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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: ATM (was Re: too many routes)
> Do you? When I mean voice, I mean true POTS. You present dialtone over >IP ? >(It could be done, btw), but POTS over ATM can exit right into the >DEXX's. >(DEXX = Big telco switch) Lets see you allocate an ESF B8ZS Clear >Channel T1 over IP.... Are you sure you aren't referring to a DACS or DCS here? (Digital Access and Cross-connect System). It's not quite the same as what is usually referred to as a telco switch, i.e. 5ESS et al. > CBR in a "worse case scenario" ATM net, IS TDM, not SDM. NO variance >against TAT allowed. You missed CBR (Constant Bit Rate) in your definitions. CBR is an ATM service used to do circuit emulation, i.e. deliver the same bits that a TDM T1 would deliver. >TDM = Time Division Multiplexing >SDM = Statistical Division Multiplexing. Stat muxing also known as X.25, frame relay, IP, ATM, or packet switching. In other words rather than dividing the bitstream into fixed timeslots (TDM) which guarantees that bits will arrive at the other end in a known time interval, we try to avoid sending bits with no information content and let another bitstream use the wire therefore the arrival time is not known but is a statistical probability yadda yadda. TDM is DS3's divided into 28 DS1 timeslots which can each be divided into 24 DS0 timeslots. >when running >BEYOND the SCR, I lost the extra BW, and received FECN's ...... Slowing >up the Ip. >SCR = Sustained Cell Rate Sustainable Cell Rate. This is an average rate, not a sustained flow of cells. This is something like a frame CIR in that you can burst beyond the SCR up to the Peak Cell Rate. It is used in ATM's VBR (Variable Bit Rate) service. >FECN = Forward Explicit Congestion Notification >BECN = Backwards Explicit Congestion Notification These are used in Frame Relay. ATM has no BECN but has EFCI (Explicit Forward Congestion Notification) instead of FECN. > Ahhh.. We await the completion, and proper interaction of RM, ILMI, >and OAM. Like IPv4, ATM is also evolving. Which one will win the evolutionary race? >RM = Remote Management Resource Management. Handled by special RM cells in the data stream. >ILMI = a link management interface for ATM Integrated Local Management Interface based on SNMP running through a reserved VBR VC on the network. Try to remember that there are many people on the list who are not that familiar with ATM. And given that ATM switches can't route IP packets that is probably OK. Only a few companies need to give serious thought to the IP and ATM together. ******************************************************** Michael Dillon voice: +1-650-482-2840 Senior Systems Architect fax: +1-650-482-2844 PRIORI NETWORKS, INC. http://www.priori.net "The People You Know. The People You Trust." ********************************************************
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