3.1 upstream channel?

Hi,

VM are doing some work in my area and I lost my internet connectivity briefly today only to find now I have 5 x 3.0 upstream channels and 1 x 3.1 upstream channel.

Is this a sing of faster upload speeds on the way?

3.0 Upstream channels
Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID
1 23600000 40.770599 5120 KSym/sec 64QAM 5
2 30100000 41.020599 5120 KSym/sec 64QAM 4
3 49600000 42.270599 5120 KSym/sec 64QAM 1
4 36600000 42.020599 5120 KSym/sec 64QAM 3
5 43100000 41.770599 5120 KSym/sec 64QAM 2

3.1 Upstream channels
Channel Channel Width (MHz) Power (dBmV) FFT Type Modulation
7 10.4 37.5 2K QAM8


3.1 Upstream channels
Channel Channel Type Number of Active Subcarriers First Active Subcarrier (Hz) T3 Timeouts T4 Timeouts
7 OFDMA 208 53.4 0 0

In reply to a post by olisun:

VM are doing some work in my area and I lost my internet connectivity briefly today only to find now I have 5 x 3.0 upstream channels and 1 x 3.1 upstream channel.

Sounds good, do you have a Hub 4 then?

Yes I do.

In reply to a post by olisun:

Yes I do.

I'm on a Hub 3, and given the aging street kit, I'm not upgrading with VM, but holding out for an altnet. Keep us posted if things change

Is this likely to reduce congestion? I believe that is the weak link on VM; so with 50% more upstream channels more capacity to go around?

Has latency improved any with the 3.1 upstream?

I would assume yes but with the caveat user usage stays the same, and they dont up the speed on the packages, I expect a speed uplift is happening.

I am back on VM as of today, not sure yet if keeping it, but I have seen mild congestion creep in after 8pm Mostly visible on the upstream which cant top 40mbit now, was over 50 earlier. Downstream a little slower but single threaded not affected so streaming would be fine.

However compared to the last time i was on VM this is a considerable improvement and the level of congestion is not really interactive service affecting. Hopefully dont see it get worse. TBB graph doesnt look terrible either.

For reference I only see 4 US channels which means I probably also dont have 3.1 US channel, once they get round to my area, it should solve this US issue.

I think if they deployed 3-4 3.1 DS channels and at least 12 3.0 US channels VM would be golden everywhere.

Edited by Chrysalis (Sat 29-Oct-22 21:23:24)

Most 3.1 modems can only lock to 2 OFDM downstream blocks and no modem locks more than 8 SC-QAM 3.0 upstream channels.

The downstream OFDM blocks go from 24 to 192 MHz wide. At 14 bits per Hz 2 of those will be just fine for 2 Gbit to a single customer even without the 32 3.0 downstream QAMs the modems lock to.

3.1 upstream is way more efficient: it'll go up to 2k QAM if the plant is clean enough and can drop individual carriers if there's narrowband noise instead of the entire channel. It comes in channel sizes between 6.4 MHz, the current SC-QAM size, and 96 MHz - equivalent to 15 3.0 channels but with modulation orders way higher.

One OFDMA block upstream should be good for the foreseeable. The plan will be, in coaxial areas, to turn off the 3.0 carriers and enlarge the 3.1 block as customers move off 3.0.

There isn't enough spectrum to have 12 * 3.0 channels regardless. Would need 76.8 MHz of clean upstream which isn't there. The spectrum is flaky below 20 MHz and ends at 85. 5 or 6 SC-QAM and the 3.1 OFDMA should be fine for new speeds. Usage hasn't gone up much with folks going to Gig1 it's mostly the same stuff faster.

The RFoG areas are a different story. They can't have 3.1 upstream so will have to be packed with 3.0. 8 of them ideally.

Thank you for that explanation, so yeah once I have that 3.1 US I should be good.

Speedtesting on pfsense seems to struggle a little bit multithreaded. So will look whats going on there, is likely a pfsense or PC issue at 3.40am and on laptop it was fine with hub5 in router mode.

If you curious here is the tbb, way better than it used to be in my area.

My Broadband Ping

I spoofed the router mode mac to keep same ip.

In the old days on VM, I wouldnt get pings as stable as this either.

Pinging bbc.co.uk [151.101.64.81] with 32 bytes of data:
Reply from 151.101.64.81: bytes=32 time=13ms TTL=58
Reply from 151.101.64.81: bytes=32 time=13ms TTL=58
Reply from 151.101.64.81: bytes=32 time=13ms TTL=58
Reply from 151.101.64.81: bytes=32 time=13ms TTL=58

Ping statistics for 151.101.64.81:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 13ms, Maximum = 13ms, Average = 13ms

Edited by Chrysalis (Sun 30-Oct-22 03:48:55)

In reply to a post by Chrysalis:

Thank you for that explanation, so yeah once I have that 3.1 US I should be good.

There aren't going to be any more spectrum upgrades so what people have once the upstream channels have all been deployed and the spectrum up to 85 MHz filled are all they're getting with the ratio of 3.0 to 3.1 capacity changing.

The major forms of capacity relief will be moving customers to 3.1, heavy users offloaded to XGSPON and node splits only as a last resort.