Configure a Cisco 2503 Router with a Cable modem

[Guest_imported]

Ok here we go. I have a Cisco 2503 Router. This version is the one with the BRI port (For ISDN). So Now my question is How can I configure the Router to see the Cable modem as an input and then have the router be a DHCP server and send the IP addresses to each computer as they are seen. I'm pretty sure i'll use EIGRP as the Routing protocol. Also here is another question. Which port should the cable modem go into. I was thinking it would go into the AUX port. The with an Adapter for the E0 port have it going out. Is this the right assumption? I need some guidence here onthis issue. I want to get this up and running. The network will consist of a few Apple Computers and a few PCs (win 2k). Thanks for any help that anyone can provide.

 

[Guest_imported]

Ok. Sorry I forgot to add i'm using IOS 12.1
It should use DHCP. I basically need to know if this will work and what ports should I connect the devices too. I can configure everything else. I just cannot find any documentation on connecting a Cable Modem to a 2503 Router.
Please someone with knowledge about this issue let me know.

Thanks

 

[wybnormal]

No..

You have a router that is designed for a WAN configuration using the serial interface as the WAN and then the ethernet port for the LAN. The DSL modem does not count as a WAN connection per say. The output of the DSL modem is ethernet and not serial. The AUX port is really for low speed async connections like a modem. There are serial to ethernet converters but the top speed of the serial is 4Mbps and ethernet is 10Mbps (100mbps if fastethernet). Add in the 250.00 price tag and you might as well get the right router which would be a 2514 or a 1605. Both are dual ethernet routers.

Most DSL networks have no need for a routing protocol as they are point to point and your network does not exchange route information with the Telco's network.

internet---dslmodem-----2514----hub/switch----LAN

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[wybnormal]

No..

You have a router that is designed for a WAN configuration using the serial interface as the WAN and then the ethernet port for the LAN. The DSL modem does not count as a WAN connection per say. The output of the DSL modem is ethernet and not serial. The AUX port is really for low speed async connections like a modem. There are serial to ethernet converters but the top speed of the serial is 4Mbps and ethernet is 10Mbps (100mbps if fastethernet). Add in the 250.00 price tag and you might as well get the right router which would be a 2514 or a 1605. Both are dual ethernet routers.

Most DSL networks have no need for a routing protocol as they are point to point and your network does not exchange route information with the Telco's network.

internet---dslmodem-----2514----hub/switch----LAN

MikeS


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[Guest_imported]

Awesome.

So I was right. This cannot be done with this router. But First I have a Cable Modem, not DSL. Second, I already have the Serial to Ethernet Converter. Since I got this Router from a friend I figured I'd put it to use. I knew it was a WAN Router but figured I might be able to just try and use it. Since it had the 12.1 IOS. If you have differnt thoughts now that you know I have a Cable Modem and not DSL and also that I already have the adapter. I like your input. =)

Thanks

 

[Koji]

Cable modem or DSL modem - still ethernet output.

 

[wybnormal]

Koji is correct.. DSL, cable.. all the same output which is eithernet. Since you already have the converter(pretty unusual have one laying around),,, go ahead and try it. I would suggest using NAT to help isolate the LAN IPs from the WAN and the script kiddies. Use global overloading to share the 1 IP from the DSL circuit among your home net. Technically this is PAT (port address translation). If it were me, I would use the normal ethernet on the DSL side and the cobbled up ethernet on the LAN side.

internet--DSLmodem---E0|router|S0+adapter---switch/hub--LAN

I suggest the E0 facing the DSL because of the DHCP requirement. I dont know if the router can assign a DHCP address to a serial port.. it will to an ethernet port. I think the rev needed is 12.1(T) ??? someone else may remember for sure.

MikeS
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