Enrique J. Hernandez-Valencia

How will NFV/SDN transform service provider opex?

Software defined networking and network function virtualization are widely deemed two critical pillars of the future service provider network. The expectation for significant operations cost savings from network programmability, open APIs, and operations automation is frequently mentioned as one of the primary benefits of the NFV/SDN vision. Intuitively, the flexibility and simplification values attributed to NFV/SDN lead the industry to the conclusion that operating expenses will decrease. This article provides a view into the operational costs of a typical service provider and discusses how the NFV/SDN attributes can be expected to influence the business equation. The drivers of OPEX change, the directionality of the change, and the categories of OPEX most affected based on our analysis from interactions with a number of service providers worldwide are presented in a structured analysis.

Architectures for broadband residential IP services over CATV networks

The current state of the art in digital broadband access technologies to support emerging telecommunications services makes imminent the introduction of interactive broadband services-including data, video and the Internet-into the residential market. Over the last few years, much attention has been paid to the development of media access control protocols for cable TV networks that will allow the immediate support of broadband data services as the first step toward enhanced communications services for residential users. We review some of the architectural options that must be carefully considered in order to deliver Internet protocol (IP) services to such users in an efficient yet flexible manner. Future residential cable data services are expected to deliver Internet access, work-at-home applications, small business access, local area network LAN-LAN interconnect, and LAN emulation services over cable (CATV) networks.

Rate control algorithms for the ATM ABR service

Over the last couple of years both the ATM Forum and ITU-T have converged on a closed-loop, feedback based rate control mechanism as the framework for the Available Bit Rate ATM Transfer Capability. In this framework, an ABR source adapts its transmission rate to changing characteristics of the ATM network by either testing periodically the state of the network or through direct feedback from the network. The state of the network is conveyed to the source either as a simple binary feedback signaling congestion or no congestion, or as an explicit rate indicating the rate at which the source can transmit. In this paper we review the detailed framework for the ABR service standardized by the ATM Forum, the underlying service philosophy and protocol design goals for ABR flow control, and the premises and high-level performance characteristics for the more promising ABR rate control schemes proposed so far.

The building blocks of a data-aware transport network: deploying viable Ethernet and virtual wire services via multiservice ADMs

SONET/SDH technologies constitute the core transport infrastructure of major telecom service providers worldwide. As the percentage of packet-oriented traffic in the overall traffic demand continues to rise, prompted by the widespread adoption of the Internet protocol suite, and recently by the fast adoption of Ethernet services, there is increasing pressure to improve the service providers transport infrastructure in ways that make it data-aware and cost-effective for packet-oriented applications. Steps in this direction include the adoption of native physical interfaces, for Ethernet and storage area networks as service interfaces, or full integration of packet switching capabilities from Ethernet, resilient packet ring, and MPLS technologies. This article discusses the emerging building blocks for next-generation data-aware transport networks and next-generation transport network elements.

Transport delays for UMTS VoIP

We present a first-order end-to-end delay analysis of voice over IP traffic using the UMTS packet bearer service for streaming data in a MS-to-PSTN configuration scenario. Delay components are identified with and without soft handoff support.

Simple data link (SDL) protocol: an efficient and low complexity data link protocol for high-speed packet networks

The simple data link (SDL) is a framing protocol for asynchronous, variable/fixed, length packets over a general-purpose point-to-point communications channel. The SDL relies on an ATM HEC-like framing mechanism that requires no special encoding of the framed protocol data unit (PDU) such as in HDLC framing. Its low implementation complexity makes SDL particularly suitable for high-speed transmission links such as SONET/SDH point-to-point links and SONET/SDH paths, wavelength links in an optical network, and others. For a high data rate environment, SDL is a very attractive alternative to more conventional solutions such as ATM, frame relay or PPP-over-SONET (POS).

Data over transport: the generic framing procedure

Next generation optical transport networks require a light-weight traffic adaptation mechanism to multiplex low-rating electrical signals into large capacity optical channel The mechanism must be flexible, low complexity and able to support a variety of data signals operating at rates from 10 Mbps to 10 Gbps and beyond. The Generic Framing Procedure (GFP) is an ITU-T/ANSI standard specially designed to fulfill this role. This document provides an overrview of the problem, the procedures and the target applications.