bruce@ccavax.camb.com (09/19/90)
It seems a bit silly to have everything so nicely multiplexed on enet, and then go into a router or bridge box and have to come out with a rats nest of v.35 cables to go into a T1 mux to get them all multiplexed back onto a T1 to be piped to your favorite carrier who will deliver the individual DS0s (or Nx56/64kb ckts) to remote sites. Certainly this has been the prefered way to access an IXC, but now the LECs are allowing T1s to be piped into them and broken down in their DACS for delivery to diverse locations, and moreover they are allowing direct customer control of THEIR DACs. I believe this sort of feature is available in PacTel's ADN service and I know it is available in NY Tel's NRS (Network Reconfiguration Service), and shortly to be available MA from the other NYNEX child. Whether you need to reconfigure dynamically or not, the important part here is that a T1 pipe you pack as you please gets unpacked and delivered to different places for less cost than having that many seperate DDS II ckts. Previously you only did this with the IXCs. Now you can even access an IXC via the LEC's NRS DACS, while other DS0s in the same T1 go to other IXCs and/or stay intralata. So back to our rats nest of v.35 connectors behind our LARGE cisco box. Wouldn't it be nice if cisco would take a T1 in and let us tell them that it is really 24 x 64kb, or 12 x 128kb, or 8 x 192kb, or any random mix adding up to 24 x DS0. (obviously N x 56kb also has to be catered to since LECs often insist on wasting 1/8th of the bandwidth with older equipment widely deployed). Just imagine, 24 remote 56/64kb sites with one cable from your cisco box, and NO T1/FT1 mux needed! Not possible you say! well, did anyone notice what CODEX did? They have A box for ~$5k (a bridge, not a router) that takes either of two different 3 1/2" firmware stiffies. The first flavor stiffy is <$1k, and only enables the 56/64kb port. This makes this box work for the typical end node branch office. BUT, the very same box, when loaded with the OTHER stiffy (~$5k...) becomes a nifty 24 way central site bridge. This s/w enables the T1 connector on the rear, and you simply define how many DS0s are to be combined into each ckt! If you only want 56/64kb each, you support 24 remote bridges. Note well that CODEX only changed S/W, not H/W. And maybe a 3rd (unnanounced) stiffy is labeled ISDN and does 23 remotes on the 23B + D of an ISDN PRI. If CODEX can do it, cisco certainly can too. Anyone that thinks this is a good idea should so indicate to cisco. If cisco has announced plans in this direction, my apologies for having missed them, otherwise this posting is my vote for what I expect many of us would love to see.
jh@tut.fi (Juha Heinanen) (09/19/90)
The problem of a rats nest of cables to the T1 mux can be solved by replacing the T1 mux with a Frame Relay switch. Ask when your favorite carrier can provide Frame Relay backbone service. Cisco will have Frame Relay cabability in 8.2. TDM technology is old fashioned one of the reason being the one you mentioned (ie. lack of addressability). Another reason is that fixed bandwith (the sum of which <= T1) has to be allocated for each connection. -- Juha -- -- Juha Heinanen, Tampere Univ. of Technology, Finland jh@tut.fi (Internet), tut!jh (UUCP), jh@tut (Bitnet)
chen@cunixf.cc.columbia.edu (Bill Chen) (09/21/90)
So what you're asking for is for cisco to become a T1 mux company right? I wouldn't mind, then I can get rid of my T1 muxes. Funny thing is that mux companies and carriers are moving in the opposite direction. They want to do packet switching, e.g. frame relay, 802.6. Maybe heaven's in the middle. :-) - bill _____________________________________________________________________ William Chen chen@cunixf.cc.columbia.edu Network Planning 212-854-7593 Columbia University
bruce@ccavax.camb.com (09/21/90)
In article <1990Sep20.181821.22450@cunixf.cc.columbia.edu>, chen@cunixf.cc.columbia.edu (Bill Chen) writes: > So what you're asking for is for cisco to become a T1 mux company right? > I wouldn't mind, then I can get rid of my T1 muxes. > > Funny thing is that mux companies and carriers are moving in the opposite > direction. They want to do packet switching, e.g. frame relay, 802.6. Frame relay isn't here so I can use it TODAY. It should be no huge S/W investment to give us the T1 muxing NOW, that we can use NOW. That same box, without many serial line cards, will later be used for frame relay. The box you have to use today will have TOO many serial line cards for the future. Think of it as a stepping stone, if you prefer.