Industry network leaders Cisco have recently announced a milestone of 512k has been reached in the Internet routing tables. Omar Santos an Incident manager for Cisco detailed, in a recent blog post, the previous milestone of 256k was reached back in 2008, and since then they have seen a steady growth in the size of the routing table.
Routing tables are essentially the Yellow pages of the internet, detailing how systems and services can be reached. So they serve an extremely important function. Although the growth of the tables is something that is bound to happen and has been steadily on the rise for sometime, this milestone means that equipment with a top-level maximum of 512k will now need to be replaced. This potentially means whilst the work is carried out, internet browsing speeds may visibly slow down.
The tech guys other at Cisco have been hard at work publishing work around for the older equipment thought to be effected by this upper limit. Documents have now been published for the Cisco Catalyst 6500/Cisco 7600 Series Supervisor Engine 720, Cisco ASR 9000 Series Aggregation Services Routers and Cisco ASR 1000 Series Aggregation Services Routers. The five devices listed can only handle routing tables containing 524,288 entries, and recent growth of the internet has pushed the figure well over 524,000.
Although this is a bug that is only just starting to surface, owners of equipment with upper limits of 512k are urged to upgrade as soon as possible to prevent potential further impact as the network continues to grow.
This is not the first time an upper limit on devices has been reached, in fact the ceiling was hit at both 128k and 256k marks. With vendors rushing to resolve the issues caused on both occasions.
Although the delays caused by the issues should not affect the everyday end-user, more sensitive services such as VoIP may well be impacted by the limits. ISP have witnessed and reported on internet “anomalies” which they are putting down to the limit of the routing tables in older equipment being reached.
If you would like to find out more details about the recent post, check out Cisco’s own blog post here