Figure 12.22 below represents a point-to-point design that shows L2/L3 switching
devices connected to a transport node. In Figure 12.23 you see a comparable design
using an RPR ring. The functions of the ADM and the L2/L3 device have been consolidated
into one intelligent transport node. When you compare this design to one using
SONET/SDH with L2/L3 switching /routing the savings are significant.
Figure 12.22 shows how a configuration of L2/L3 switches requires (1) twice the
amount of fiber and (2) more optical ports to achieve the same connectivity as the ring.
This demands twice the investment in fiber and an increase in ports required to build
the metro transport network.
Figure 12.23 shows an RPR network that supports the transport functions of the traditional
ADM while simultaneously supporting the L2 traffic management and switching
functions provided by the Layer 2/3 switching equipment.
Fiber Route Savings
Notice that to connect the nodes to the L2/L3 Network in the diagram above requires
twice the amount of fiber to achieve the same connectivity as the ring. This demands
twice the investment in fiber to build the metro transport network.
Pages:
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821