Switching

Hello,

Please can any one explain to me what is the main difference between these :

EX4600-40F-AFI-T

EX4600-40F-AFO

EX4600-40F-AFI

I just  checked the datasheet but didn't get it well ..

I think front to back and back to front is one reason but , How to choose the suitable ?

AFO and AFI refer to the direction of the airflow.

So, it will mean whether you want front-to-back or back-to-front cooling

Just found this article which explains AFO and AFI in a more practical sense

https://www.juniper.net/documentation/en_US/release-independent/junos/topics/reference/general/cooling-system-ex4550.html

Hi HDawood, 

Yes, the major difference between the models below is the Air Flow and the Power Supplies that match the air flow.

Regarding which one to choose, I would say both of them are equally good and you could choose any of them. 

• Just ensure that in data center deployments, position the switch in such a manner that the AIR IN  labels on switch components are next to the cold aisle, and AIR OUT labels on switch components are next to the hot aisle.
  EX 4600 :
• The EX 4600's have 24 SFP+ ports and 4 QSFP+ ports.
• And all the models ship with two power supplies and five fans installed by default except for EX4600-40F-S.

• The switch can be set up to work in one of two airflow directions:

  - Airflow In (AFI) –Air enters the switch through the vents in the field-replaceable units (FRUs)
  - Airflow Out (AFO) –Air enters the switch through the vents in the port panel.
• Please do not mix the Power supplies and fan modules with different airflow labels (AIR INI) and AIR OUT) or AFI and AFO in the same chassis. 
  

For more details about Fans and Power Supplies wrt EX 4600, you can refer the link: https://www.juniper.net/documentation/en_US/release-independent/junos/topics/topic-map/ex4600-cooling-system.html#jd0e217

Hope this helps. 

Please mark "Accept as solution" if this answers your query. 

Kudos are appreciated too! 

Regards, 

Sharat Ainapur

Hello HDawood,

As Luke mentioned in the previous update, AFO and AFI would mean the type of fan modules. Two variants of fan modules are available, each with a different airflow direction—back-to-front airflow, indicated by the label AIR IN (AFI), or front-to-back, indicated by the label AIR OUT (AFO). You can choose the type of module depending on your environment so as to keep the ventilation of the device proper.

https://www.juniper.net/documentation/en_US/release-independent/junos/topics/reference/general/cooling-system-ex4550.html

Hello HDawood,

please note that EX4600 is already quite old and the successor for this model is available to buy. If you need a Switch which will be in service for more years than EX4600, please check if EX4650 is the better option for you.

@HDawood and other the -T ending in any SKU generally means TAA - https://gsa.federalschedules.com/resources/taa-designated-countries/.  This is somewhat equal to "made in the USA".  This is a requirement for all Federal Government purchases, and SKUs with the -T designation are generally reserved for Fed Gov purchases.  There is an additional cost for -T SKUs, so most people outside of Fed Gov do not purchase SKUs with this designation.

BTW, an AFO or AFI SKU can be converted to opposite air flow, buy purchasing new PS and Fans of the right flow and performing a swap.  It is best, and less costly, to determine and order the right air flow day 1.

For normal connections, if the connections are from users, generally running via a patch panel, those connections generally face the cold aisle, so AFO (cold in intefaces side, air out PS side) is proper choice.  If the connections are from Servers, then the physical connection for the server itself faces the hot aisle, so that cold ait flow enters and exists server properly.  In the case the switch interface is side is just the opposite or facing hot aisle.  So in this situation you want cold air pulled in on PS side (AFI) and out interface side, matching the air flow for the servers.  This assumes servers and switches are in the same cabinet, which is often the case.

Thanks all for your reply ..

If I have the secnario of using EX 4600 as acore and have around 20 servers directly connected on it also the uplinks from the access switches so in your opinion AFI or AFO will fit well ?

the second inquiry about the modules ( SFPs )

I need to use all the connections 10 G copper so around 30 port on EX 4600 will use DAC cable to get better performance and lest price Am i right ?

share your opnion ..

Thanks in advacne ..

HDawood,

AFI or AFO combinations all depend on the environment and position of the devices and where are they located, usually

in a rack you would have all the devices with the same airflow, most of times, within the all racks room you would have to prepare for the best airflow possible to prevent devices from over heatting.

To your first inquiry, it depends on your room and where you would prefer the switch to exhaust the hot air.

About the SFP modules, 10gig copper DAC cables should work fine and they should work as good as fiber with a lower price, if the requirements for distance fit, both optics SFP or DAC cables should provide the same performance for 10gig connections, differences increase with speed and distance.

Hope it helps.

Cheers,

Benjamin

Thanks for answering my second inquiry ..

Regarding the first one, i explained the secnairo , what about your recommendations of the type which shall be used AFI or AFO  ?

AFI or AFO is determined by the physical setup in most data centers.  You need to check with your physical location that will rack the ex4600 to see if they run the hot / cold aisle system.

You will then be told if your front of rack is in the hot or the cold aisle for the plan.  

In cold back you want AFI

In hot back you want AFO

https://www.energystar.gov/products/low_carbon_it_campaign/12_ways_save_energy_data_center/hot_aisle_cold_aisle_layout

Does EX4600 come with a two power supplies ?

in other words if i'm going to use it with another EX4600 in a VC shall I  purchase another power supply to avoid failure in the power source ?

or it is enough the power it has ?

Hi HDawood, 

1]   Yes,  the EX4600 is shipped from the factory with two power supplies.

Each power supply is a hot-removable and hot-insertable field-replaceable unit (FRU) when the second power supply is installed and running.

2]  If you are going to purchase another EX 4600 to setup Virtual Chassis, that too will be shipped with 2 Power Supplies. I believe you can purchase another power supply a spare, also note that if you have a valid support contract then you could get a replacement for the failed power supply. 

For more details wrt EX 4600 Power Supply, refer : https://www.juniper.net/documentation/en_US/release-independent/junos/topics/topic-map/ex4600-power-system.html

Hope this helps. 

Please mark "Accept as solution" if this answers your query. 

Kudos are appreciated too! 

Regards, 

Sharat Ainapur

Thanks All for being here to help ..