Inter VLAN Routing.

Hi,
I have one cisco 2950 XL switch (Model WS-C2950) and one cisco 2621XM
Router. I want to configure 4 VLAN on that switch and configure
interVLAN Routing on that router. I will use 802.1q for trunking.
Is it posible. If yes, can any one send me a sample configuration.

~MS

 

Yes it is possible, here is a sample config using FA 0/5 as the trunk port
and all vlans are allowed through the trunk up to the router. I made vlans
10, 20, 30, 40.

vlan database
vtp server
vtp domain [name of your vtp domain]
vlan 10 name vlan1
vlan 20 name vlan2
vlan 30 name vlan3
vlan 40 name vlan4
exit
!
config t
!
hostname DistributionSwitch1
!
interface FastEthernet0/1
description Link to vlan 10 (Host)
switchport access vlan 10
switchport mode access
no ip address
no shut
!
interface FastEthernet0/2
description Link to vlan 20 (Host)
switchport access vlan 20
switchport mode access
no ip address
no shut
!
interface FastEthernet0/3
description Link to vlan 30 (Host)
switchport access vlan 30
switchport mode access
no ip address
no shut
!
interface FastEthernet0/4
description Link to vlan 40 (Host)
switchport access vlan 40
switchport mode access
no ip address
no shut
!
interface FastEthernet0/5
description Trunk to router
switchport trunk encapsulation dot1q
switchport mode trunk
no ip address
no shutdown
!
interface Vlan1
description MANAGEMENT VLAN
ip address 10.0.1.1 255.255.255.0
no shut

interface Vlan10
ip address 10.0.10.1 255.255.255.0
no shut
!
interface Vlan20
ip address 10.0.20.1 255.255.255.0
no shut
!
interface Vlan30
ip address 10.0.30.1 255.255.255.0
no shut
!
interface Vlan40
ip address 10.0.40.1 255.255.255.0
no shut

Then on the actual hosts, make sure their ip addresses are in the vlan
network you specified on the switch.

Bring up your ethernet interface connected to the switch, make sure it is up
and you can see the switch in cdp neighbors.

The router will need to have a routing protocol, say OSPF, running on the
network of the vlans you want to route.

router ospf 200
network 10.0.0.0 0.255.255.255 area 0
exit

I believe that is all you need unless I am forgetting something at the
moment. Let me know how this goes.

-John

 

Hi,

First of all, you need IP Plus featurepack on the 2621XM router to support
trunking.

Configure the following on the switch:

interface fastethernet 0/1
speed 100
duplex full
switchport mode trunk
!
interface fastethernet 0/2
switchport access vlan 1
!
interface fastethernet 0/3
switchport access vlan 2
!
interface fastethernet 0/4
switchport access vlan 3
!
interface fastethernet 0/5
switchport access vlan 4
!

On the router configure:

interface fastethernet0/0
speed 100
full-duplex
no ip address
!
interface fastethernet0/0.1
encapsulation dot1q 1 [native]
ip address 10.0.1.0 255.255.255.0
!
interface fastethernet0/0.2
encapsulation dot1q 2
ip address 10.0.2.0 255.255.255.0
!
interface fastethernet0/0.3
encapsulation dot1q 3
ip address 10.0.3.0 255.255.255.0
!
interface fastethernet0/0.4
encapsulation dot1q 4
ip address 10.0.4.0 255.255.255.0
!

And you should be fine

Erik

 

No need for that. Static routing works fine too.

You need a subinterface for each VLAN configured on the router's
Ethernet interface, with the appropriate "encapsulation" command.
And the router must run an IP Plus image to begin with.

 

You're sure that this is still speaking of a 2950? I'm doing this all
the day on 3550s, 3750s, Cat4ks with SupIV and Cat6ks with MSFC2, but
I was under the impression that 2950s - even the EI ones - just choke
when given "ip routing" or more than one EtherSVI "vlan x" commands.
They are L2 switches, after all. But if I'm missing something and there
are 2950s that actually can route, please detail. Would be a bargain.

Making the 2621 a "router on a stick", using one trunk to the switch,
as already described in the other followups, is IMO the only solution
as long as the 2950 didn't become an L3 switch over night (which may
happen, as I neither know the exact ASICs they use nor the exact plans
Cisco have for their IOS an that platform).

 

default-gateway

Anyone plz. tell me, y default-gateway is not configured on the switch. i'm reading cisco press icnd1, he writes this command in Global config mode "ip default-gateway a.b.c.d".
thanks.