Setting the Standards with Dr. Yaakov Stein

Welcome to our new column on standards. I hope you will find it useful and informative, and we appreciate your feedback.

Between January 16th and 27th, Study Group 13 (SG13) of the ITU-T met in the ITU headquarters in Geneva. SG13 is responsible for “next generation networks” (NGNs), and develops most of the “I,” “X,” and “Y” series of ITU Recommendations (in addition to a few Recommendations in the “F,” “G,” and “Q” series). RAD has been an active participant in SG13 meetings for several years.

 

Three new documents were “consented” upon by the Study Group plenary at this meeting, thus completing the first stage towards their publication as official ITU Recommendations. RAD’s chief scientist Yaakov Stein was editor of two of these new Recommendations (Y.1452 And Y.1453), and the third (Y.1731) is also highly significant for RAD.

 

While it was under development Y.1453 was called Y.tdmip, and it specifies methods for transporting low-rate TDM (T1, E1, T3, and E3) over UDP/IP. It is a direct extension of the published Recommendation Y.1413 for transport of TDM over MPLS networks, which was also edited by Yaakov Stein. Y.1452 describes TDMoIP as originally developed by RAD, in addition to SAToP and CESoIP.

 

Y.1452 (formerly called Y.vtoip) is entitled “Voice trunking over IP” and specifies a method for transporting multiplexed voice services over UDP/IP. Unlike standard VoIP that encapsulates individual voice segments in their own UDP/IP packets, each Y.1452 packet encapsulates multiple voice channels, thus significantly decreasing overhead per channel. The multiplexing mechanism used is AAL2, as implemented in RAD’s Vmux product line. This complements the already published Recommendation Y.1414, which describes methods for transport of voice services over MPLS networks. However, Y.1452 has another innovation, called “VoIP trunking.” Here, VoIP streams are multiplexed for transport together across IP networks, and this transport respects standard VoIP “header compression” technologies.

 

In order to achieve “Carrier Class Ethernet” service, providers need Operations, Administration, and Maintenance (OAM) functions for Ethernet. The new Recommendation Y.1731 specifies such OAM mechanisms. While under development, Y.1731 was originally called Y.ethoam, and later the name changed to Y.17ethoam to emphasize the fact that it would be published as a Y.17xx Recommendation. Unlike the Ethernet OAM developed by the IEEE “Ethernet in the First Mile” (EFM) task force, which operates at the level of a single link for access network applications, Y.1731 tackles the wider problem of ensuring the end-to-end Ethernet connectivity and service. Pre-standard features of Y.1731 have already been implemented in RAD’s ETX series of intelligent Ethernet demarcation units.