@Kathir Yes bro. In my area, Airtel and Vi does not have 4G in two bands. They have 4G in only B1 so both of these doesnt have 4G+ in my area. I tried in Jio with B3+B5 and I am getting 4G+ but no difference in speed so I prefer using B40 in Jio which gives good speed.

1) You choose B3+B5 in Jio and see which band it connects to.
2) I guess in you case, it will connect to only one band of these.
3) Then try to connect to the band which you were unable to connect in step2 and see if you are getting signal and internet.
4) If you are able to connect to B3 and B5 separately and able to browse internet then we have to check with Jio only on which band combination they have enable 4G+ in your area.

@arunkm Thanks for your reply. I understood your scenario.

Here are my findings with Airtel.

1. When i search for Bands it lists out Band1, Band3 and Band 40 in my area.

2. I selected all the three bands. The connection is not stable. The band moves from Band40, Band3, and disconnection as well

3. Selected Band1 and Band3. Connection is stable so far. No 4G+ sign on the router. It connect with either band3 or band1

4.Selected Band1 and Band40. Router connected with Band40. No 4G+ sign.

5. I tried connecting individually on each of the band. With Band 1 download speed around 10MBps and upload around 8Mbps.

6. With band 1 and 3 combination the router connect with Band3. No 4G+ sign. The download around 8MBps and upload around 9MBps

7. With Band 3 alone the download speed around 12 Mbps and upload around 10Mbps.

Its the same case with band40 as well with any combination.

Let me post the Jio findings later.

@Kathir First you need to check the feasibility of band combination by the router. In your case, only B3+B40 is feasible by the router. B1+B3 and B1+B40 is not supported so no point in trying that. I suppose no 4G+ in your area for Airtel. Check the below link for the supported band combo by the router.

Supported band combination page

@arunkm Bro, this is the band combination they have given for the MR600 V2 version. In that B1+B3 combination exists. Only B1+B40 does not exist.

Carrier Aggregation:
B1+B3/B5/B7/B8/B20
B3+B1/B3/B5/B7/B8/B20/B28/B38/B40
B5+B1/B3/B5/B7/B40
B7+B1/B3/B5/B7/B8/B20/B28
B8+B1/B3/B7
B20+B1/B3/B7
B28+B3/B7/B40
B38+B38
B40+B40
B41+B41

The 4G+ combination exists in my area because i am getting the 4G+ symbol in two different mobiles.

@Kathir Okay. I sometime dint get 4G+ with internal antenna, I used external LPDA antenna in which i got 4G+. Sometime I got in internal antenna also. May be u have have a check at the roof. But if you are getting in your mobile then you should be getting in the router also. If not working then you may place a replacement request if it is still in the window time.

@arunkm Bro, I am also using the LPDA external antenna and all the above tests are based on external Antenna only.

In my opinion the router Firmware needs an update. In the V2 firmware the band selection is just to manually lock the bands.

I saw in one of the youtube video where in the MR600 V1 Beta firmware there is an option to select two different bands for aggregation.

Not sure in V2 they have made some software updates to have that capability or we need to wait for firmware upgrade.

I feel, there are many guys who are facing the same issue and no solution from TP-Link yet on this. I reached out to them on their support email, no response yet.

@hmit Thanks for such deep research, you save my 7k I almost did checkout.

@RahulR If your main requirement is carrier aggregation, not sure whether this MR 600 V2 really supports all the time.

So far i am unable to do the carrrier aggregation on my V2 router. In one of the other thread, one of our communitiy member posted a workaround to do the carrier aggregation and he mentioned that its working 70% of the time.

https://community.tp-link.com/en/home/forum/topic/259364?replyId=591964

You may have a look and decide.

@Sunshine  Thats all well and good for MR600 V1 but what about v2?  do we mnot get that option as I have v2 and no option as yet