I found this definition of Global Networks:

Definition of Global Networks

Currently does any Global Network exists (apart from Internet)? Can someone Quote some examples? Or non-global but on a country-wide scale(ATM network maybe)?

Doesn't every other WAN network comes under the category of "Enterprise Network"?

I want to know are there any other global networks other than the internet?

Also, I was reading about Transport layer protocol when this line caught my eye:

More than one transport layer protocol may be available to network applications. For example, the internet has two protocols - TCP and UDP. Each of these protocols provides a different set of transport layer services to in invoking applications

more specifically this line: For example, the internet has two protocols -TCP and UDP
What are some examples of non-internet Transport layer protocols?

The book briefly talked about Telephone network as WAN(Apart from the internet). But that implemented circuit-switched network. I doubt that those even had a Transport layer protocol. So, is there any other network that provides Transport-Layer services?

  • 2
    The Internet has two protocols, IPv4 and IPv6. IP stands for Internet Protocol. It is an OSI layer-3 protocol. Other transport protocols can use either version of IP and be carried on the Internet. TCP and UDP are the primary, but not the only, transport protocols in use on the Internet. In fact, you can create your own transport protocol and use it over the Internet.
    – Ron Maupin
    Dec 21, 2015 at 16:24
  • Transport layer is a term in both the TCP/IP model and the OSI model. Since the OSI model was never implemented, that only leaves TCP/IP. It doesn't make sense to talk about transport in another context, because it doesn't exist in other contexts.
    – Ron Trunk
    Dec 21, 2015 at 19:37
  • 1
    @RonMaupin Yes I am familiar with the OSI model, but my query is that are there any global network apart from Internet that may or may not use a different protocol for the transport layer
    – Jarwin
    Dec 22, 2015 at 17:36
  • @RonTrunk I am not sure I was able to comprehend completely what you said, can you please provide a reference link or say a bit more about the same?
    – Jarwin
    Dec 22, 2015 at 17:38
  • I was pointing out, in a comment, that what caught your eye which you were quoting is incorrect. It was not intended to answer your question, but to make you understand that you need be more critical of what you read. The OSI model is just a theoretical model, and the real world is often very different; there is nothing which mandates anyone or anything comply with the model. You can route traffic on the Internet which doesn't have a transport protocol, so why would any other network even need a transport protocol?
    – Ron Maupin
    Dec 22, 2015 at 17:46

2 Answers 2


There are quite a few global networks other than internet, mostly used for scientific research or military / diplomatic needs. They may or may not use IP as the needs of their users dictate.

For example, you can find the current map of the Global Lambda Integrated Facility (GLIF) here, which is one such network.

Internet2 is also a separate initiative, and while the primary Internet2 network is focused on North America, it is interconnected with similar networks in other countries.

  • Ohk, so, just to cross check, GLIF is a global network that is not implemented over IP, right? And can you shed some light on CBR ATM network service and ABR ATM network service, as in are they also implemented over internet or there is some other network?
    – Jarwin
    Dec 22, 2015 at 17:44
  • @Jarwin: No networks are implemented over IP, IP is implemented on top of a given layer-2. Certain customers may run IP on top of GLIF, but others may not - GLIF services are generally allocated at layer-1 (lambdas) or layer-2 (circuits), not at any given layer-3. Dec 23, 2015 at 18:57

Your question appears to be not, "are there any global networks other than the Internet" but "are there any global networks other than the Internet, and do any of those use a non-IP transport" and the answer here is yes. The global switched telephone network, aka the PSTN, was originally built on non-IP transports. About fifteen years ago telephone operators initiated a huge undertaking to move the PSTN from circuit-switched (TDM) to packet-switched (IP) but there are still huge chunks of the network that are non-IP.

Another example is X.25. This was a WAN technology extensively used in global networking up until the 1980s and still survives in certain niche applications today (packet radio I'm told, and some credit card/ATM uses). If you were a multinational of that time, chances are that you connected your sites in a mesh using X.25 links.

As a side note, TCP/IP is not a perfect protocol. There are some places where the cracks really start to show. Talking to satellites is one example (though there is work going in on this area, eg SCPS). I've learnt that just because protocol X is the winner in the market, doesn't mean it was technically the best...only that it was the easiest to get going and adapt. In 25 years' time we'll be running something else!

  • I really don't think the question is about IP, but about the transport-layer using something other than TCP or UDP. The OP got hold of some bad information (see the quote) that leads him to believe that only TCP and UDP are used on the Internet.
    – Ron Maupin
    Dec 20, 2016 at 16:43
  • Even the IP parts of the network are not usually the Internet. Jan 23, 2020 at 11:59

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