What is the difference between Top of Rack and End of Row?

--> When there are a lot of servers in a Data Center needs to be connected  then we use two popular network designs used in such circumstances – TOR (Top of Rack) and EOR (End of Row)

TOR ( Top Of Rack)

--> In TOR, there is one or two access switches are installed on the top of each server rack which provides network connectivity to the servers and then that access switch has the connections towards the Distribution Layer Switch which is located in the Network Rack.

--> Only a few cables going from Server Rack to the Network Rack as Servers are connected to Access Switches in Server Rack.

--> Device Count is increased in TOR as we require one or two access switches in each server rack.

--> server-to-server traffic will be Layer 2 in the Top of Rack Design.

-->  Since very less number of cable running between the server and network rack, it is quite easy to locate the cable and make changes.

--> More Rackspace and Space in the Data Center is required in TOR.

--> There may be issues with Bandwidth as all the Server traffic is going via Access Switch to Distribution.



EOR ( End Of Row)

--> In EOR, there is no access switch is installed on the top of each server rack, all the switches are placed in network rack only whereas cable from each server located in server racks runs towards the network rack.

--> Device Count is decreased in EOR as we don't require any access switches in each server rack.

--> Less Rackspace and Space in the Data Center is required in TOR.

--> if two servers in same rack and VLAN want to communicate with each other then the traffic will go to the distribution switch in network rack and then comes back which reduces the efficiency.

--> No issues with Bandwidth in EOR.

--> Modification is difficult in EOR as more number of cables are used.


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