It started with ATM
Some of the old articles on communications technology that I've saved come in handy - not because there isn't more up-to-date literature, but because they remind me why, after almost thirty years in the field, I've become such a skeptic. I've seen so many promises broken. In the 1990's the communications gurus were certain that ATM was the technology that would bring about network convergence - voice and data, end-to-end, on one network infrastructure. Just for "old times' sake", and maybe for a few laughs, let's recall a few quotes from the 1990's. I must point out that these experts' statements are consistent with the opinions of many of their colleagues at the time.
The following quotes are from Dan Minoli in Network Computing October 15, 1992. Dan's bio at the time stated that he was a full-time data communications strategic planner. He is the author of many books on networking, including some very recent ones. Referring to ATM as the "latest and greatest networking technology," he states:
"ATM technology clearly will be implemented in public networks, and corporate networks will connect to these public services in much the same way they now use frame relay or X.25 services." ... "ATM will also penetrate next-generation LANs at the core as a premises technology." ... "In other words, network protocols such as TCP/IP will need to be interfaced into the ATM data-link support. A user device could be a workstation configured with an ATM card, a router configured for ATM/cell relay service or another device such as a host or a video codec." ... "Future applications will require bandwidth on both the local and wide areas that other, non-ATM solutions just can't deliver." ... "Additionally, workstation vendors and carriers have realized there are mutually beneficial advantages to using the same technology locally and over a distance instead of using different technologies, as is the case today with LANs such as Ethernet and Token-Ring connecting with WAN links such as T1 lines. In fact, this is precisely the reason that relatively expensive network bridges and routers are needed at all: They are to some extent fancy protocol and speed converters." ... "Note, however, that ATM will not necessarily eliminate the need for bridges or routers, but will diminish their primary functions in the protocol and speed conversion arena."
Mark Clarkson, who was a BYTE consulting editor when he wrote the following, was a bit more reserved in BYTE, August 1993. The article that he wrote quoted many experts in the field. Among his statements:
"Even in an industry renowned for hype and hoopla, it's difficult to comprehend the storm of hyperbole surrounding ATM. ... ATM is now being hailed as the key to interconnecting the world." ... "The truth is that the technology will do all these things, but not until all the pieces are in place." ... "Although ATM was conceived as a public telephone technology, LAN vendors and users are embracing it to such an extent that the majority of ATM products are expected to initially be used in private networks. Eventually, ATM will interconnect workstations and carry sophisticated multimedia applications, such as desktop video-conferencing." ... "Data can move from your desktop to a campus backbone, onto a private WAN and then to the public network, and back to a colleague's desktop. The same switching technology is used throughout the process." ... "ATM may be here, but as a standard it's still incomplete."
Jeff Gould was an independent networking consultant in 1994 (if it is the same Jeff Gould, he is now CEO and Director of Research at Peerstone Research) when he wrote the following conclusion in an article about ATM in Data Communications June, 1994:
"The one factor that ultimately may ensure ATM's long-term success is its ability to bridge the LAN and WAN worlds, a talent that sets ATM apart from its LAN-based rivals. Once data starts flying through the network at ultrahigh speeds, the fewer boxes and algorithms needed to sort that information out, the better."
And Now, IP/MPLS
All that was back in the 1990's, but the year 2008 has almost arrived, and the technology that is now being hailed - though definitely with less "hype and hoopla", perhaps because everyone now knows that no solution is the ultimate solution - as the infrastructure for network convergence is IP/MPLS. In April 2005, the ATM Forum, which was founded in 1991, merged with the Frame Relay Forum and the MPLS Forum to form the MFA (MPLS-Frame Relay-ATM) Forum. The new forum was organized "with the intent of converging the implementation of multi service packet technologies in the global networking communications industry," according to Andrew Malis, President and Chairman of the Board of the MFA Forum. However, it was decided that the name does not reflect their present focus and the forum was renamed the IP/MPLS Forum on October 22, 2007 to reflect their mission, as stated on their website, "to drive the global adoption of IP/MPLS-based technology, networks, services and solutions."
MPLS Tutorials
On the menu to the left, you can find several great tutorials on MPLS. I suggest you start with the first animation in Flash - it gives a nice overview of what MPLS is and how it works. The detailed tutorial is just that - it's got a lot of protocol detail. So, after you see the first animation, if you are interested in getting into the nitty-gritty, go on to the detailed tutorial. The third tutorial on the menu is also a Flash animation, and it will review the components and routing process.
I started out talking about ATM, an infrastructure that has certainly had its influence on the development of MPLS. In a sense, MPLS is partially an outgrowth of the fact that though ATM was conceived as an infrastructure to support voice and data, it was not imagined at the time of ATM definition that voice would be delivered over IP. The vision today is otherwise - everything over IP. The small cell size that was defined in ATM to accommodate voice - but that was never a very appropriate size for data - turned out to be called a "cell tax", not a very positive contribution to our network efficiency. However, migration to a new technology is not overnight, and ATM can still serve as an infrastructure transport for MPLS-driven networks. Much of the discussion about MPLS assumes understanding of ATM and compares the two technologies. It is therefore appropriate to include a link to our ATM portal, which includes a tutorial and a great interactive applet, in the left-hand menu. You will be able to return to this portal from the left-hand menu.
Thank you for visiting RAD University. We hope that the suggested tutorials will be helpful and we welcome your comments.
Debby Koren, "Dean" RAD University
