How to Use Switch Layer 2 Ports on Cisco 1841 Router

atifmasood

Hi

I am using Cisco 1841 Router with only one Layer 3 Fe0 port and 8 Switch Ports.

I have given IP on Fe0 port which is connected to another router.

Now I don't know how to use the Switch Layer 2 ports of the router.

I have tried making one of the port as Access Port by switchport mode access and connected my laptop and given IP of the same subnet but I am unable to ping my Fe0 port IP and vice versa as I am also unable to ping my Laptop from Router.

Deathmage

are you using a straight-through or a crossover cable?

atifmasood

Well I believe its straight through. but does it matter now a days?

Also I fixed the problem. I just created a vlan in vlan database and assigned ip to it and assigned that vlan to L2 port. Now I am able to communicate between both interfaces.

networker050184

The switch module and routed port aren't tied together. You need to build an SVI (on another subnet) for the switch ports use as a gateway and it will route to the L3 port.

theodoxa

Switchports on a router work like a Layer 3 Switch. You create an SVI ("interface vlan x") and assign an IP Address to it. You would then assign switchports to the VLAN and make the IP Address you assigned to the SVI the default gateway for your PCs.

Simrid

atifmasood wrote: »

Well I believe its straight through. but does it matter now a days?

Also I fixed the problem. I just created a vlan in vlan database and assigned ip to it and assigned that vlan to L2 port. Now I am able to communicate between both interfaces.

In the more recents routers and switches, they can use auto sence allowing them to adapt the type of cable being used. I believe, the 1841 switch is an older switch that does not have this feature.

Hondabuff

Router#sho ip int b Interface IP-Address OK? Method Status Protocol

FastEthernet0/0 unassigned YES unset administratively down down

FastEthernet0/1 unassigned YES unset administratively down down

FastEthernet0/0/0 unassigned YES unset up down

FastEthernet0/0/1 unassigned YES unset up down

FastEthernet0/0/2 unassigned YES unset up down

FastEthernet0/0/3 unassigned YES unset up down

FastEthernet0/1/0 unassigned YES unset up down

FastEthernet0/1/1 unassigned YES unset up down

FastEthernet0/1/2 unassigned YES unset up down

FastEthernet0/1/3 unassigned YES unset up down

Vlan1 unassigned YES unset administratively down down
Router#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#int vlan 2

Router(config-if)#ip address 192.168.1.1 255.255.255.0
Router(config-if)#no shut
Router(config-if)#ex

Router(config)#int range fastEthernet 0/0/0 - 3

Router(config-if-range)#switchport mode access



Router(config-if-range)#switchport access vlan 2
% Access VLAN does not exist. Creating vlan 2
Router(config-if-range)#
%LINK-5-CHANGED: Interface Vlan2, changed state to up


%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0/0, changed state to up


%LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan2, changed state to up