Routers and telecoms

binarysoul

I don't understand what telecom companies do to connect a company to the Intrenet. When I hear about a T1 line for example, I don't know the exact steps/equipment involved to make the connection possible.

So, if I have an office with 100 PC's, a couple of swtiches and a CISCO router and want a T1 line, what happens next? I assume they bring their own equipment, e.g. a DTE.

I admit I don't know this, but at least I'm trying to learn

Netstudent

The T1 will terminate at a CSU/DSU. The telco company can provide this or the comany can own their own. IF the CSU/DSU is owned by the telco, then usually their technicians will come out and mount the CSU and run the cat5 to the T1 card of your router. The telco does everything as far as setting up the line and testing.

Once your telco has established your T1, then your traffic goes to your telco's local switch. From there it probably gets routed out a OC1 or OC3 or maybe just a T3 to the internet backbone.

dtlokee

Netstudent wrote:

The T1 will terminate at a CSU/DSU. The telco company can provide this or the comany can own their own. IF the CSU/DSU is owned by the telco, then usually their technicians will come out and mount the CSU and run the cat5 to the T1 card of your router. The telco does everything as far as setting up the line and testing.

Once your telco has established your T1, then your traffic goes to your telco's local switch. From there it probably gets routed out a OC1 or OC3 or maybe just a T3 to the internet backbone.

Also it's common for the router to have a T1 WIC that has an integrated CSU/DSU so there is no need for an external one. In all of the recent T1 installs I have been involved in the telco installed a smart jack at the customer site near the Demarc point, then it was the responsability of the customer to connect the router or CSU/DSU or whatever else was required.

binarysoul

Thanks guys, that's good insight. I also found a picture that shows CSU/DSU and a typical router.

In the picture below, what is the purpose of v.35 cable? Also on the router, where usually does the other end of RJ45 connect to?

oliverw

I've seen that pic before on this forum. Really helped me understand how it all works.

The ethernet cable on the router will be going into a switch and the v.35 is your connection to the csu/dsu (i.e connects the dce to the dte).

cambei

The V.35 cable is the link to the CSU/DSU to connect to the T1 line. The ethernet connection looks to just be for the internal LAN.

georgemc

binarysoul wrote:

Thanks guys, that's good insight. I also found a picture that shows CSU/DSU and a typical router.

In the picture below, what is the purpose of v.35 cable? Also on the router, where usually does the other end of RJ45 connect to?

The other end of the RJ45 typical connects to the demarcation point between your responsibility and the telcos responsibility. As previously stated, this is typically a smartjack.