The global routing table: a new battleground for businesses

IPv6 was going to be the next big thing to happen to the world of infrastructure networks and it promised to take the world by storm. However, to this date, IPv6 adoption has been slow, despite many modern routers supporting the new standard. Whilst, ultimately, the time is running out for IPv4 based on a limited number of remaining addresses, there are still a number of issues that are preventing some businesses from a wholesale upgrade to IPv6.

According to findings by Google in January 2015, the UK’s IPv6 adoption is at 0.2 percent, whilst in Belgium the equivalent adoption rate is 31.5 percent. In the US the adoption rate, according to Google is at 13.9 percent. In mainland Europe and in the US, some of the biggest Internet Service Providers (ISPs) have adopted IPv6, where in the UK the adoption from the largest ISPs has been relatively slow.

The Routing Table Challenge

IPv6 is supported in most modern hardware, but adoption still remains relatively low. To compound the problem further, most network hardware running IPv4 traffic is quickly running out of space on the routing table.

The network plays an increasingly central role in business success as web-centric organisations host critical apps in the cloud and require consistency and reliability. However, there’s a major Internet challenge brewing that businesses may not be aware of. The exponential growth of Internet traffic is rapidly inflating the global routing table, which refers to the Internet’s total number of destination networks. Many legacy network routers, still in widespread use today, are not equipped to handle the expanding routing table, which has quadrupled in size since 2004.

This is evidenced by a major event late last year in which a series of large networks and websites suffered outages for this reason - older routers hit their default 512k routing table limit. As the global routing table continues on its rapid growth trajectory, businesses are facing increased routing instability – and major hardware upgrades – over the next few months and years.

For example, if a company is humming along with a routing table of 500,000 routes from its Internet provider, then all of a sudden a tier 1 provider adds 15,000 routes to the table, the company is pushed over the 512,000 route limit. Today, we are at about 530,000 routes in the global table, which is growing by about 1,000 a week on average.

The Cisco 6500 and 7600 router platforms are some of the most widely deployed pieces of hardware on the Internet. On the 6500/7600 platforms, the previous generation supervisor module, the “SUP2,” which reached end of life (EOL) a few years ago can only hold 512k routes total, so as that tipping point is reached, many companies are going to need emergency hardware upgrades, or they will have to take less than a full BGP table from their provider. Taking less than a full table from the upstream provider is impactful to how granular a company can control their routing, and how much insight they have into what’s going on with the full Internet table, which is definitely a step backwards.

The current generation 6500/7600 supervisor modules that are widely deployed on millions of production chassis can hold 1,024,000 routes. The default settings for memory allocation on those modules are 512k IPv4 routes and 256k IPv6 routes. While the supervisor modules can hold more than 512k IPv4 routes, a lot of companies are going to learn the hard way that they have not manually re-allocated the memory to accommodate the ever-growing routing table. You have to make a configuration change and reload the router entirely, which is painful to rollout across a global footprint, and you might not even know you need to do it.

Compounding these hardware challenges, the remaining pool of IPv4 addresses continues to shrink. To try to squeeze as much life out of what’s left, some Internet registries have started giving out smaller blocks and asking providers to route smaller allocations. However, this “de-aggregation” of IPv4 addresses also has the effect of ballooning the Internet routing table – perhaps delaying inevitable IPv6 migrations but bringing hardware upgrades to the forefront. Routing IPv6 packets is well-supported within most modern hardware, but we find customers struggling with all of the ancillary things that have to happen — retraining their NOC, rebuilding their management, monitoring, and troubleshooting tools to speak both IPv4 and IPv6, developing IPv6 operational experience and so forth. The option of “just let the routing table get a little bigger” seems like an easy fix to avoid making wholesale migrations to IPv6. Network operators will always put off large-scale technology leaps in favour of having more time to fight today’s fires, but that will not last forever.

One age-old lesson is not to fight a war on two fronts simultaneously, but this is exactly what is happening today. Organisations are facing full migrations to IPv6, which can be a costly and painstaking process, and they also need to be ready for large-scale hardware upgrades when the time comes.

IPv6 Catalysts: IoT and Cloud

In its most recent budget, the UK government announced that it would be pledging £140 million to support and develop Internet of Things (IoT) applications. This will significantly increase the number of connected network devices that need to be supported, and with the life blood of IPv4 quickly running out, it’s likely to accelerate the need for an alternative solution.

Prior to the UK budget announcement, Ofcom published a report pointing to IPv6 as the preferred infrastructure to support IoT applications, as there is a larger spectrum available and IPv6 is able to handle higher loads than its predecessor. In its report, Ofcom stated its intent to monitor the efforts of Internet Service Providers (ISPs) migrating to IPv6 to ensure that demand for IoT services can be met.

The move to IPv6 will be vital to the successful adoption of IoT. However, many ISPs and telecoms firms have been slow to make the change thus far.

With the UK government and the communications watchdog pledging their support for applications that require IPv6 to run effectively, there could be a significant uptick in the adoption of IPv6 technologies. Whilst IoT is still a relatively new area of technology, it is something that has been touted as the next big thing for the web. If there aren’t enough connections to support IoT, it’s at risk for failure.

Another major catalyst for IPv6 is the cloud. The explosion of applications, data and traditional IT services being moved to the cloud is also taking its toll on IPv4 addresses. As organisations aim to migrate or run their applications in the cloud, it’s an opportunity to simultaneously plan for IPv6 support. Most IT teams or app developers adjust or even replace their application when moving from a traditional IT environment to a cloud, where they can take advantage of things like instant provisioning, horizontal scalability or multiple geographic locations.

With IoT and cloud as two major driving factors pushing organisations toward IPv6, there is increasing regulatory backing behind the technology. Now is the time for organisations to ensure that they are prepared with IPv6 to support the growth of these applications.