Outdated core routers cause delays

In the US and Canada, carriers suffered from slow or dropped connections on Tuesday. This could be due to outdated routers that cannot handle bgp routing tables that contain more than 512,000 entries and as a result crash or no longer accept new routings.

Internet routers are continuously provided with routings via the border gateway protocol. These routings have to guide internet traffic in the right direction. However, legacy routers cannot store more than 512,000 routes in the ternary content addressable memory, a specific memory area in routers that stores the routing table. If the routers do get more than 512K of entries, they can crash. It also happens that the devices no longer want to accept new routings or that they switch to a software mode that can cause a lot of lag.

This problem appears to have surfaced on Tuesday as the number of routings has grown to over 512,000. In the US and Canada, providers had to deal with faltering internet connections or unreachable hosting parties for several hours, ZDnet reports. For example, the LastPass site was offline for some time due to an unreachable hoster. A number of major providers have now admitted that BGP problems with older routers have played a role. The ISPs say they have taken measures to resolve the problems.

It is striking that many providers are only now deciding to intervene. In March, an ipv4 reseller already announced that there was a good chance that the 512K problem would reveal itself somewhere in August to November. Network suppliers such as Cisco have also warned their customers. However, it also seems that many companies have not replaced outdated routers or have not replaced them in time with routers that can handle the ever-growing routing tables that have to keep internet traffic afloat.