Metrics

DELAY:  The length of the time required to move a packet from source to destination.

LOAD: The amount of activity on a network resource.The processor use at the router or the number of

packets per second that it is currently processing Generally, the number of packets being processed per second by the router or its CPU utilization. If the load on a router becomes high, the router can advise other routers to recalculate routing tables in order to divert traffic around it.

Load Balancing: In routing the ability of a router to distribute traffic over all its network ports that are the same distance from the destination address.

Cost: Typically based on hop count. Cost values are used by routing protocols to determine the most favorable path to a particular destination. Also called path cost.

A parameter roughly proportional to the actual cost in dollars of using each network link. Some wide area network (WAN) links might have more latency but cost much less. 

MTU(Maximum Transmission Unit): Maximum packet size in bytes, that a particular interface can handle.

The largest size of packet that the router can forward without segmenting the packet into sub packets.

Reliability: The error rate of each network link.

The relative amount of anticipated downtime for a given link between two networks.

Bandwidth: The data transfer capacity, or speed of transmission, of a digital communications system as measured in bits per second.

Latency: The time interval needed to route a packet through the router or over a specific path through the internetwork. Latency can be increased by delays due to such factors as port congestion on the router, heavy router load, bandwidth utilization of links between networks, and physical distance between networks.