• No shared Ethernet segments are saturated (no more than 40 percent network utilization).
• No shared Token Ring segments are saturated (no more than 70 percent network utilization).
• No WAN links are saturated (no more than 70 percent network utilization).
• The response time is generally less than 100 milliseconds.
• No segments have more than 20 percent broadcast/multicast.
• No segments have more than one cyclic redundancy check (CRC) error per million bytes of data.
• On the Ethernet segments, less than 0.1 percent of the packets result in collisions.
• On the Token Ring segments, less than 0.1 percent of the packets are soft errors that are unrelated to ring insertion.
• On the Fiber Distributed Data Interface (FDDI) segments, there has been no more than one ring operation per hour that is not related to ring insertion.
• The Cisco routers are not over-utilized (5-minute CPU utilization is no more than 75 percent).
• The number of output queue drops has not exceeded 100 in an hour on any Cisco router.
• The number of input queue drops has not exceeded 50 in an hour on any Cisco router.
• The number of buffer misses has not exceeded 25 in an hour on any Cisco router.
• The number of ignored packets has not exceeded 10 in an hour on any interface on a Cisco router.

Source: CCDA Self-Study: Designing for Cisco Internetwork Solutions (DESGN), ISBN:1-58705-141-9