Sunday, November 19, 2017

Future = Application Layer Networking

I was having a conversation with a peer about the future of networking. The foundation of the conversation revolved around SDN and the changes that SDN brings to network operators and engineers. The point was raised to me that 'engineers and operators of future networks won't need to have the granular low level understanding of bits, bytes and protocols.' As control of the network becomes more and more software driven the engineer/operator needs only high level understanding. My response to that is: Nothing could be further from the truth! My prediction for the future is: true application layer networking. Have a predictable and deterministic path through the network based on application only.

I think in the future, of application layer routing, we will need to incorporate some level of routing intelligence on each host/end device. I'm not sure exactly what that will look like yet but, I know it is not along the lines of OSPF or EIGRP.

In our current model, for most networks (home networks and small business networks) there is a single egress point where all traffic leaves your LAN to destinations on the internet.

In mid-sized business/enterprise you'll have redundant links a backups. You may have site-to-site tunnels with IPSEC connected remote sites but anything not on your LAN or part of your remote sites still egresses a single point to destinations on the internet.

Large businesses/Enterprises may have multiple egress points to the internet, all managed by lead engineers and operators with oversight from the senior engineers, involving multiple AS's and public IPv4 subnets that span the globe. This is expensive and the bottom line is, even with all the sophistication, the workstations and end devices are still taking the shortest path out of the network based on destination IP address and not on application specific characteristics.

Routers are doing destination based forwarding all over the globe. They are not making routing decisions based on the the type of traffic in the payload of the packet.

One thing I foresee SDN doing for us is bringing dynamic intelligence into routing. Having your controller understand the link requirements of protocols and identify those protocols as they are passing through the routers and forward them based on the application traffic they are carrying not just their destination IP address.

Another thing I believe the future holds for us is true multi-path routing, where end devices, even a common smart phone, can have multiple gateways and not just redundant default gateways, instead they would be application specific gateways. For example I could be connected to my cellular network, wifi and maybe a bunch of ad-hoc networks all at the same time. Perhaps those ad-hoc networks have gateways of their own and we can use them to egress to the internet essentially giving a device like our phone, multiple egress points. Letting our devices participate in the decision making process for routing and forwarding and how to best utilize the links available to it on a per-application basis.

Sorry I went off on a minor futuristic sci-fi routing tangent for a moment.

To bring this full circle, I feel like the engineers and operators of the future will actually need to know more about the inter-workings of each protocol more than just Layer 4. If the future is anything close to application layer networking, we will actually need to be closer to the bits and bytes to understand the protocol of the applications themselves in-order to programmatically and deterministically route them to their destinations.

P.S. - I'm not talking about getting rid of IP addresses but instead introduce more to forwarding than just the destination. I'm sure all the "every packet should be treated equal" people out there are going to have a fit with this.

Comments are welcomed.

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