DOCSIS Server is a DHCP/TFTP/TOD/syslog server that uses MySQL as a backend. If you have a DOCSIS Cable Modem headend, you can use this server to boot up cable modems and assign IP addresses to customer premise equipment. With a little bit of tweaking you could also use it as just a DHCP server attached to a MySQL database. It was designed to boot up more than 150 modems per second.
HTTP Time Protocol is a time synchronization tool that uses Web server responses (HTTP headers) instead of the NTP protocol. If you are behind a corporate firewall, NAT device, or proxy server, HTP will still be able to synchronize the time. For high precision time synchronization, use ntpd.
OmniSync is a driver for NTPd for people who are firewall-challenged. It enables systems to synchronize time when port 123 (UDP) is blocked. It allows you to sync against the daytime service, time, SNTS, IRC, ICMP, SNMP, precision time protocol (PTP -- IEEE 1588), HTTP, HTTPS (both also via proxy server), and (S)NTP via a Socks(5) proxy server. It doesn't directly set the clock, but uses NTPd for this, as this enables you to have multiple time sources as well as bad-chimer detection, etc.
SNTS (Simple Network Time Sync) is a simple, fast, and low-overhead time syncronization system for LANs. It is designed as a simple replacement for timed with better time control and better portability (for systems without a standard adjtime() call, such as Linux). It uses broadcasts to negotiate servers and set time, and allows multiple groupings of servers on a network for independent time management for groups or labs. SNTS also supports multiple servers in a single group.
chrony is a client and server for the Network Time Protocol (NTP). This program keeps your computer's clock accurate. It was specially designed to support systems with intermittent Internet connections, but it also works well in permanently connected environments. It can also use hardware reference clocks, the system real-time clock, or manual input as time references.
libmsntp is a full-featured, compact, portable SNTP library. libmsntp provides SNTP client and server functionality in a shared library with a simple API. SNTP (RFC 2030) is a simplified version of NTP, which allows precise synchronization of system clocks over a best-effort network.