding is the sub-int part - which interface should the vlan be under IE my 2821 unit has two gigabit ports and also a 16 port netowrk module which is viewed as another gigabit port... so where do I configre the vlans as sub interfaces ??

Thanks

Ed

edw Wed, 02/21/2007 - 05:19

Hi,

Thanks - Im having a problem with VTP now thou - I have configured the Giga1/0 as vlan 1 with ip and then 1/0.1 as vlan 2.

Set the router to server with domain name and then swtich card to client with domain name and its not proagating ??

Help im confused - dont have this problem on my boxes - why does cisco change the commands for the SMB boxes - its pointless..

Thanks

Ed

edw Wed, 02/21/2007 - 05:54

Well, unfortantly if I don't the switch doesnt work and I can access the switch IOS in on the card ????? Then when I try to apply another ip on the vlan 1 range it complaines its overlapping ??

Using 1219 out of 245752 bytes

!

version 12.4

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname R-CORE-01

!

boot-start-marker

boot-end-marker

!

enable secret 5 $1$YOGa$gQdMjrhxhzHFVbHZ1RI9j1

enable password Mother2

!

no aaa new-model

!

resource policy

!

ip subnet-zero

!

!

ip cef

no ip dhcp use vrf connected

!

!

!

!

!

!

interface GigabitEthernet0/0

ip address 192.168.1.1 255.255.255.0

duplex auto

speed auto

vlan-range dot1q 1 3

exit-vlan-config

!

!

interface GigabitEthernet0/1

no ip address

shutdown

duplex auto

speed auto

!

interface GigabitEthernet1/0

no ip address

no mop enabled

!

interface GigabitEthernet1/0.1

encapsulation dot1Q 1 native

ip address 10.1.1.254 255.255.255.0

no snmp trap link-status

!

interface GigabitEthernet1/0.2

encapsulation dot1Q 3

ip address 10.3.1.254 255.255.255.0

no snmp trap link-status

!

ip classless

!

no ip http server

!

dialer-list 1 protocol ip permit

!

I have connected a switch to the gi0/0 port as well and VTP is not sync with that oe either ???

VTP Version : 2

Configuration Revision : 2

Maximum VLANs supported locally : 48

Number of existing VLANs : 13

VTP Operating Mode : Server

VTP Domain Name : JOY

VTP Pruning Mode : Disabled

VTP V2 Mode : Enabled

VTP Traps Generation : Disabled

MD5 digest : 0x11 0x3F 0xA6 0xF3 0xDF 0x2C 0xCF 0x1B

Configuration last modified by 10.1.1.11 at 2-21-07 13:09:48

Local updater ID is 192.168.1.1 on interface Gi0/0 (first interface found)

Thanks

Ed

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