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Thread Index [isp-clec] Re: Virtual NPA/NXX
On Saturday 31 May 2003 12:46 am, Roderick Beck wrote: > > Rod, you're confusing enterprise long distance networks with > > local-exchange (LATA) networks. Channelized DS1s carrying both voice and > > data are what companies use internally, and what CLECs might deliver on > > EELs (line side). > > No, I am not. Offer integated DS1s out of each end central office. Mux > those DS1s into DS3s at each end central office and backhaul the traffic > over dedicated interoffice DS3S to the end central office. Those DS3s hit a > mux and then are handed off to a DACS to groom the voice and data traffic > into separate trunks side interfaces. One set of trunk interfaces links to > the switch. Another set of pipes links to the Cisco routers. Okay, so you're not confusing enterprise long distance networks with local-exchange (LATA) networks. You're confusing the trunk side of the network (IMTs) with the line side of CLEC integrated-voice data networks, what CLECs might deliver on EELs (line side). The discussion that Larry started was about IMTs. > If it was IP, the DACS disappears and in fact you can do without the mux as > well. The DS3s can simply feed into the IP routers. You're positing that an IP router is simpler than a DACS. I dunno. Those PDP-11s were pretty big. Oh, you mean a modern router? Then you have to compare a modern small DACS, not the ILEC legacy boxes. I suggest looking at a Cerent or an Adtran TA4303. The latter handles 120 T1s in three rack units, with GR-303 voice concentration and DS0-level grooming. Base price is within four figures, and each T1 is IIRC around a hundred bucks. All NEBS approved DC powered CO stuff. > > Within a LATA, public network intermachine DS1s aren't channelized except > > in the end office switch -- trunks are DS1s or, if big enough, DS3s or > > SONET. > > It is not a question of whether they are channelized or not. In my example > you are backhauling DS3s of traffic that are a mix of voice and data at the > DSO level. You need to groom that traffic. You can't avoid it. You're backhauling on the line side of the CLEC network. You're also positing a collocation-heavy network, while T1 EELs are becoming more common in the real world. Larry was asking about the trunk side. > You need grooming at the CLEC POP to hand the TDM traffic off to the switch > and the IP traffic off to the aggregation router. > > So there's no ATM either. Well, in the T1-EEL world, I can suggest two good approaches. One is to stick a GR-303 DACS like the TA4303 in the CLEC POP. The other is to use ATM. Or I guess you could use IP, but whether that will pass the EEL test remains to be seen (new EEL rules are not announced yet). And it will have either inferior audio quality or lower efficiency, because eye pee headers are so fat. -- Fred Goldstein k1io fgoldstein at ionary dot com ionary Consulting http://www.ionary.com/ ------------------------ANNOUNCEMENT--------------------------------- --------------------------------------------------------------------- >> Recycle Your Hardware << Clean out your closets and make some cash. Reach thousands of ISP equipment buyers. http://www.isp-equipment.com ---------------------------------------------------------------------- ----------------------------------------------------------------------
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