RBRE960 keeps dropping internet connection

[malachi1]

hi there,

after almost a year of working flawlessly, my RBRE960 started dropping internet a couple of months ago.

- the status on the orbi dashboard changes to WAITING

- the fibre modem lights continue behaving as normal

- after a few minutes, the orbi light will turn red

- unplugging/plugging in the modem cable to the orbi "fixes" the problem (no need to reboot the orbi)

the logs in Advanced -> Administration don't show anything that look related.. everything looks "normal".

sometimes i can go a few days without problems, other times it happens multiple times a day.

i've tried unplugging it for a bit, changing the cable from modem to orbi etc. there've been no changes to the setup.

[CrimpOn]

Can you please identify the Internet Service Provider (ISP)?

It would be interesting to know if this phenomenon appears to happen at specific times.

On the web interface,Advanced Tab, the blue box "Connection Status" should display information about the ISP lease:

A common lease is for 86,400 seconds (one day).  If the problem appears when the lease is due to expire, that can signal a problem with the ISP lease renewal process. Typical behavior is for the router to ask to renew the lease when 50% of the time remains, which would be when 12 hours remains. This would result in a pattern of renewals every 12 hours.  I have captured the actual DHCP conversation between my Orbi router and Spectrum (my ISP) and verified that this is exactly what happens for the IPv4 lease***.  The IPv6 lease is for one week (604,800 seconds) and the router renews the IPv6 lease at 3 1/2 days (half of one week).

***It is not trivial to capture this conversation between the router and the ISP.  If this happens sporadically, (not regularly) it may be difficult to prove to the ISP that the lease renewal is at fault.  What I did was place a managed Ethernet switch between the router and the ISP device (for Spectrum a cable modem. In your case an Optical Network Terminator (ONT))

and have the connection mirrored to one of the other ports which was connected to an Ethernet port on a computer that was monitored with Wireshark.  By displaying only the dhcp traffic, Wireshark displayed every lease renewal for both IPv4 and IPv6.  As an OCD computer nerd, this is the sort of thing that I do.  A first step would be to notice how long the original lease was and when it is scheduled to expire.  Calculating when half of the lease will remain will predict when the lease should renew for the same time.  If your ISP follows a similar pattern, then the problem would be expected to occur when the lease fully expires.  Search the Wikipedia article for reliability:

https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol 

[FURRYe38]

What Firmware version is currently loaded?
What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too?
Be sure your using a good quality LAN cable between the modem and router. CAT6A STP is recommended. 
How many RBS are deployed? 
What is the size of your home? Sq Ft?

https://kb.netgear.com/31030/What-do-the-LEDs-on-my-Orbi-mean

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@malachi1 wrote:

hi there,

after almost a year of working flawlessly, my RBRE960 started dropping internet a couple of months ago.

- the status on the orbi dashboard changes to WAITING

- the fibre modem lights continue behaving as normal

- after a few minutes, the orbi light will turn red

- unplugging/plugging in the modem cable to the orbi "fixes" the problem (no need to reboot the orbi)

the logs in Advanced -> Administration don't show anything that look related.. everything looks "normal".

sometimes i can go a few days without problems, other times it happens multiple times a day.

i've tried unplugging it for a bit, changing the cable from modem to orbi etc. there've been no changes to the setup.

---

[malachi1]

ahh interesting! thanks for that! it doesn't _seem_ to happen at specific times - sometimes during the night, sometimes during the morning.. tho it does seem have a habit of happening when i'm on a work zoom call 🙂 (but that may be a conscious bias on my part)

looking at the connection status, the lease obtained and lease expires values seem.. weird? i could be misunderstanding what they mean, but the lease obtained just stays on 5 mins, while the lease expires oscillates between 3 and 5 mins. is that... normal?

the next time it drops the connection, if i click release or renew then if the ipv4 lease is the problem, should it reconnect?

[malachi1]

thanks for replying! appreciated

current firmware: V7.2.6.21_5.0.20

i bought a new cat6 cable for the modem a few weeks ago in case that was it (the modem and base station are only a couple of feet apart), but it didn't make any difference.

the fibre modem says Chorus (they handle fibre infrastructure here in NZ) Optical Network Terminal Model Type 200.

the QR code on it links to: https://www.chorus.co.nz/q/model-type-200

satellites: i have 2 RBSE960

size of the house is around 185 m^2, so 1991-ish square feet? 2 floors.. i have the main orbi upstairs, and the 2 satellites in separate rooms a good distance from each other (and the base station). is there a way i can check if they're too close? the backhaul status for both satellites is good

orbi lights are all good, except when it drops the internet connection in which case the base station light turns red

[CrimpOn]

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@malachi1 wrote:

looking at the connection status, the lease obtained and lease expires values seem.. weird? i could be misunderstanding what they mean, but the lease obtained just stays on 5 mins, while the lease expires oscillates between 3 and 5 mins. is that... normal?

---

Legitimate value, certainly.  Normal.... I think not.  Providing a lease of 5 minutes (300 seconds) means that every customer device will renew the lease every 150 seconds.  That will generate a huge amount of activity for their DHCP servers.

There is a tradeoff with any sort of "time to live" mechanism. (Networking has many, including DNS records, for example, employ a similar mechanism:

https://ns1.com/resources/understanding-ttl-values-in-dns-records#:~:text=Time%20To%20Live%2C%20or%2... )

The tradeoff is:

• When the time to live value is very short, a change will take effect very quickly. But this can place substantial load on the servers.
• When the time to live value is very long, there is little load on the servers, but a change cannot fully take effect until every server that has cached that value gets around to updating it.

When I worked in networking, our practice was to set DHCP lease times to one day.  When a new building was coming on line and we planned to rework the network IP map, we would set the lease to a shorter time, such as five minutes.  Then, right before the change, we'd set it to 30 seconds.  Update the DHCP servers with new values.  Every device would get a new IP address in less than a minute, and we could set the time value back to a full day.

I would be tempted to call the ISP technical support line and ask, "What's up with having a DHCP lease of five minutes?  Are you getting calls from customers about their routers dropping internet?"

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@malachi1 wrote:

lease expires oscillates between 3 and 5 mins. is that... normal?

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This part totally makes sense.  Netgear is reporting the lease expiration in minutes.  It starts at 5 minutes.  After it hits 3 minutes (180 seconds), the lease should get renewed and the expiration time will go back to 5 minutes.  2 minutes and 1 minute will never be displayed because the lease renewed before the time got that short.

By my calculations, the Orbi router is renewing the IP lease 576 times every day. (as is every other customer router). Not surprising that it could fail now and again.

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@malachi1 wrote:

the next time it drops the connection, if i click release or renew then if the ipv4 lease is the problem, should it reconnect?

---

It would be interesting to try.

[FURRYe38]

I'd have the ISP check the ONT logs for any think they may find during this time frame when you've noticed the RBR is OFFLINE from the ONT and red in front. This led indication means the RBR is not getting internet services correctly from the ONT.

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@malachi1 wrote:

thanks for replying! appreciated

current firmware: V7.2.6.21_5.0.20

i bought a new cat6 cable for the modem a few weeks ago in case that was it (the modem and base station are only a couple of feet apart), but it didn't make any difference.

the fibre modem says Chorus (they handle fibre infrastructure here in NZ) Optical Network Terminal Model Type 200.

the QR code on it links to: https://www.chorus.co.nz/q/model-type-200

satellites: i have 2 RBSE960

size of the house is around 185 m^2, so 1991-ish square feet? 2 floors.. i have the main orbi upstairs, and the 2 satellites in separate rooms a good distance from each other (and the base station). is there a way i can check if they're too close? the backhaul status for both satellites is good

orbi lights are all good, except when it drops the internet connection in which case the base station light turns red

---

[CrimpOn]

Situations like this are very difficult to diagnose.  My guess is the ONT is going to say, "Everything's fine here. No problems at all." 

A couple of years ago, I used this same technique to discover that a Windows 10 laptop did not wake up correctly.  If I closed the cover (to keep the cat from walking on the keys), when I opened the cover again, there would be no internet.  The laptop was wired directly into an Orbi router How can there be NO internet???

Capturing the DHCP traffic on that Ethernet cable soon discovered a pattern:

• Laptop says, "Tell me my IP"
• Orbi says, "Offering you this IP"
• Laptop says, "Tell me my IP"
• Orbi says, "Offering you this IP"
• Laptop says....

And this went on indefinitely.  If I restarted the laptop, it worked correctly.  If I opened the Network troubleshooting wizard, it worked correctly.  The only thing that fail (every time) was opening the lid.

In this case, I would do the same thing.  After the ISP says, "Here's your IP good for 300 seconds.", I would expect to see the Orbi router say (150 seconds later), "Please renew my IP".  And then the ISP say, "Here's your IP good for 300 seconds."  Over and over, 156 times every day.

If even one time, the ISP fails to respond, the Orbi will have to abandon the IP and begin the process again. DHCP uses the connectionless UDP protocol:

https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol#Operation 

If either the DHCP request or the DHCP offer message doesn't get delivered, the whole process can fail. The renewal can have worked correctly 100's of times (maybe even 1,000's of times), but it takes only one packet collision to spoil the whole thing.

If the DHCP lease was the typical 86,400 seconds, then the Orbi has half a day to finally get a response from the ISP.  With a 300 second lease, there isn't much time to recover.

If the ISP technical support has a response, I'd love to hear what it is.  (Hint: there is a BIG sign at the front of the room where all the support staff can see it: "Tell them it's their router. They should rent one of ours."

[malachi1]

so i contacted the ISP support (orcon in NZ) and, this might come as a shock, but they weren't very helpful 🙂 as soon as i mentioned the orbi they said they don't provide support for non-orcon supplied devices..

what confused me is that when i said my query was about the 5 minute dhcp lease time i was getting, they also said "not our problem" and that that was something set on my end.. is that right?

[CrimpOn]

On the support for customer routers..... awful customer service. This must be a common question and they are just being jerks.

On the DHCP lease, that is done entirely by the ISP.  They offer an IP lease to the router which includes the length of time it is good for.

Sometimes calling back will get you a different support rep who is more knowledgeable or empathetic.

Or... ask, "Can you connect me to Level II support?  The DHCP lease is set by the ISP, not by my router."

Story.....

As one of the half-dozen people who still have a Tivo video recorder, Spectrum Cable has to provide me with a Tuning Adapter so that it can access Switched Digital Signals. (They hate this FCC rule.)  One day it started blinking and I could not get it to work.  Called Spectrum.  No good. Rolled a Spectrum technician. Support had him replace the Tuning Adapter with one of the spares on his truck.  Had him replace all the coax cable and crimp on new connectors. No good.  Went through All four Tuning Adapters on the Truck.  After a full shift at my house and talking to support at least 10 times, he gave up. "I have to go now. Sorry."

Before opening wine and looking up alternate networking companies, I called Spectrum one more time.  Nice lady said, "oh. your account is coded wrong. it says you don't have a Tuning Adapter.  Here.  Can you reset it again?"  Worked immediately.  All those hardware swaps. All that rewiring.  Worthless because some end of billing cycle process had removed the Tuning Adapter from my account.