ANSI SCTE 136-2-2019 pdf free download – Cable Modem TDM Emulation Interface Standard.
5.1 Background
Throughout the evolution of communication networks the Tl and El service that is delivered to the customer hasremained relatively consistent (in large part due to the strict ITU and ANSl standards), however the method ofdelivering theT1 or El service has changed to increase efficiencies and leverage new technologies. Both SONETand ATM historically have been adapted to transport T1 and El services; now MPLS and IP networks are also beingused. Various standards bodies and vendors have created methods for circuit emulation ofTl and El services acrosslP networks,leveraging the successful ATM circuit emulation technology developed in the 90s. This standard
leverages the work done in the ITU and IETF to define circuit emulation of Tl and E1 over a DOCSIS network.This standard describes the architecture and components of a network that delivers emulated T1 orEl or NxDSoservices over DOCSIS. It defines theT1,El, or NxDS0 service delivered to the end customer, the requirements of aBSoD-TE compliant cable modem (TE-CM), and the requirements of a BSoD-TE compliant CMTS (TE-CMTS),the requirements of the TDM Emulation Adaptor (TEA), and Pscudo Wires (PW) that cross the packet networkconnecting two TEAs.
ln developing this standard, the following assumptions were made concerning the implementation and deploymentof BSOD-TE systems:
Interoperation with DOCSIS CMTS versions and options:
Existing CMTSs can lock their existing DOCSIS symbol clock or DOCSIS SYNC message generation tomaster clock inputs for both A-TDMA [RFI 2.0] and S-CDMA[PHYv3.0].The chain of clock synchronizationis that Stratum 1 Traceable Reference drives the DOCSIS master clock; the master clock drives the DOCSISdownstream timing; and the CM recovers timing from the DOCSIS downstream).
Some CM silicon originally developed for DOCSIS 1.1 or 2.0 residential data modems can be used in a designwhere the symbol clock or DOCSIs sYNC message may be recovered to generate a T1/El clock.
From time to time this document may refer to the voice communications capabilities of a TE-CM device l
TDM-IP protocol in terms of “IP Telephony.” The legalregulatory classification of lP-based voice
communications provided over cable networks and otherwise, and the legalregulatory obligations, if any, borneby providers of such voice communications, are not yet fully defined by appropriate legal and regulatory
authorities. Nothing in this standard is addressed to, or intended to affect, those issues. In particular, while thisdocument uses standard terms such as “call,” “call signaling.””telephony,” etc., it should be recalled that, whilea TE-CM device/TDM-IP protocol performs activities analogous to these PSTN functions, the manner by
which it does so differs considerably from the manner in which they are performed in the PSTN by
telecommunications carriers, and that these differences may be significant for legalregulatory purposes.Moreover, while reference is made here to “IPTelephony,” it should be recognized that this term embraces anumber of different technologies and network architectures, each with different potential associated
legal’regulatory obligations.No particular legalregulatory consequences are assumed or implied by the use ofthis term.
.TE-CMs are always connected to a TE-CMTS with QoS support for constant bit rate flows. The TE-CMTS
complies with DOCSIS 1.1 or 2.0.A DOCSIS 1.0 CMTS will not be able to host TE-CMs. DOCSIS 1.1 may belimited in upstream bandwidth; TE-CM data flows are symmetric upstream and downstream.
· Jl can be partially supported, as outline in Section 6.3.1.
.It’s not in the scope of this standard to cover interoperation between dissimilar services, i.e., between El and T1..The following requirements are market specific and are out of scope in this standard:
.Path redundancy and equipment redundancy (like redundant power supplics),Environmental hardening, such as clock stability over temperature.ANSI SCTE 136-2 pdf download.