wiki:NetworkGlossary
Last modified 6 years ago Last modified on 05/15/2013 06:19:57 AM
a.k.a. definition units notes
network characteristics
line bit rate raw bit rate bps higher than wire speed due to physical layer encoding;
we totally ignore this for all discussions
wire speed connection speed 1 Gbps for 1 Gbps NICs and switches
10 Gbps for 10 Gbps NICs and switches
bps
latency round trip time (RTT) the time is takes for a packet to travel from one end to the other and back again ms many things influence this value, including routes, number of hops, congestion from other traffic, etc.
packet loss (number of packets dropped) / (total number of packets) % many things influence this value, including routes, number of hops, congestion from other traffic, etc.
jitter packet delay variation (PDV) a concern for audio/video playback, but not for bulk data transfers
network utilization metrics
protocol overhead (number of bits in packet used for protocol headers) / (total number of bits in packet) % the only thing that influences this is which protocols are used;
For TCP with MTU 1500, this overhead is 6% (for MTU 9000, it is 1%);
for SONET, ?;
http://wiki.networksecuritytoolkit.org/nstwiki/index.php/LAN_Ethernet_Maximum_Rates,_Generation,_Capturing_%26_Monitoring#Gigabit_Ethernet_Using_TCP.2FIP
payload throughput rate of user data movement (double counts retransmitted data) bps
payload goodput rate of user data movement (does not double count retransmitted data) bps
network efficiency (payload goodput) / (wire speed) %
bandwidth bps too ambiguous to be useful if unqualified