US Patent 9407733 Time correction using extension fields

A method for maintaining time at a network device includes receiving a packet that (i) conforms to a protocol that does not define a dedicated field for time correction and (ii) includes a time stamp specifying a time, determining whether the received packet includes an existing field specifying time correction information to be used for correcting the time specified by the time stamp, and, in response to determining that the packet does not include an existing field specifying time correction information, adding to the packet a new field specifying time correction information to be used for correcting the time specified by the time stamp.