question for the cisco heads

Bl8ckr0uter

Ok I am labbing right now. My lab consist of 1 1721 and 2 2950s for cisco testing and a netgear router for the internet. I have a windows server box with 3 nics: 1 connected to the switch A, 1 connected to switch b, and 1 connected to my netgear router for internet access. Port 1 is a 10.0.0. network (it is 10.0.0.47) and it is in vlan 2. Port b is in a 192.168.1 network and it is in vlan 3 (it is 192.168.2.65). I have set up dot1q trunking on my cisco router and everything is working now. My issue is that my router only has 1 ethernet port. I was thinking about changing my network up to being something like this:cable modem>1721>netgear box>2950>2950My concern is what will happen to the tagged frames when they hit the netgear box. If I configure vlans on the 2950s and set the 1721 as the default gateway would this work? What is this: Say I ping an ip address from my computer that is set in a different network. Like say I ping 192.168.1.47. What is happening is the icmp request are being sent out to the default gateway and then being sent by the other port, or in a sense it is being from the computer to the gateway, and then the computer replies (I have been watching this happen in wireshark). But when the information is sent out to the gateway, it is using a packet (layer 3) so what I think will happen is when the netgear gets a packet (lets just say in this case the icmp request) it will forward it on to the 1721 (after I set it up to do by setting the default gateway for the netgear router to be the 1721). The same thing should apply to the vlan traffic that is destined for intervlan communication (right?).I think my question makes sense (or at least it does to me). I also plan to try to use route redistribution from ospf or eigrp to rip (since my home router only supports rip v1). I think this might work but I am not sure about the vlan thing. Anyone care to help a brother out?

human151

If I understand your question correctly, sounds like you want inter vlan routing but are confused because your 1721 only has 1 FA port? You will need to set up sub interfaces f0/0.1 .2 etc.. DO not put the ip addy on the actual interface. Put the Adress/SM on the subinterfaces and advertise both networks and it should work. Its called router on a stick.

Bl8ckr0uter

What I meant is in a topology like this:



1721<netgear<2950<2950


Would my Vlans still be able to ping each other.

I do understand router on a stick and 802.1q. I am just not sure where in this process it the information would be come an actual packet. Because if it isn't a packet until it hits the default gateway then this won't work but if it is a packet before that then this would work.

Say a host in Vlan 1 pings a host in Vlan 2 in my topology, would they be able to resolve.

billscott92787

I think human is right. I mean you have to have ROAS configured if you are able to communicate between the different VLANs.

Are you asking if you can connnect your 1721 to your Netgear, and then your 2950's into the netgear and still be able to send VLAN traffic? between everything? If so, you'd have to configure 802.1Q on the netgear. But the topology really wouldn't make any sense. Why would you want your switches to send frames to the netgear, then to the 1721 then back to the netgear, then back to the switches?

Bl8ckr0uter

billscott92787 wrote: »

I think human is right. I mean you have to have ROAS configured if you are able to communicate between the different VLANs.

Are you asking if you can connnect your 1721 to your Netgear, and then your 2950's into the netgear and still be able to send VLAN traffic? between everything?

Yep. I have roas stick enable and again everything is working right now.

As far as why, simply because I want to practice routing protocols AND I want vlan traffic on my network.

What I could do is just put everything in 1 vlan and then all would be well but that would be to simply

The big issue is that the netgear really isn't a true router, and all ports on the netgear are in the same network. Because also what I could do is set each port on the netgear to be the default gateway for a vlan. Kinda of like a physical implementation of router on a stick but idk if this is going to work.

EdTheLad

knwminus wrote: »

The big issue is that the netgear really isn't a true router, and all ports on the netgear are in the same network. Because also what I could do is set each port on the netgear to be the default gateway for a vlan. Kinda of like a physical implementation of router on a stick but idk if this is going to work.

The questions you need answered are:
1) How do the ports on the netgear work, are they working as a hub or a switch.
1) If they work as a switch do the ports support dot1q frames.If they don't anything coming in tagged will be discarded.If they do support dot1q then you should be able to play with different setups.

Bl8ckr0uter

EdTheLad wrote: »

The questions you need answered are:
1) How do the ports on the netgear work, are they working as a hub or a switch.
1) If they work as a switch do the ports support dot1q frames.If they don't anything coming in tagged will be discarded.If they do support dot1q then you should be able to play with different setups.

That is exactly right. I just wanted to see if anyone knew off the cuff. I will lab it out and I will know pretty quickly if it doesn't work