C1-C10-alkyl 2-keto-L-gulonates are prepared by esterifying 2-keto-L-gulonic acid or diacetone-2-keto-L-gulonic acid with a C1-C10-alcohol in the presence of an acidic catalyst by a process in which the esterification is carried out in a liquid film on a hot surface with simultaneous removal of water. One embodiment provides stateful switchover of BGP sessions when one BGP host in a redundant system restarts asynchronously with respect to another host, without problems associated with bulk transfer of BGP route information. A microcontroller includes a processor, a communications module, an internal clock oscillator, a counter, and program instructions executable to cause the processor to carry out the control functions. A new driver capable of communicating with the existing network device using a common set of primitive commands is installed.