What is the best MTU size for BSNL FTTH connections?

[sloj]

I had a fiber break just before Holi. Today it was fixed and am surprised to see MTU has been changed to 1492. The access concentrator changed too.

 

[alap4m]

@sloj Is the Access Concentrator the same as "Service Name" in Syrotech?

 

[sloj]

No.

 

[Ajay15]

Which Brand AC they are using for you now? and previously what was it?

 

[sloj]

From the name it seems I'm connected to an AC at Kolkata, don't know the brand as they are using 00:00:5e. Previously it was an AC from my city and it was from Juniper. Internet went down for about 2 hours after midnight so I guess they are doing some changes. This could be temporary and I maybe back to my old AC again.

 

[ZeroTwo]

For Legacy BNG: 1460
For new BNG: 1492
The router automatically negotiate MTU but it never assign the negotiated MTU as per my test.

 

[sloj]

Well it depends on the router. If you are talking about the rebranded ONT/routers that is provided with FTTH connection, then there is no option to uncheck the MTU field or for auto discovery. But with own separate custom router it is possible.

 

[Chip]

The LCO set it at 1450 on my Syrotech ONT. I mean, I am not sure why. Thought it should be higher but didn't change it.

While on my Airtel and TPF connections it's set at 1492 using the MTU test method.

 

[sloj]

Best guess is they were instructed to do that and they just copy pasted the config from a file. The tech guy from my LCO did the same except 1460 on a Digisol ONT when I got the connection.

 

[Chip]

Yes, they're told by the NOC what to input. Well, since the connection is working without issues I just left it...until next time when the itch to experiment will strike me. I'll try with 1492 and work downwards