Technologies that Didn’t: Directory Services

23 February 2021 |

One of the most important features of the Network Operating Systems, like Banyan Vines and Novell Netware, available in the middle of the 1980’s was their integrated directory system. These directory systems allowed for the automatic discovery of many different kinds of devices attached to a network, such as printers, servers, and computers. Printers, of course, were the important item in this list, because printers have always been the bane of the network administrator’s existence. An example of one such system, an early version of Active Directory, is shown in the illustration below.

Technologies that Didn’t: ARCnet

12 January 2021 | Comments Off on Technologies that Didn’t: ARCnet

In the late 1980’s, I worked at a small value added reseller (VAR) around New York City. While we deployed a lot of thinnet (RG58 coax based Ethernet for those who don’t know what thinnet is), we also had multiple customers who used ARCnet.

Back in the early days of personal computers like the Amiga 500, the 8086 based XT (running at 4.77MHz), and the 8088 based AT, all networks were effectively wide area, used to connect PDP-11’s and similar gear between college campuses and research institutions. ARCnet was developed in 1976, and became popular in the early 1980’s, because it was, at that point, the only available local area networking solution for personal computers.

Technologies that Didn’t: Asynchronous Transfer Mode

17 November 2020 |

One of the common myths of the networking world is there were no “real” networks before the early days of packet-based networks. As myths go, this is not even a very good myth; the world had very large-scale voice and data networks long before distributed routing, before packet-based switching, and before any of the packet protocols such as IP. I participated in replacing a large scale voice and data network, including hundreds of inverse multiplexers that tied a personnel system together in the middle of the 1980’s. I also installed hundreds of terminal emulation cards in Zenith Z100 and Z150 systems in the same time frame to allow these computers to connect to mainframes and newer minicomputers on the campus.

The Hedge 54: Bob Friday and AI in Networks

30 September 2020 | Comments Off on The Hedge 54: Bob Friday and AI in Networks

AI in networks is a hotly contested subject—so we asked Bob Friday, CTO of Mist Systems, to explain the value and future of AI in networks. Bob joins Tom Ammon and Russ White for this episode.

The Hedge 51: Tim Fiola and pyNTM

9 September 2020 |

Have you ever looked at your wide area network and wondered … what would the traffic flows look like if this link or that router failed? Traffic modeling of this kind is widely available in commercial tools, which means it’s been hard to play with these kinds of tools, learn how they work, and understand how they can be effective. There is, however, an open source alternative—pyNTM. While this tool won’t replace a commercial tool, it can give you “enough to go on” for many network operators, and give you the experience and understanding needed to justify springing for a commercial product.

Technologies that Didn’t: The Fiber Distributed Data Interface

25 August 2020 | Comments Off on Technologies that Didn’t: The Fiber Distributed Data Interface

Token Ring, in its original form, was—on paper—a very capable physical transport. For instance, because of the token passing capabilities, it could make use of more than 90% of the available bandwidth. In contrast, Ethernet systems, particularly early Ethernet systems using a true “single wire” broadcast domain, cannot achieve nearly that kind of utilization—hence “every device on its own switch port.” The Fiber Distributed Data Interface, or FDDI, is like Token Ring in many ways. For instance, FDDI uses a token to determine when a station connected to the ring can transmit, enabling efficient use of bandwidth.

And yet, Ethernet is the common carrier of almost all wired networks today, and even wireless standards mimic Ethernet’s characteristics. What happened to FDDI?

Is QUIC really Quicker?

8 June 2020 | Comments Off on Is QUIC really Quicker?

QUIC is a relatively new data transport protocol developed by Google, and currently in line to become the default transport for the upcoming HTTP standard. Because of this, it behooves every network engineer to understand a little about this protocol, how it operates, and what impact it will have on the network. We did record a History of Networking episode on QUIC, if you want some background.

In a recent Communications of the ACM article, a group of researchers (Kakhi et al.) used a modified implementation of QUIC to measure its performance under different network conditions, directly comparing it to TCPs performance under the same conditions. Since the current implementations of QUIC use the same congestion control as TCP—Cubic—the only differences in performance should be code tuning in estimating the round-trip timer (RTT) for congestion control, QUIC’s ability to form a session in a single RTT, and QUIC’s ability to carry multiple streams in a single connection. The researchers asked two questions in this paper: how does QUIC interact with TCP flows on the same network, and does UIC perform better than TCP in all situations, or only some?

The Hedge 35: Peter Jones and Single Pair Ethernet

13 May 2020 | Comments Off on The Hedge 35: Peter Jones and Single Pair Ethernet

When you think of new Ethernet standards, you probably think about faster and optical. There is, however, an entire world of buildings out there with older copper cabling, particularly in the industrial realm, that could see dramatic improvements in productivity if their control and monitoring systems could be moved to IP. In these cases, what is needed is an Ethernet standard that runs over a single copper pair, and yet offers enough speed to support industrial use cases. Peter Jones joins Jeremy Filliben and Russ White to discuss single pair Ethernet.

The Hedge 28: Intent Based Networking in the IRTF

25 March 2020 | Comments Off on The Hedge 28: Intent Based Networking in the IRTF

Intent based networking is on the upslope of the hype cycle right now. In this episode of the Hedge, Alex Clemm and Jeff Tantsura join Alvaro Retana and Russ White for a discussion of Intent-Based Networking – Concepts and Definitions, a draft working its way through the Internet Research Task Force.

The Hedge 23: The MOPS Working Group

19 February 2020 | Comments Off on The Hedge 23: The MOPS Working Group

The IETF works on many things beyond IP and routing—the Media Operations (MOPS) working group is gathering input on media-related operational issues and practices, including “proposed technologies related to the deployment, engineering, and operation of media streaming and manipulation protocols and procedures in the global Internet (inter-domain) and within-domain networking.” Leslie Daigle and Eric Vyncke, the co-chairs of the MOPS working group, join Alvaro Retana and Russ White to discuss the work they are doing.