FTTC faster on extension / interleaved rather than on master socket / fastpath

[Xexets]

Hello,

I have BT fibre 1 FTTC in Canterbury area.
I get full speeds and very reliable connection. My modem however always shows connection 'interleaved' in download and fastpath in upload. No problem though, works great.

Yesterday, before I had to move the extension, I moved the modem to the master socket (new BT installed master socket - done in 2017). The moderm shows now fastpath connection also in download but the connection is noticeably slower (speed test shows a consistent difference of -10mbps).

It's not really a problem since I have to plug the modem on the extension anyway - but just curious why this happens? Wasn't fastpath supposed to be better than interleaved? Wasn't a master socket supposed to be better than an extension?
Thanks!

[pippincp]

If it is a master with 2 sockets (one for phone and one for internet) then you shouldn't get a connection on the extention at all for broadband. If not, you have added extra length to the supply so bound to be slower depending on length of cable to the extention.

I suspect a reporting error re fastpath/interleaving as that is controlled by DLM and wouldn't actually change immediately on changing sockets.

[Xexets]

No it’s a master with one socket. And yes that’s why I am asking because I thought that extensions would impact on speed except it does not on mine. Broadband is faster but interleaved on the extension. Fastpath but slower on master. This ever since I had the extension which was installed 3 years ago

[Checked2013]

If you briefly used the master socket it maybe the case that DLM hadn't been given long enough to adjust. If you had left it in for a week or two then you may have seen different results.

Either way, it would have been good if you had posted line stats for before and after as I'm sure you would have got the answer sooner.

[Xexets]

Thanks fair point, it was just a curiosity. I just cabled all Ethernet to go to the extension and now that everything is done and walled I got an illumination on how to get electricity close enough to the main socket to put the router there. Oh well. Interleaved on extension it is for a while now!