[c-nsp] ISP channelized OC12 or OC3 options?

[Ziti Bake]

An ISP I assist terminates customer T1s using DS3 port
adapters.   The ISP may choose to virtually collocate
in several COs using CLEC DS3 transport.  However, it
is inconvenient to take copper DS3 hand-offs from the
CLEC.  And the DS3 port-count would be high, since
most DS3s would be half-empty.

Some options open to them are 
-use channelized OC12 or several channelized OC3s; 
...but channelized POS interfaces seem costly.
-take channelized OC12 from the CLEC, and breakout to
DS3s using 15454; use cheap DS3 PAs


I may remember how one large ISP used to terminate
T1s: frame encapsulation on the customer-loop;
connected to a Cascade frame switch at the ISP;
Cascade connected to a C7500 using DS3 frame.   Is
there a modern equivalent for terminating many T1s
cheaply?

For example, I thought I'd heard about a box that did
channelized OC3 in from end-loops, and ethernet out to
the ISP.  It would be interesting if such a box could
map each T1 channel from the OC3 onto a separate VLAN
on the ethernet side; or forward each T1 as an L2TP or
PPPoE connection to a BRAS.  That would let the ISP
terminate layer-3 on a Cisco with Vlan or
Virtual-Access interfaces, without buying $40k
line-cards.

Other suggestions? 


	
		
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