Does plugging an RJ45 -> SFP adapter into a QSA SPF/SFP+ -> QSFP adapter work?

[Frank173]

0
I have a Mellanox SN2700 100Gb QSFP28 switch but need to plug one line of 1Gb RJ45 into the switch. I know that I can configure port speeds at the switch to 1Gb/sec. I wonder whether I can use an RJ45 -> SFP adapter and plug it into a Mellanox QSA SFP/SFP+ -> QSFP adapter?

I came across the following adapters:

https://www.amazon.com/10Gtek-Compatible-SFP-GE-T-Transceiver-1000Base-T/dp/B00U77IJ2M/ref=sr_1_11_sspa?keywords=rj45+sfp+adapter&qid=1552297670&s=gateway&sr=8-11-spons&psc=1

https://www.amazon.com/Mellanox-Network-Adapter-QSFP-MAM1Q00A-QSA/dp/B00FFVFVS0/ref=sxbs_sxwds-stvp?keywords=mellanox+qsa&pd_rd_i=B00FFVFVS0&pd_rd_r=a961c3f9-0869-42c3-9e62-1a13758d2333&pd_rd_w=37gna&pd_rd_wg=e2Bwi&pf_rd_p=5c5ea0d7-2437-4d8a-88a7-ea6f32aeac11&pf_rd_r=560ZKBPNZ57ZH2ZPJWY5&qid=1552297693&s=gateway

Would that work? Anyone with experience in this area?

 

[Frank173]

I actually found a the solution to my quest myself. I received the QSA adapter and GBIT adapter and both in combination allow for a RJ45 1Gbit connector to be plugged into a QSFP28 port on my Mellanox Switch. Here are the components I got which are confirmed to work with the Mellanox SN2700 and HPE SN2700M switches. Total Cost: Around USD 25 (I bought both adapters new on Taobao.com)

Components needed:

• 10Gtek for Cisco GLC-T/SFP-GE-T Gigabit RJ45 Copper SFP Transceiver Module, 1000Base-T
• Mellanox Network Adapter, SFP+ to QSFP (MAM1Q00A-QSA)

 

[Rand__]

Makes me wonder whether you'll need to use some kind of traffic control on that port and how it will impact the switch.
Whats the use case to have a 1G link in traffic? Or this just a secondary management access?

 

[Freebsd1976]

maybe for internet access . I have similar link for sx6012 , in my homlab ,sx6012 for high speed spark and greenplum database interconnection, but router ports are all 1G rj45 ,for internet access of server behind sx6012 ,such link is needed

 

[Frank173]

For Internet access. But as a network know-nothing, I am not sure that is the right approach. I may just connect all server machines and management ports to a 1Gb router for internet and management traffic. Though running all through the 100gb switch appears appealing to me because it will force all non internet traffic through the high bandwidth connects without having to set traffic priority. Any thoughts or recommendations?

Makes me wonder whether you'll need to use some kind of traffic control on that port and how it will impact the switch.
Whats the use case to have a 1G link in traffic? Or this just a secondary management access?

 

[Freebsd1976]

For Internet access. But as a network know-nothing, I am not sure that is the right approach. I may just connect all server machines and management ports to a 1Gb router for internet and management traffic. Though running all through the 100gb switch appears appealing to me because it will force all non internet traffic through the high bandwidth connects without having to set traffic priority. Any thoughts or recommendations?

why not only one 1G link to router and switch ? servers only link to 100G switch。

 

[Frank173]

You mean a 1G link between router and switch? Yes, that is what I am currently doing.

why not only one 1G link to router and switch ? servers only link to 100G switch。

 

[Rand__]

My setup also has 1g/10g links to a separate switch with management/internet/infra services and the high speed traffic (of participating vms) goes through the MLX switch. I do have an uplink to the regular switch too, but at 10G (for site to site traffic).