What are we talking about?
There is a growing differentiation amonst router classes as to the roles they play within a network, beginning first with utilization and now emerging into implentation First, consider the following diagram:
Core
Routers
-------
Edge |--------------| Edge
Routers --| |--- Routers
------- / |--------------| \ -------
Customer |---------| / | | \ |---------|
Traffic ---> | | < |--------------| >| | Customer
|---------| \___| |____/ |---------| Traffic --->
/ |--------------| \
Customer |---------| / | | \ |---------|
Traffic ---> | |< |--------------| >| | Customer
|---------| \____| |____/ |---------| Traffic --->
|--------------|
^ ^
|___________________|
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