The Building Block
29
Core Block
If you have two or more switch blocks, the Cisco rule of thumb states that
you need a core block. No routing is performed at the core, only transferring
of data. It is a pass-through for the switch block, the server block, and the
Internet. Figure 1.8 shows a possible core block.
F I G U R E 1 . 8
The core block
The core is responsible for transferring data to and from the switch blocks
as quickly as possible. You can build a fast core with a frame, packet, or cell
(ATM) network technology. The Switching exam is based on an Ethernet
core network.
Typically, you would only have one subnet configured on the core net-
work. However, for redundancy and load balancing, you could have two or
more subnets configured.
Switches can trunk on a certain port or ports. This means that a port on
a switch can be a member of more than one VLAN at the same time. How-
ever, the distribution layer will handle the routing and trunking for VLANs,
Switch block A
Switch block B
Core
Core
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