RFC 1686

Okay bestie, let's dive into RFC 1686 💖 It's titled IPng Requirements: A Cable Television Industry Viewpoint, written by M. Vecchi of Time Warner Cable 🎀 It's Category: Informational, so it's giving info rather than a standard, and it's dated August 1994 from the Network Working Group 🧚 The header doesn't list anything it obsoletes or updates, so no drama there ✨

Status of This Memo 📌

This memo gives information to the Internet community 💅 It does not specify an Internet standard of any kind 🙈 Distribution of this memo is unlimited 🦋

Abstract 📝

This doc was submitted to the IETF IPng area in response to RFC 1550 💜 Publishing it doesn't mean the IPng area accepted any of the ideas inside 🫶 The statements here are input for the technical discussions within the IETF, and they don't represent any endorsement or commitment from the cable television industry or any of its companies 🙅‍♀️ The place for comments is the big-internet@munnari.oz.au mailing list 📬

Table of Contents 📚

   1. Executive Summary ..........................................   2
   2. Cable Television Industry Overview .........................   2
   3. Engineering Considerations .................................   5
   3.1  Scaling ..................................................   5
   3.2  Timescale ................................................   5
   3.3  Transition and deployment ................................   6
   3.4  Security .................................................   7
   3.5  Configuration, administration and operation ..............   7
   3.6  Mobile hosts .............................................   8
   3.7  Flows and resource reservation ...........................   8
   3.8  Policy based routing .....................................  10
   3.9  Topological flexibility ..................................  10
   3.10 Applicability ............................................  10
   3.11 Datagram service .........................................  11
   3.12 Accounting ...............................................  11
   3.13 Support of communication media ...........................  12
   3.14 Robustness and fault tolerance ...........................  12
   3.15 Technology pull ..........................................  12
   3.16 Action items .............................................  13
   4. Security Considerations ....................................  13
   5. Conclusions ................................................  13
   6. Author's Address ...........................................  14

1. Executive Summary ✨

This paper drops comments on the IPng requirements and selection criteria, from a cable television industry viewpoint 📺 The angle is to position IPng as a potential internetworking technology for the global requirements of the future integrated broadband networks the cable industry is designing and deploying 💅 There's a section on the cable TV industry and the network architectures that support delivering entertainment programming and interactive multimedia digital services, plus telecommunication and data communication services 🎀

Cable networks reach homes, not just campuses and business parks 🏡 Broadband applications are going to reach the average, computer-shy person 🙈 Think heavy video and audio for communication, entertainment and information access 🍓 Getting these capabilities into homes means tens of millions of users 😭 The impact on the network, and the IPng requirements discussed here, include scalability, reliability and availability, support for real-time traffic, security and privacy, and operations and network management, among others 🔥

2. Cable Television Industry Overview 📡

Cable TV networks and the Internet are finding each other, and honestly it's a match made in heaven 💜 The big reason is bandwidth, the primary driver 💖 But the impact the cable TV industry has on broadband networks and services still isn't fully appreciated, which is wild 😭 This section gives a quick (and simplified) tour of cable TV networks and the trends pushing future network architectures and services ✨

The numbers are kinda iconic 📊 US cable networks pass by about 90 million homes, with roughly 56 million subscribers out of about 94 million homes total (U.S. TV CENSUS figures, 9/30/93) 🏠 There are more than 11,000 headends, and the cable TV industry has installed more than 1,000,000 network-miles 🛤️ Fiber is growing fast too, going from 13,000 miles in 1991 to 23,000 miles in 1992 🧵 In 1992 the cable industry spent an estimated $2.4 billion on construction, and $1.4 billion of that was for rebuilds and upgrades 🔧 Subscriber services brought in an estimated more than $21 billion that year, corresponding to an average subscriber rate of about $30 a month (source: Paul Kagan Associates, Inc.) 💰 These figures are for "conventional" cable TV services, and they're expected to grow as the industry moves into new interactive digital services and telecommunications 🚀

The cable industry's broadband integrated services network architecture is built as a hierarchy of network elements linked together by broadband fiber optics and coaxial cable 🧵 Here's the super simplified version 🫶 Starting at the home, a coaxial cable tree-and-branch plant gives broadband two-way access to the network 🏡 The local access coax gets aggregated at a fiber node, which is the spot where fiber optics becomes the broadband transmission medium 🌈 Right now there are approximately 500 homes passed by the coaxial cable plant for every fiber node, though it varies from as low as 100 to as many as 3000, depending on how dense the homes are and how much of the broadband services people are signing up for 📈 The links from the fiber nodes reach the headend, which is where existing cable systems have installed equipment for origination, reception and distribution of television programming 📺 Headends sit in buildings that can accommodate weather protection and power facilities, so they're the first natural spot in the network where complex switching, routing and processing equipment can be conveniently located 🏗️ Traffic from multiple headends can be routed over fiber optics to regional hub nodes deeper in the network, where capital-intensive functions can be shared in an efficient way 🤝

The cable networks are evolving super fast into effective two-way digital broadband networks 🚀 They'll continue to be asymmetric and keep delivering analog video, but digital capabilities are being installed very aggressively and a significant amount of upstream bandwidth is being activated right now 🔥 Fiber going deeper into the network is making the shared coaxial plant way more effective at carrying broadband traffic in both directions 💫 For instance, with fiber nodes down to where only about 100 to 500 homes are passed by the coaxial drops (down from tens of thousands of homes passed in the past), an upstream bandwidth of several MHz is a considerable capacity 🌸 The recent announcement by Continental Cablevision and PSI to provide Internet access services is just one example of the many things these two-way broadband capabilities can do 🌐

The cable networks are also rapidly turning into regional networks 🗺️ Fiber optic trunking facilities (many based on SONET) will provide gigabit links that interconnect regional hub nodes in regional networks spanning multiple cable systems ⚡ These gigabit networks carry digitized video programming, but they'll also carry voice (telephone) traffic and, of course, data traffic 📞 There are instances in various parts of the country where these regional networks have already run successful trials 🎉 And since compressed digital video is the way future video programs will be delivered (including interactive video, video on demand, and a whole menu of other applications like computer supported collaborative work, multiparty remote games, home shopping, customized advertisement, multimedia information services, etc.), one can be guaranteed that gigabit regional networks will be put in place at an accelerated pace 💅

The cable networks are evolving to offer broadband networking in support of a complete suite of communication services 🎬 The Orlando network being built by Time Warner is an example of a Full Service Network(TM), providing video, audio and data services to homes 💜 For the trial, ATM is brought to homes at DS3 rates, and it's expected to go up to OC-3 rates once switch interfaces are available 🛜 The Orlando trial is basically a peek into the way of future cable networks 👀 The Full Service Network uses a "set-top" box in every home to provide the network interface 📦 That "set-top" box, plus some specialized modules for video processing, is honestly a powerful computer in disguise, with computational power comparable to high-end desktop workstations 🖥️ The conventional analog cable video channels will still be available, but a significant part of the network's RF bandwidth will be devoted to digital services 📡 The network has broadband ATM switches (as well as 5E-type switches for telephony) and video servers that include all kinds of movies and information services 🍿 The important thing to notice is that the architecture of future cable networks maps directly to the way networked computing has developed 🧠 General purpose hosts (i.e., the set-top boxes) are interconnected through a broadband network to other hosts and to servers 🫶

The future broadband information superhighway is going to need architectures for both the network infrastructure and the service support environment that truly integrate the numerous applications offered to users 🛣️ Applications will cover a super wide range of scenarios 🌈 Entertainment video delivery will evolve from the cable industry's current core services into enhanced offerings like interactive video, near-video-on-demand and complete video-on-demand functions 🍿 Communication services will evolve from today's telephony and low-speed data to include interactive multimedia applications, information access services, distance learning, remote medical diagnostics and evaluations, computer supported collaborative work, multiparty remote games, electronic shopping, etc. 🩺 Beyond the complexity and diversity of the applications, the future broadband information infrastructure will combine a number of different networks that have to work together in a coherent manner 🧩 Not only will users be connected to different regional networks, but the sources of information (in the many forms they will take) will also belong to different enterprises and might be located in remote networks 🗺️ It's important to realize from the start that the two most important attributes of the architecture for the future broadband information superhighway are integration and interoperability 👑 The Internet community has important expertise and technology that could contribute to the definition and development of these future broadband networks 💖

3. Engineering Considerations ✨

okay so this section is basically the wishlist for future cable networks 🎀 the vision is one big integrated broadband network that handles interactive video, voice AND data, all together. so these are the things IPng is going to need to be able to do, bestie 💖

3.1. Scaling 🌈

okay the common wisdom is that IPng should be able to handle 10 to the 12th nodes 😭 there are around 10 to the 8th households in the US, and the estimate is about 100 times that worldwide, so roughly 10 to the 10th global households 💜 that's only about 1 percent of the 10 to the 12th nodes, which means there's still plenty of room left for business, educational, research, government, military and other nodes connected to the future Internet. so much space, it's giving abundance 🫶

BUT (and this is the part people forget 🙈) we shouldn't underestimate how many addresses each node is going to use. like, it's super likely that a single household will have more than one address for different devices 📱 think the entertainment system (interactive multimedia "next generation" television(s)), the data system (the home personal computer(s)), and other new terminal devices that will show up later, like networked games, PDAs, etc. 🎮

and the admin side matters too 💅 if there are big blocks of addresses that are assigned but never actually used, the total number of available addresses gets effectively reduced from the 10 to the 12th nodes we started with. not iconic, not cute 💀

3.2. Timescale ⭐

the cable industry is already spending big on plant upgrades 💸 and the current estimates say that by the year 1998, tens of millions of homes will be served by interactive and integrated cable networks and services. so that means trials happen during 1994, and the choices of technologies and products are well underway by 1995 ⏰ basically the critical investment and technology decisions from cable operators and their partners will be made over the next 12 to 24 months. the clock is ticking, bestie!

these time estimates are tentative, obvi, and they can shift depending on economic, technical and public policy factors 🤷‍♀️ still, the definition of the IPng capabilities and the availability of implementations should not be delayed beyond the next year, so it lines up with when all those early technology choices get made. the full development and deployment of IPng is going to be a long process that stretches past next year, of course 🌸 early implementations will let people experiment in trials, validate IPng choices, and get early buy-in from the developers of networking products that will support the planned rollout. that's the whole plan, periodt 💅

it is my opinion (the author's, not mine lol 😂) that effective support for high quality video and audio streams is one of the critical capabilities IPng needs to show off, so it can catch the attention of network operators and information providers in the interactive broadband world, like the cable television industry and its partners 📺 the currently accepted view is that IP is a great networking environment for the control side of an interactive broadband system ✅ but the challenge for IPng is proving it can also carry the broadband video and audio data streams, on top of providing networking support for the distributed control system. main character challenge fr fr 👑

3.3. Transition and deployment 🦋

the move from the current version to IPng has to think about two things: support for existing applications, and the availability of new capabilities 🧩 delivering digital video and audio programs needs broadcasting and selective multicasting that work efficiently. the interactive apps on future cable networks will be built on multimedia streams with real-time constraints, which means both the end-to-end delays and the jitter across the network have to be bounded 🎬

on top of that, these huge private investments are commercial, so the network will need better capabilities for routing choices, resource allocation, quality of service controls, security, privacy, etc. 💼 network management is also only going to get more important over time 📈 the more the current IP falls short on these needs, the bigger the push to transition, because there will be no choice but to use IPng in future applications. it's giving "adapt or get left behind" energy 💀

BUT backwards compatibility with the current IP is super important, no cap 🫶 the installed technology base built around IP can't be ignored under any reasonable evolution scenario. also, a global Internet is going to be made of lots of interconnected, heterogeneous networks, and not every subnetwork or user community will offer the full suite of interactive multimedia services 🌍 so interworking between IPng and IP has to keep going for a very, very long time 🧚

3.4. Security 🔐

the security needs of future networks fall into two big categories: protecting the users, and protecting the network resources 🛡️ the users of the future global Internet include lots of communities that will probably expect a higher level of security than what's available today: business, government, research, military, and private subscribers too. protecting users' privacy is likely to become a HOT issue as new commercial services roll out 🔥 illicitly monitoring traffic patterns by looking at the headers in IPng packets, for example, could seriously creep out most users who subscribe to new information and entertainment services 😬

network operators and information providers also expect effective protection for their resources 🏰 most of the security will probably be handled at layers above IPng, but some issues might need to be considered when defining IPng itself. one of those issues is, again, the possibility of illicitly monitoring addresses and traffic patterns through the IPng packet headers 👀 another important one is the ability to run effective network management when there are benign or malicious bugs around, especially if both source routing and resource reservation functionality are available. like, that combo needs serious thought 🙈

3.5. Configuration, administration and operation 🛠️

running these future integrated broadband networks is going to get harder, and not just because the networks themselves are bigger and more complex. the number and diversity of applications running on or through them is a big factor too 🌀 most of the issues needed for effective operations support systems belong to higher layers than IPng, but some aspects should be considered when defining IPng ✨

the area where IPng would have the MOST impact is the connected issues of resource reservation, source routing and quality of service control 💖 there's going to be tension between keeping quality high and keeping network resource usage low at the same time, especially if users can specify preferred routes through the network 🗺️ useful capabilities at the IPng level would let the network operator, or the user, monitor and direct traffic to hit quality and cost targets 💜

it's also going to matter that connectivity between endpoints, or the location of specific processes, can be dynamically reconfigured (for example, to support mobile computing terminals) 📲 the IPng design should either support this, or at least not get in the way of it 🫶 under normal conditions, resources for the new route should be established before the old route is released, so service interruption stays minimal ⚡ when reconfiguration is happening because of abnormal (i.e., failure) conditions, you'd expect longer interruptions in service, or even total loss of service 😭

the need to support heterogeneous multiple administrative domains also has big implications for which addressing schemes IPng should support 🌐 having effective ways to address nodes, processes and users is both a technical AND a business issue 💼 and the address space should be allocated and administered through fair and open processes, so choosing schemes that way is the move 💅

3.6. Mobile hosts 📱

personal and mobile communication services are already a well-established trend by now 🚀 mobile computing devices are also hitting the market at an accelerated pace 🏃‍♀️ so it would not be wise to ignore host mobility when evaluating IPng proposals. mobility will affect network addressing and routing, adaptive resource reservation, security and privacy, among other issues 🧳 not optional, bestie 🫠

3.7. Flows and resource reservation 🎀

the biggest chunk of future broadband traffic is going to come from real-time voice and video streams 📹 so the network needs to provide performance bounds for bandwidth, jitter, latency and loss, plus synchronization between media streams that are related within an application's session ⏱️ on top of that, there will be alternative network providers competing for users, offering connectivity to a choice of many available service providers 🥊 there's no question that IPng, if it wants to be a general protocol for interactive multimedia applications, will need to support some form of resource reservation or flows 🌊

two aspects are worth mentioning ✨ first, the quality of service parameters aren't known ahead of time, so the network will need flexible capabilities for defining them. for example, MPEG-II packetized video might have to be described differently than G.721 PCM packetized voice, even though both are real-time traffic channels 🎞️ in some cases soft guarantees on quality parameters might be appropriate, while in other cases hard guarantees might be required 💎 the tradeoff between cost and quality could be a really important capability of future IPng-based networks, but there's still a lot of work to be done on this 🧠 lowkey the most exciting frontier 🤩

A second big issue with resource reservations is what happens when end-to-end state gets broken or lost. 🫠 In traditional circuit-switched networks, the switching system's intelligence puts in a lot of work to detect and recover resources that were lost because they were misallocated. Future IPng networks will offer resource reservation by spreading a session's state info across several nodes in the network, so keeping that state consistent and recovering from errors in such a distributed setup is going to take real effort 💅. One idea is keep-alive messages sent to each node where a queuing policy change was made to set up the flow. That could help make sure network resources don't stay stuck in some corrupted session state 🧚. But be careful, bestie: assuming complex distributed algorithms can be made robust just by using time-outs is risky 😬. This might need innovation beyond reusing existing solutions ✨.

Recoverability is a little more chill in this networking world than in traditional distributed data processing systems 🌸. In most cases, recovering the exact session state after failures isn't needed (or even desirable). The real goal is just to make sure the system goes back to some safe state 🫶. That means no network resource stays reserved unless it was correctly assigned to a valid session. Returning to the old session state is not even meaningful, because a session's value usually disappears as time goes on 🦋. Still, administrative and management state, like usage measurement, has to follow the same conventional recoverability rules that database systems already offer 💜.

3.8. Policy based routing 🍓

In future broadband networks, there will be multiple network operators and information providers all competing for customers and traffic 👑. A big feature of IPng will be letting the source specify which specific network the traffic should follow. Users will be able to pick networks that offer performance, feature, or cost advantages 💖. From the user's side, source routing means a wider choice of network access options, which helps them get better features, performance, or cost deals ✨. From the operator and service provider side, source routing lets them offer targeted bundled services for specific users and get some degree of customer lock-in 🔒. Information providers can also optimize where their servers go and how they're distributed, whether that's point-to-point streams or multicasting to selected subgroups 🎀. Being able to dynamically specify network routing is super attractive and makes it easier to offer flexible network services 🔥.

3.9. Topological flexibility 🌈

Honestly, it's hard to predict what the future Internet's topology will look like 🙈. The current model was built to respond to a specific set of technology drivers, plus an open administrative process that reflects the sector's non-commercial nature. The future Internet will keep combining multiple administrative domains run by all kinds of network operators 🦋. We'll likely see more "gateway" nodes (at the headends or even at the fiber nodes, for example) because local and regional broadband networks will connect their users to the global Internet 🌍.

3.10. Applicability 💜

The future broadband networks being built by the cable industry and other companies are going to mix tons of different applications together 🌸. The cable industry wants to reach homes, plus schools, businesses, governments, and other campuses 🏫. The apps will focus on entertainment, remote education, telecommuting, medical stuff, community services, news delivery, and basically the whole spectrum of future information networking services 📺. Real-time video and audio streams will dominate the traffic on these broadband networks, but there's also a big chunk of non-time-critical services like messaging, file transfers, remote computing, and so on 💅. IPng's value will come from being a general internetworking technology for all of these classes of apps 👑. The future IPng market could be way wider and bigger than today's IP market, but only if the capabilities to support these diverse interactive multimedia apps actually exist ✨.

It's tough to predict how widely IPng and its related technologies will get used in future broadband networks 🤔. There will be a ton of distributed computing, both for user applications and for the network management and operation support systems that'll be needed 🖥️. This is the area where IPng could find a firm stronghold, especially since it can build on all the existing IP technology 🫶. Whether IPng can support real-time video and audio apps with the performance, quality, and cost needed to stay competitive is still an open question 😭.

3.11. Datagram service 🦋

If IPng is going to offer resource reservation or flows, the "best-effort", hop-by-hop paradigm of today's IP service will have to be reexamined 👀. The datagram paradigm could still be the basic service IPng provides for lots of apps 💖. But careful thought should go into supporting real-time traffic with (soft and/or hard) quality of service requirements 🎀.

3.12. Accounting 💸

Accounting should be a big consideration when choosing IPng 💅. Future broadband networks will be commercially motivated, so measuring how much resource each user uses will be required 🔥. Billing may or may not be based on session-by-session usage, and accounting has lots of other useful purposes beyond billing ✨. Running networks well depends on hitting availability and performance goals, both with on-the-fly actions and with long-term planning and design 🧠. Accounting info matters for both of those 🫶. That said, whether IPng should provide accounting at the IPng level should be looked at with one main goal in mind: add as little overhead as possible 🪶. Since fields for "to", "from" and time stamp will exist for any IPng choice, it's worth carefully checking what other parameters could help accounting and other network functions, so IPng stays as lean as possible 🌿.

3.13. Support of communication media 📡

The generality of IP should carry over to IPng 💖. It wouldn't be a win to design a general internetworking technology that can't run over as wide a range of communications media as possible 🙅‍♀️. It's reasonable to expect IPng to start out supported over a few select transport technologies and to rely on backwards compatibility with IP to get through a transition period 🌉. Ultimately, though, the expectation is that IPng will run over any available communications medium 🌈.

3.14. Robustness and fault tolerance 🛡️

Service availability, end-to-end and at expected performance levels, is the true measure of robustness and fault tolerance 🎯. In this sense, IPng is just one piece of a complicated puzzle 🧩. There are still some vulnerability aspects of IPng that could hurt robustness 😬. The first general class of bugs is tied to the change itself, no matter what enhancements in capabilities come with it 💀. The design, implementation, and testing process will need to be managed very carefully 🧐. Networks and distributed systems are tricky, and the Internet community has plenty of horror stories to make us cautious 😭. Then there were the brief but dramatic outages over the last couple of years, caused by relatively small software bugs in the control networks (i.e., CCS/SS7 signaling) of the telephone industry, both local and long distance 📞.

A second general class of bugs comes with implementing new capabilities 🚨. IPng will likely support a whole set of new functions, like larger (multiple?) address space(s), source routing and flows, just to name a few ✨. Providing these new capabilities will usually mean designing new distributed algorithms and testing implementation parameters super carefully 🔬. Plus, the future Internet will be even larger, have more diverse applications, and have higher bandwidth 📈. All of these factors could multiply the effect of bugs that might be easy to contain in today's network 🐛. Designers and implementers of IPng should be careful, and it will be really important to provide the best possible transition process from IP to IPng 🌸. Maintaining robustness and fault tolerance is paramount 👑.

3.15. Technology pull 🚀

The strongest "technology pull" factors shaping the Internet are the same ones speeding up the cable, telephone, and computer networking world 🏎️. Here's a partial list: higher network bandwidth, more powerful CPUs, larger and faster (static and dynamic) memory, improved signal processing and compression methods, advanced distributed computing technologies, open and extensible network operating systems, large distributed database management and directory systems, high performance and high capacity real-time servers, friendly graphical user interfaces, and efficient application development environments 🧃. These tech developments, plus the current aggressive business strategies in our industry and favorable public policies, are powerful forces that will clearly affect how IPng evolves and gets accepted 💅. The cable industry and its partners' current deployment strategies don't depend on commercial IPng capabilities existing yet 🙃. Still, new effective networking technology could become a unifying force that helps networks and services work together 🫶.

3.16. Action items 📝

Right now, we don't have any suggestions for changes to the directorate, working groups, or others to support the concerns or gather the extra info needed for a decision 🤷‍♀️. We're still available to give input to the IPng process 💌.

4. Security Considerations 🔐

No comments on general security issues are provided, beyond the considerations presented in the previous subsection 3.4 on network security 🛡️.

5. Conclusions ✨

okay so bestie, the big question here is whether IPng can be a universal internetworking solution 🌍💖 and honestly? It's a VERY attractive possibility 😭 but there are a bunch of hurdles to clear first 🫶 Like, IPng can't do it solo. It needs the whole suite of Internet technology behind it so the future networks and applications actually work 🔥 And those technologies need proper support for running a commercial global Internet, which is gonna be built, financed, and run by a ton of different private and public orgs 💅

The Internet community has been obsessed with being nimble and efficient when it comes to building and deploying network tech 🦋 And ngl, the Internet has been super successful so far 👑 But the challenge now is proving that the Internet model can be the preferred technical solution going forward 🎀 Broadband networks and services are gonna show up pretty soon, which puts the whole Internet community in a fast track race 🏁😭 The IPng process is basically a test of whether the Internet can grow from its early days (super successful, but also kinda protected and limited in scope 🌸) into a general technology that can support a commercially viable broadband marketplace 💜 If the Internet model is going to be the go-to general solution for broadband networking, then the current IPng process is a critical starting point ✨🌈

6. Author's Address 🎀

Mario P. Vecchi Time Warner Cable, 160 Inverness Drive West Englewood, CO 80112

Phone: (303) 799-5540 Fax: (303) 799-5651 EMail: mpvecchi@twcable.com