LAN/WAN Issue

Hi
Still haven't been able to sort this issue out..

I have the following Packet Tracer topology:

http://oi42.tinypic.com/nn44tg.jpg

The whole LAN network works perfectly, i have 4 different subnets configured and all of them are able to ping eachother across the Layer 3 switch. My issue is how do i connect the LAN to the WAN? On the router i have a loopback interface to simulate the internetwork.
I can't figure out how to make the different vlans able to ping the router, and the routers loopback interface.. I don't know what IP address to give to the fastethernet interface on the router and on the layer 3 switch in order for them to communicate..
All my vlans are numbered like this:
VLAN 10: 10.145.10.0
VLAN 20: 10.145.20.0
VLAN 30: 10.145.30.0
And so on.. But what IP address do i assign to the fastethernet interface connecting the router to the layer 3 switch? Do i create a whole new subnet and use two addresses on each side? Do i give them an IP Address within my management vlan? Or do i configure a default static route to the router on the layer 3 switch? I really need an explanation.. Thank you!

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Comments

iwannaknowIT

You will need to config router-on-a-stick(sub-interfaces) with each vlans' default-gw configed....and a routing protocol to advertise your loopback......

Dieg0M

CE and PE IP will be given by the ISP or generated by DHCP. You can simulate this with a simple /30 between your Multilayer Switch and the router. For example the interface IP between the router and the Multilayer switch can be 192.168.0.1/30 for the Multilayer switch and 192.168.0.2/30 for the router. After that, configure a default static route on the multilayer switch with: <ip route 0.0.0.0 0.0.0.0 192.168.0.2 <interface name>. Also don't forget to configure a static route back on the router and default-gateways on your l2 switches. For a router on a stick configuration you do not need a routing protocol because all the nodes will be C (directly connected) and you wont usually be sharing edge routing information with the provider. If you do share routing, it will usually be through BGP and only in cases of dual-homed edge connections for route manipulation.

iwannaknowIT

Dieg0M wrote: »

CE and PE IP will be given by the ISP or generated by DHCP. You can simulate this with a simple /30 between your Multilayer Switch and the router. For example the interface IP between the router and the Multilayer switch can be 192.168.0.1/30 for the Multilayer switch and 192.168.0.2/30 for the router. After that, configure a default static route on the multilayer switch with: <ip route 0.0.0.0 0.0.0.0 192.168.0.2 <interface name>. Also don't forget to configure a static route back on the router and default-gateways on your l2 switches. For a router on a stick configuration you do not need a routing protocol because all the nodes will be C (directly connected) and you wont usually be sharing edge routing information with the provider. If you do share routing, it will usually be through BGP and only in cases of dual-homed edge connections for route manipulation.

Thanks for the correction in my goof up......It's the lack of small details that'll drive admins crazy.....no routing protocols needed for C routes(or Lo int)

instant000

This seems to be what DiegoM proposed:
Create a layer 3 link between the 2811 and the 3560.
Add a route on the 3560, to default towards the 2811.
Add routes for all of your internal networks on the 2811, to point to the 3560.
Add default gateways on the L2 switches ...As you already have full reachability within your LAN, you should have already done this.

This is what iwannaknowIT proposed:
Configure router-on-stick with the 2811 serving as the default-gw for all of the layer 2. (this breaks your current design, as you already have the layer 3 switch providing this function)
Establish a routing protocol, to advertise the loopback on the router. (This is not necessary, as DiegoM pointed out, because if the default-gw is on the router, so is the loopback, and they're already directly connected, so there is no need for a routing protocol in order to have reachability.)

This is what I would have initially proposed:
Configure a layer 3 link between 2811 and 3560.
Configure a routing protocol between the 2811 and the 3560.

I think this is the best solution: What DiegoM said.

Why? Your question asked LAN/WAN.

Since your LAN was already working:

The whole LAN network works perfectly

We should have used that as a clue that you only had a WAN issue.

You even said this:

My issue is how do i connect the LAN to the WAN?

You then asked a lot of questions about how do you configure the router/switch to work effectively together. Based on your questions, the only link causing you issues is between the 2811 and the 3560.

DiegoM provided the only solution that addressed the WAN. He gets a cookie, and +rep. [Edit: You must spread some reputation around before giving it to DiegoM again.]

Thanks for asking this question. It will help me to read more carefully in the future.

TheNewITGuy

Since you have all your vlans setup and Im going to assume the gateway is on the 3560 - then all you need to do is route traffic to the 2811 from the 3560. Router on a Stick isn't needed since you have a Layer3 Switch.

theodoxa

You could enable IP Routing on the Catalyst 3560.