frame-relay DTE to DCE

I have a few questions related to each other.

My home frame relay lab has a 2621 router with 4 serial ports that I am using as the Frame Relay switch. The DCE side of the serial cables are plugged in here.

I then have 2 cisco 1721 routers hooked into the 2621

question 1, I keep seeing that I need three spoke routers and the switch (or fr switch enabled router) for a proper lab and just 2 spoke routers wont do it. I don't get why. Can't you set up routes with two spokes and a hub?

question 2, If I do need another router, what is a good cheap router that I can ad to the mix? Or what is a good cheap frame relay switch or router that I can replace mine with and use mine as the 3rd spoke?

question 3 My 2621 says the serial interfaces are running as DTE. I don't know why because the DCE side of the cable is plugged in to this router and previously I had ppp configured with up and up and it set itself to DCE. Is there a way to make my serial interfaces DCE? I know of the frame-relay interface-type DCE command but my 2621 wont take the command beyond frame-relay interface, for some reason it wont recognise type so I cant finish the command.

OK, alot to learn hear so I will await your responses eagerly. Thanks.

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MachX85

ok I answered one of my questions. The command frame-relay intf-type DCE wasnt working for me because I assumed intf was just abbreviating interface. Turns out this wont work unless intf is typed exactly.

frame-relay interface-type dce = bad
frame-relay intf-type dce = good

MachX85

status is now s1/1 up and up
s1/0 up and up

billscott92787

Congrats

best way to learn huh! You definitely won't forget that one anymore. I've had stuff like this happen that I'm like what the heck? Figured it out and it has stuck with me. I'm sure it will do the same with you

Agent6376

Kinda like me getting owned by setting my clock rate too high on my DCE. Gotta love the real stuff.

Neeko

In terms of hub and spoke topologies, I'm pretty sure the hub would be referring to a remote router that all spokes have VCs to, and these spokes would not have VCs between each other, hence the term 'hub and spoke'. It seems you're referring to the FR switch as the hub, which I don't believe the curriculum would be referring to.

If you just have two routers connected to the FR cloud, you can't really have a hub and spoke setup.

MachX85

hmmm, guess ill have to take a closer look at the labs topology. so If the switch is acting as a hub then do you still have to set up all the dlcis and routes on it?

Neeko

The switch is not acting as a hub, that was my point. You're thinking of it too literally. Hub in the term 'hub and spoke' does not mean a physical hub like in an Ethernet LAN, it means all spokes can access each other via one particular remote router known as the hub.

It makes no difference to the way the FR switch is set up. What is important is how VCs are set up between each remote router. If you have sites A, B and C connected to a FR network, A for exmaple may act as the hub while B and C act as spokes. B and C do not have a VC directly connecting each other, but they do have VCs to the hub, A, therefore communicate with each other via A.

MachX85

ok, so this is why you would need 3 routers in the lab besides the fr switch? because with 3 or more you can designate a hub to route for two or more VCs?

so is there anything usefull you can do with 2 routers and a FR switch or should i just get another?

thanks

Neeko

MachX85 wrote: »

ok, so this is why you would need 3 routers in the lab besides the fr switch? because with 3 or more you can designate a hub to route for two or more VCs?

so is there anything usefull you can do with 2 routers and a FR switch or should i just get another?

thanks

Basically, yes. With two routers you can still set up VCs and practive mapping, LMI commands etc. Being able to configure varying topologies allows you to experience the different network types, but I can't remember if that was even a feature on the CCNA.

Do you not have access to packet tracer or Dynamips?

MachX85

Alright thanks.

No I dont have anything like packet tracer or dynamips