Cable Modem Question

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Sep 8th, 2010
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What exactly does it mean when a DOCSIS 3.0 compatible cable modem is placed in bridged node?

From my understanding, a cable modem can act like a router and do everything a typical router does, in which case you would plug your PCs directly into it and it will then allow you to access the Internet. Or it can be placed in bridged mode.

When the cable modem is acting like a router, meaning its NOT in bridged mode, it will take the LAN traffic and do a many-to-one NAT to the outside interface, and then forward the traffic know, like a Linkysys or NetGear home router does.

However, when in Bridged Mode, the cable modem basically acts as a pass through and does not do any NAT or PAT but simply allows the router connected behind it to get the ISPs public address (assuming youre using DHCP), in which case the router will assign it to its outside, in terms of client traffic, the cable modem will just act like a pass through, but it will not NAT.

IS this all correct?


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lamav Thu, 09/09/2010 - 18:57
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Joe, you're absolutely correct. In bridged mode, a cable router/modem will act as simply a modem, modulating and demodulating the RF carrier.




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