Xerox 6120 用户手册

SLP is a unicast and a multicast protocol. This means that messages can be 
sent to one agent at a time (unicast) or to all agents (that are listening) at the 
same time (multicast). However, a multicast is not a broadcast. In theory, 
broadcast messages are "heard" by every node on the network. Multicast 
differs from broadcast because multicast messages are only "heard" by the 
nodes on the network that have "joined the multicast group." 
For obvious reasons network routers filter almost all broadcast traffic. This 
means that broadcasts that are generated on one subnet will not be "routed" 
or forwarded to any of the other subnets connected to the router (from the 
router’s perspective, a subnet is all machines connected to one of its ports). 
Multicasts, on the other hand, are forwarded by routers. Multicast traffic from 
a given group is forwarded by routers to all subnets that have at least one 
machine that is interested in receiving the multicast for that group. 

SNMP (Simple Network Management Protocol) is a set of protocols for 
managing complex networks. SNMP works by sending messages to different 
parts of a network. SNMP-compliant devices, called agents, store data about 
themselves in Management Information Bases (MIBs) and return this data to 
the SNMP requesters.

When printing through a network, TCP/IP port number 9100 can be used to 
send raw data.

SMTP (Simple Mail Transfer Protocol) is a protocol for sending email.
This protocol was originally used to send email between servers; however, 
currently client email software uses it to send email to servers using POP.