Why we need Nexus 2K ( FEX) ?

 To understand the need to Nexus 2000, we must know the Datacenter architecture designs.

There are two types of design architecture:-

1.       TOP (Top of Rack) :-

2.       EOR (End of Row ):

Each above method has its own pros n corns. Please go through the below blog to find more details about the methods.

http://netterrene.blogspot.in/2014/09/top-of-rack-vs-end-of-row.html

Below are the disadvantages of both the designs:-

TOP (Top of Rack) :-

Disadvantage:-

·         Switch management: - As each Rack requires one or two switch, the management of the switch becomes an overhead. Which requires not only extra IPs but also management tool configuration is required which has its own capability to monitor the maximum number of devices. More devices in the network, more license cost etc.

EOR (End of Row) :

  

Disadvantage:-

·         Cable requirement: - As cable runs between each server and network switch, located in different racks, increases of cable requirement and add cost to the deployment and maintenance.

·         Cable management: - More resources and skill required for cable management. It increases the overall budget of the project.

·         Time to make changes: - As more cabling infrastructure is involved, modification not only becomes tedious but also require more time.

N2K not only increases the access port for end host connection but also reduces the major disadvantages of both TOR and EOR as discussed below:-

1.       Unlike EOR, it reduces the number of cable between network and server rack as there are only few uplinks between 2k and its parent switch i.e. 5k/7k. Less cable means low cable management and procurement cost. It also in turns increases the efficiency.

2.       Cisco nexus 2000 cannot work standalone. It needs either N5k or N7k as the parent and hence it reduces the management overburden unlike TOR. Less management require less number of IP address ,network resources as well as inventory and configuration management server license.

  

Apart from the above advantages, cisco 2k has few disadvantages as well which are mentioned below:-

1.       It doesn’t perform local switching. Two servers connected to same FEX cannot communicate directly. The traffic from server-1 will go to the parent switch i.e. 5k/7K and then come back to the server-2 connected to the same Fex.