IPv6 lost and latency doubled

Overnight my connection was lost (DSL dropped), and when it came back a minute later it was without IPv6. Also on looking at the quality monitor latency has doubled.

IPv4 Quality Monitor

IPv6 Quality Monitor

Looking in the router log the connection established says:

23.03.22 03:53:51 Internet connection established successfully. IP address: 88.97.xx.xxx, DNS server: 212.23.3.100 and 212.23.6.100, gateway: 51.148.77.130, broadband PoP: BNG3.WH-MAN-RE0

23.03.22 03:53:59 Could not obtain IPv6 prefix. Reason for error: 6 (No prefixes have been assigned) [2 messages since 23.03.22 03:53:56]

23.03.22 03:54:11 Could not establish IPv6 internet connection: No response from DHCPv6 server (SOL).

Edit:

Reconnect (twice) still no IPv6 but PoP changed to BNG4.WH-MAN-RE0
Power off router for a minute still no IPv6

Edited by jelv (Wed 23-Mar-22 08:33:44)

When I called I was told my connection had been regraded a little while back - I suspect that this was the first time I had reconnected since the regrade was done.

They've just called to say they have fixed the problem and after a reconnect now I see

gateway: 51.148.77.132, broadband PoP: BNG4.THN-LON-RE0

IPv6 is working and latency seems to be back to normal.

Edited by jelv (Wed 23-Mar-22 10:14:43)

WH-MAN will be their Manchester PoP - so it looks like they moved your connection up to there rather than one of their London sites, which might explain the latency increase.

RE0 at the end is interesting, that implies a Juniper device, not sure I've seen those before at Zen, are BNG3 and BNG4 new devices? Perhaps they'd not got IPv6 setup right on the Manchester boxes?

Any account change causes a loss of the IPv6 config.
I had a GEA Migration and a separate FTTP regrade knock out the IPv6 config this week.

If they keep getting it wrong you'd think they'd learn and add checking for that to the procedure!

Moving my connection to Manchester is ridiculous. My head end exchange is Shaftesbury, Dorset - London is much closer.

If you try reconnecting, you might get a different gateway. This is a recurring complaint about Zen.

I'd tried two reconnects and a router reboot before I called Zen. Every time I was connected to a Manchester gateway with the same issues - you can see those in the IPv4 monitor in my opening post - about 7:40 x 2 and 8:20 for the reboot.

After they said they'd fixed it I reconnected and was back on a London gateway - all seems back to normal since then.

In reply to a post by SiPurdy:

Any account change causes a loss of the IPv6 config.
I had a GEA Migration and a separate FTTP regrade knock out the IPv6 config this week.

Interesting, had a GEA FTTP migration back in April 21 and a regrade back in Feb up to 300 Meg and had no issues with losing the IPv6 config.

Am on Openreach FTTP as opposed to CityFibre, which are you on?

Also I think OR connections are still terminated on their Huawei gear

tracert -4 www.thinkbroadband.com

Tracing route to www.thinkbroadband.com.cdn.cloudflare.net [104.20.171.77]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms fritz.box [192.168.8.1]
2 15 ms 3 ms 3 ms vt1.cor2.lond1.ptn.zen.net.uk [51.148.72.22]
3 4 ms 3 ms 3 ms lag-9.p2.thn-lon.zen.net.uk [51.148.73.174]
4 4 ms 3 ms 3 ms lag-1.br2.ixn-lon.zen.net.uk [51.148.73.169]
5 * 4 ms * linx-lon1.as13335.net [195.66.225.179]
6 6 ms 4 ms 4 ms 141.101.71.2
7 4 ms 3 ms 3 ms 104.20.171.77

I can't guarantee this will definitely work but if you want to switch links you need to power off your router for a couple of minutes.


Internet connection established successfully. IP address: 217.x.x.x, DNS server: 212.23.3.100 and 212.23.6.100, gateway: 51.148.72.22, broadband PoP: cor2.lond1-vt1

Edited by techguy (Thu 24-Mar-22 20:40:05)

In reply to a post by techguy:

tracert -4 www.thinkbroadband.com

Tracing route to www.thinkbroadband.com.cdn.cloudflare.net [104.20.171.77]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms fritz.box [192.168.8.1]
2 15 ms 3 ms 3 ms vt1.cor2.lond1.ptn.zen.net.uk [51.148.72.22]
3 4 ms 3 ms 3 ms lag-9.p2.thn-lon.zen.net.uk [51.148.73.174]
4 4 ms 3 ms 3 ms lag-1.br2.ixn-lon.zen.net.uk [51.148.73.169]
5 * 4 ms * linx-lon1.as13335.net [195.66.225.179]
6 6 ms 4 ms 4 ms 141.101.71.2
7 4 ms 3 ms 3 ms 104.20.171.77

Where in the uk are you? By the pings I'm guessing closer to london?

tracert -4 www.thinkbroadband.com

Tracing route to www.thinkbroadband.com.cdn.cloudflare.net [104.20.171.77]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms 192.168.1.1
2 13 ms 13 ms 13 ms vt1.cor2.lond1.ptn.zen.net.uk [51.148.72.22]
3 13 ms 14 ms 16 ms lag-9.p1.thn-lon.zen.net.uk [51.148.73.160]
4 13 ms 13 ms 13 ms lag-2.br2.thn-lon.zen.net.uk [51.148.73.155]
5 * 14 ms 16 ms linx-lon1.as13335.net [195.66.225.179]
6 27 ms 14 ms 13 ms 172.70.160.2
7 14 ms 13 ms 13 ms 104.20.171.77

Trace complete.

Dam the laws of physics!

In reply to a post by SiPurdy:

In reply to a post by techguy:

tracert -4 www.thinkbroadband.com

Tracing route to www.thinkbroadband.com.cdn.cloudflare.net [104.20.171.77]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms fritz.box [192.168.8.1]
2 15 ms 3 ms 3 ms vt1.cor2.lond1.ptn.zen.net.uk [51.148.72.22]
3 4 ms 3 ms 3 ms lag-9.p2.thn-lon.zen.net.uk [51.148.73.174]
4 4 ms 3 ms 3 ms lag-1.br2.ixn-lon.zen.net.uk [51.148.73.169]
5 * 4 ms * linx-lon1.as13335.net [195.66.225.179]
6 6 ms 4 ms 4 ms 141.101.71.2
7 4 ms 3 ms 3 ms 104.20.171.77

Where in the uk are you? By the pings I'm guessing closer to london?

tracert -4 www.thinkbroadband.com

Tracing route to www.thinkbroadband.com.cdn.cloudflare.net [104.20.171.77]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms 192.168.1.1
2 13 ms 13 ms 13 ms vt1.cor2.lond1.ptn.zen.net.uk [51.148.72.22]
3 13 ms 14 ms 16 ms lag-9.p1.thn-lon.zen.net.uk [51.148.73.160]
4 13 ms 13 ms 13 ms lag-2.br2.thn-lon.zen.net.uk [51.148.73.155]
5 * 14 ms 16 ms linx-lon1.as13335.net [195.66.225.179]
6 27 ms 14 ms 13 ms 172.70.160.2
7 14 ms 13 ms 13 ms 104.20.171.77

Trace complete.

Dam the laws of physics!

Milton Keynes , stop laughing, yes this place is as dull as the rest of the country thinks it is!

Zen are, without doubt, thr best ISP I have used, ever and have had no issues while working from home

Just added to the thread as it was mentioned that IPv6 config was lost following a regrade and someone else mentioned jelv's connection appeared to be terminating on Juniper gear.

I didn't experience either so I wonderd (purely out of interest as this stuff does interest me) wheether this was something specific to Juniper.

Speeds and latency on my own connection are just dandy.

Jelv's latency issue was down to Zen routing him to Manchester from the SW, so traffic was routed the scenic way to London via Manchester (possibly going via London within the PPP session on the way to the Manchester BNG.

For me Zen were the worst ISP I have ever been with, packet loss and latency when I joined as their on-net link from my exchange was overloaded and when I left about 12 months later the packet loss and latency were back again.

I have seen IPv6 remain when they change things, but I'd forgotten about the manual way they do it which means it can get lost with account changes.

RE0 on Jelv's trace made me think Juniper, your trace route looks more like their Plexus network i.e. Huawei.

For comparison I am on 6ms to TBB server from Sheffield on BT.

In reply to a post by Ad_G:

Jelv's latency issue was down to Zen routing him to Manchester from the SW, so traffic was routed the scenic way to London via Manchester (possibly going via London within the PPP session on the way to the Manchester BNG.

For me Zen were the worst ISP I have ever been with, packet loss and latency when I joined as their on-net link from my exchange was overloaded and when I left about 12 months later the packet loss and latency were back again.

I have seen IPv6 remain when they change things, but I'd forgotten about the manual way they do it which means it can get lost with account changes.

RE0 on Jelv's trace made me think Juniper, your trace route looks more like their Plexus network i.e. Huawei.

For comparison I am on 6ms to TBB server from Sheffield on BT.

Yeah, thay's what I thought though I'd imagine they'll have to switch over at some point what with the legislation regarding Huawei

I guess I've been lucky regarding packet loss etc, I've been told the exchange am on is one of the largest in the country and serves quite a few industrial/business estates so maybe they've overprovisioned on backhaul to allow for growth.