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New Member

VLan setup for a 2950 and 2611

Im trying to setup a real basic VLan setup for 1 2950 switch. I would like to have 3 Vlans on it including the default Vlan. So my understanding is that for all 3 of the VLans to talk to each other I will need a router to be the layer 3 device that routes the Vlans.

On my 2611 it looks like this:

!

interface Ethernet0/0

no ip address

full-duplex

!

interface Ethernet0/0.1

encapsulation dot1Q 1 native

ip address 172.16.10.1 255.255.255.0

no snmp trap link-status

!

interface Ethernet0/0.2

encapsulation dot1Q 2

ip address 172.16.20.1 255.255.255.0

no snmp trap link-status

!

interface Ethernet0/0.3

encapsulation dot1Q 3

ip address 172.16.30.1 255.255.255.0

no snmp trap link-status

!

Then my 2950 looks like this:

!

interface FastEthernet0/1

description Connection to router

switchport mode trunk

speed 10

duplex full

!

interface FastEthernet0/2

switchport access vlan 2

!

interface FastEthernet0/3

switchport access vlan 3

!

!

!

interface Vlan1

ip address 172.16.10.2 255.255.255.0

no ip route-cache

!

ip default-gateway 172.16.10.1

!

Ok so as it currently stands the switch and router will not talk to each other at all. From the switch I can not ping the router and vice a versa. If I plug a laptop into one of the ports using VLan1 I can ping the switch IP 172.16.10.2 but obviously can not ping the default gateway which is the router...

I didnt think this looked very hard but for some reason it does not want to work for me at all...

Any ideas?

LR

  • Other Network Infrastructure Subjects
12 REPLIES
VIP Purple

Re: VLan setup for a 2950 and 2611

Hello,

are you using a straight cable for the connection between the switch and the router ?

Regards,

GP

New Member

Re: VLan setup for a 2950 and 2611

Yes I am using a straight cable. I just tried a cross-over cable and then I dont get any link activity.

Any other things you can think of to try?

Thanks,

LR

New Member

Re: VLan setup for a 2950 and 2611

Routers require a FastEthernet interface to support trunking. The router you are using has an Ethernet interface.

New Member

Re: VLan setup for a 2950 and 2611

Not to disagree but I found the following article on ciscos website and I think it is telling me I can trunk 8021Q over an ethernet interface...

http://www.cisco.com/en/US/products/hw/routers/ps259/prod_bulletin09186a00800921e4.html

Am incorrect in assuming this?

Thank you,

LR

New Member

Re: VLan setup for a 2950 and 2611

According to that document you are correct. Are you running 12.2(2)T or newer? Your config looks good.

Verify the switch is trunking on that port and that STP has not blocked the VLANs.

sh spanning-tree interface f0/1

sh interfaces trunk f0/1

New Member

Re: VLan setup for a 2950 and 2611

2611 IOS Version 12.3(17a).

I ran those 2 commands and get the following output:

2950C#sh interfaces trunk

Port Mode Encapsulation Status Native vlan

Fa0/1 on 802.1q trunking 1

Port Vlans allowed on trunk

Fa0/1 1-4094

Port Vlans allowed and active in management domain

Fa0/1 1-3

Port Vlans in spanning tree forwarding state and not pruned

Fa0/1 1-3

2950C#sh spanning-tree interface f0/1

Vlan Role Sts Cost Prio.Nbr Type

---------------- ---- --- --------- -------- --------------------------------

VLAN0001 Desg FWD 100 128.1 P2p

VLAN0002 Desg FWD 100 128.1 P2p

VLAN0003 Desg FWD 100 128.1 P2p

Is there anything else I could provide that might make this easier to diagnose?

Thanks for all of the help,

LR

New Member

Re: VLan setup for a 2950 and 2611

The previous output commands show that VLAN 1 is the native VLAN on the switch port. If you do a "show ip interface brief" on the router are all of the sub-interfaces up?

Purple

Re: VLan setup for a 2950 and 2611

On the 2950 did you create the layer 2 vlans for vlan 2 and 3 ? Do a "show vlan" on the 2950 and see if vlan 2 and 3 show up ? If not you must create them before the other 2 vlans will work . The rest of the config looks ok . If you do a "show int trunk" on the 2950 does it show trunking ??

New Member

Re: VLan setup for a 2950 and 2611

2950C#show vlan

VLAN Name Status Ports

---- -------------------------------- --------- -------------------------------

1 default active Fa0/4, Fa0/5, Fa0/6, Fa0/7

Fa0/8, Fa0/9, Fa0/10, Fa0/11

Fa0/12, Fa0/13, Fa0/14, Fa0/15

Fa0/16, Fa0/17, Fa0/18, Fa0/19

Fa0/20, Fa0/21, Fa0/22, Fa0/23

Fa0/24

2 Sales active Fa0/2

3 Marketing active Fa0/3

1002 fddi-default act/unsup

1003 token-ring-default act/unsup

1004 fddinet-default act/unsup

1005 trnet-default act/unsup

VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2

---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------

1 enet 100001 1500 - - - - - 0 0

2 enet 100002 1500 - - - - - 0 0

3 enet 100003 1500 - - - - - 0 0

1002 fddi 101002 1500 - - - - - 0 0

1003 tr 101003 1500 - - - - - 0 0

VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2

---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------

1004 fdnet 101004 1500 - - - ieee - 0 0

1005 trnet 101005 1500 - - - ibm - 0 0

Remote SPAN VLANs

------------------------------------------------------------------------------

Primary Secondary Type Ports

------- --------- ----------------- ------------------------------------------

2950C#show int trunk

Port Mode Encapsulation Status Native vlan

Fa0/1 on 802.1q trunking 1

Port Vlans allowed on trunk

Fa0/1 1-4094

Port Vlans allowed and active in management domain

Fa0/1 1-3

Port Vlans in spanning tree forwarding state and not pruned

Fa0/1 1-3

To me it looks right, but then again this is the first time I have ever tried to setup a Vlan... So in my mind I keep thinking I must be missing somthing really simple. Like the interface is shutdown or somthing dumb like that...

LR

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