CCNA RnS #16: Campus vs Data Center Network
CCNA RnS 16: Campus Network vs DC Network
In this article, I am going to talk about the two popular
network designs Campus Network and the Data Center Network (DCN)
Ethernet LAN connects user devices to the switches and switches
to other switches. This part of the LAN is called the campus network. Campus networks
provide connections to the end-users. These switches further connect to other
switches so that multiple locations can be connected.
Figure 1: Campus Network
Figure 1, above is a example of a campus network where end-users
are connected to a switch that is installed in the wiring closet. Switches that
are near to the end-users are called the Access switches. Depending on the size
of the network, there can be multiple access switches providing connectivity to
various parts of the campus network.
These access switches further connect to another switch
called the Aggregation/Distribution switch. The distribution switch is a
central point where all the access switches get connected. To simplify the large
network design the whole campus network is designed in this way. This 3 tier
design helps administrators to scale the network without disturbing the other
part of the network and isolate the problem in the network.
Coming back to the campus network, aggregation/Distribution
switches gets connected to the core switches. These core switches are the
gateway for a campus network. Gateway means anything that needs to cross the
campus network should pass through the core switch. For example, traffic from the
end-user to the application server should cross to the core switch.
Enterprises build their network to provide access to the
applications. These application servers are high compute and high throughput devices.
Sometimes they have different protocols to make communication happen between
the servers – a good example is traffic between the Database server to storage
may or may not be on Ethernet. It could be over Fiber Channels sometimes known
as Storage Area Networks (SAN). Therefore, the connectivity design for servers is
not the same as for end-users. The network setup for application server connectivity
is called the Data Center Network.
In the Data Center Network, Applications servers are
connected to Top of Rack (ToR) switches these switches are installed within the
RACK where servers are installed, and ToR is connected to other switches EoR
(End of Row) or MoR (Middle of Row) switches. As we require high throughput, we
need more processing power on switches, 10G, 40G, 100G, or more bandwidth Interfaces.
Figure 2: Data Center Network (DCN)
The Data Center network is different from the campus network
in terms of throughput, environmental conditions, and the high availability
requirement. DCN devices are installed in a controlled environment sometimes called
the server room or data center.
As you can see in Figure 2, Servers are installed in physical
racks connected to ToR switches these core switches connect to MoR or EoR
switches. The MoR and EoR switches get connected to the Data Center Network
Core SW (DCN SW). The requirement for MoR, EoR or ToR depends on the size of the network. Some network can be built without MoR or EoR.
Now as already stated the whole idea to build a network is to
do business where business applications are installed in Data Center and access
to these business applications is provided to the end users. This is the very
basic approach for an organization to adopt digitization. To allow traffic from
end-users to applications these two networks are built as mentioned in Figures
1 and 2. Finally, these networks get connected where DCN SW and Campus Core SW
are connected.
To forward traffic from an end-user to a server and vice versa, each switch performs some logic. The next one or two articles will cover switching traffic forwarding logic. Hope you find this informative!
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- CCNA RnS #12 : Ethernet Frame Type & FCS Field!
- CCNA RnS #11: Ethernet/MAC Addressing - The Network DNA
