> Looking for a suggestions for a good high density OC3 ATM->DS1 mux to
> connect to an NM-1A-OC3.
Do you mean a switch? There is no method to extract tributatries on an ATM
interface. The interface must run concatenated for the ATM cell mapping to
be possible. You can cross connect PVCs from T1 ATM DXI or cell based
terminations into an OC3 - but you need lots of T1 density on an ATM switch.
I beleive the LS1010 does Channelized DS3 now, but no Channelized OC3.
Maybe Lucent has this in the CBX 550, but be prepared to drop a pretty penny
for on OC3.
>
> We are an ISP selling DS1s and would like to get the best DS1
> density from
> our Ciscos, ATM muxing OC3 into DS1s looks like the best way
> to do this.
If you are trying to avoid distance costs, you should go with Frame Relay
for your customer connections. There is much less overhead and the CPE
equipment is much cheaper. Also, the traffic management is easier to
understand and articulate to customers. Try and explain why a VBR-Nrt PVC
doesn't give double the bandwidth (SCR - PCR) all the time, as can be the
case in frame relay...
The limitation is what kind of circuit you can run frame relay on. As far
as I know, OC-3 frame relay has not been Tariffed by the FCC, so you will be
capped at DS3 from the LEC. Even with DS3, using a modern Erlang-ish type
estimate, you can oversubscribe the DS3 to connect more than 28 T1 customers
(100 comes to mind). Of course, with an OC-3 ATM circuit you get more - but
is it worth the cost? In fact, depending on the location, SONET facilities
may not be available at all.
> I have looked at some vendor OC3 muxes but they are all half
> or full rack
> monsters which do everything including the kitchen sink. All
> we need is
> OC3->DS1 muxing and would like the highest DS1 density for the least
> amount of rack space.
If you would like to terminate PTP or channelized DS1s into an OC3 router
port, you will have to wait. Cisco will be shipping a 2 port CHOC3 LC for
the GSR which should allow you to extract 84 T1s from a given OC3, but I
don't know when. Amber Networks and Juniper will likeley be offering
similar products. YMMV. Finally, you will need a Special Assembly from the
LEC to get VT1.5 drops from an OC3 - a considerable process in and of
itself. If you want to do channelized service, go with CT3. If you own a
DACS - and I mean a big sucker like the Alcatel 1631, then you can play with
all sorts of channelization.
HTH,
chris
>
> -Dan
>
This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:12:28 EDT