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jimk
Premium
join:2006-04-15
Raleigh, NC
Reviews:
·Time Warner Cable
·voip.ms

1 edit
reply to cramer

Re: [TWC] Raleigh, NC TWC - which modem is best to purchase?

said by cramer:

...apparently due to a problem renewing the cable modem's management IP address via DHCP.

This is most likely the same issue that's been around for ~2 YEARS where nothing can *renew* a lease -- the 10/8 private address that answers the broadcast dhcp discovery, won't answer unicast dhcp requests. (initial configuration is done entirely by broadcast, as the thing seeking an address doesn't have one. renewal is done via unicast.[see also])

Thank you for providing this information.

This is very interesting. I'm familiar with how DHCP works and have debugged it before. I have been thinking that if I could just see the traffic between the cable modem and DHCP server that it would be real easy to get to the bottom of this.

This explanation does make sense. There aren't widespread complaints about this issue on this modem... I saw one on the Suddenlink forum, and that's about it... so it makes more sense for it to be a cable provider network issue than a modem issue. Tons of people have this modem on Comcast and don't seem to be complaining about this.

One interesting thing is that I haven't noticed this issue with other cable modems, but they may simply be reacting to the situation differently.

cramer
Premium
join:2007-04-10
Raleigh, NC
kudos:8

I've watched the traffic between me and the network -- only they can see what's going on from the modem on. The problem is a) they aren't looking, and b) there aren't thousands of customers complaining about it. They sure as f*** should've seen this is the lab before ever deploying this setup to the field -- and yes, they do have engineering labs. I'm pretty sure it's happening to every zoom modem, but 99.9% of those people aren't noticing, and even fewer even know how to complain about it. (call the support blackhole won't get you anywhere.)

From what you've provided, it looks like the zoom rather stupidly reboots when the T2 timer expires. That's one way to re-init dhcp From what I remember from the diag data on the Arris at the office, the HFC lease is several days (over a week?) -- it was replaced by a Ubee that doesn't bounce the office off the internet 37 times a day and I have ZERO visibility into it. (business class bridged service, so outside signal stats, I have no need to get into it -- and they have every reason to not let me know shit, because I know wtf I'm complaining about... I'm a network engineer; I've been doing this longer than DOCSIS has existed.)

Our, admittedly old, pix has completely lost it's address twice now due to this crap. Rebind is a one shot with it; if it's one attempt fails, it goes back to 0.0.0.0, and if it doesn't ask for the same address, the server won't give it the same one. The much newer ASA doesn't have this problem.



jimk
Premium
join:2006-04-15
Raleigh, NC
Reviews:
·Time Warner Cable
·voip.ms

I agree that the way the Zoom modem handles this is broken (but at least it does come back online by itself). This is definitely a firmware bug since I have never seen another cable modem do this, and it is not even a sensible way to handle this problem since it should try to rebind first. It will be interesting to hear their response on this. Maybe they will issue an update for the benefit of customers who might encounter this on other providers that have broken DHCP.

I guarantee that the average customer won't notice... if they visit a web page when the modem resets and the page fails to load, they will just try again and it will work. I guarantee they aren't going to check the (hidden) event log on the modem's web page. There's not even a link to the log in the web GUI on this modem. You have to visit it manually (»192.168.100.1/RgEventLog.asp)

The same thing is true on people's PCs and routers. Not everything even provides detailed logs for DHCP, and the average user wouldn't know how to check the logs even if they were having problems. Since a properly functioning DHCP client will rebind transparently, most people would never notice this (even I didn't notice it on my pfSense box, since it works as it is supposed to).

As a side note, I agree about the annoyance of not being able to access signal stats and the event log on the Ubee (and if I recall correctly, most Motorola) modems when activated on business class. I like that the ARRIS DG860A that they have been using lately shows this information, but I have had issues with one of these modems occasionally hanging and becoming inaccessible part of the way through the startup process after it reboots itself for some reason (most likely due to an occasional T4 timeout but it hasn't happened enough to nail down a cause yet). A power cycle is required to restore service.


cramer
Premium
join:2007-04-10
Raleigh, NC
kudos:8

It will be interesting to hear their response on this. Maybe they will issue an update for the benefit of customers who might encounter this on other providers that have broken DHCP.

They as in Zoom... there's nothing they can do but physically replace the modem -- firmware is not field upgradable by the customer. (DOCSIS security requires it come from the HFC interface.) They as in TWC... they don't care... "customer owned device; it's the customer's problem" (and they know full well they are the only ones who can update its firmware.) Again, you'd think they would do a better job testing these things before putting them on the approved list.

I should dust off the Cisco IOS 12.3 bug that makes the network think the router is a modem and see what type lease they're handing out to modems -- and if it can be renewed. You'd think that wouldn't work through a modem, but it does!


jimk
Premium
join:2006-04-15
Raleigh, NC
Reviews:
·Time Warner Cable
·voip.ms

said by cramer:

They as in Zoom... there's nothing they can do but physically replace the modem -- firmware is not field upgradable by the customer. (DOCSIS security requires it come from the HFC interface.) They as in TWC... they don't care... "customer owned device; it's the customer's problem" (and they know full well they are the only ones who can update its firmware.) Again, you'd think they would do a better job testing these things before putting them on the approved list.

I'm painfully aware of the firmware situation. Comcast has pushed updates to these modems, but TWC claims they can't push firmware to customer owned modems. The truth is that they have chosen not to.

There are only a handful of supported customer owned modems, so making an effort to properly support them - including firmware updates when necessary - wouldn't be that hard.

What bothers me the most is that they keep insisting that the customer can update them. Anyone that has any knowledge of cable modems knows that's a lie. I even had one TWC technician insist that Zoom was giving me the run-around by staying that only TWC could update the firmware. I would expect this from lower tiers of support, but even tier 3 support has continued to tell these lies about how firmware updates work.

They shouldn't bother with a supported equipment list if they aren't going to properly support it with testing and firmware updates.I thought that was the whole point of buying a modem from the list vs. buying a random DOCSIS 3 modem.

Here's another thought... just thinking out loud here... what happens when there is a security vulnerability in a modem, or a bug that can negatively impact the service of other customers? I'm not saying that is the case with this particular modem, especially since it just a plain old modem. This is more likely to be a problem on the all in one modem/router/wireless gateway devices. There have been various security vulnerabilities in cable modem firmware before, and I guarantee it will happen again someday.

cramer
Premium
join:2007-04-10
Raleigh, NC
kudos:8

1 edit

TWC claims they can't push firmware to customer owned modems.

The word they're looking for is "won't". They learned their lesson screwing up everyone's SB6120 with bad firmware -- in some cases bricking them, in others making them inoperable (unable to sync.) It screwed up their modems, too... they screwed that pooch in every possible way. While I agree with the "don't f*** with customer owned hardware", when it's necessary, it has to get done; and they're the only ones who can.

Bottom line: test the firmware. only push an update to a customer device when they ask for it. They're absolved of liability at that point.

What bothers me the most is that they keep insisting that the customer can update them.

This is a simple education problem... very few understand the "physics" of the system. *I* know because I've read the standards and certification requirements. CSRs and techs don't -- and I expect they wouldn't understand them if they did.

99% of the people in the business today either weren't around in the days of modem uncapping, or have completely forgotten about it. That was the origin of the "never accept firmware from the customer side" rules.

Any RF device connected to the network that interferes with the network will have the FCC involved. It hasn't happened yet, because Cable Labs (despite all their BS) does thoroughly tests these things. We did actually learn alot from 10base2.

cramer
Premium
join:2007-04-10
Raleigh, NC
kudos:8
reply to cramer

BTW, that trick still works:

cisco# show int g0/1 | include address
Hardware is MV96340 Ethernet, address is 001b.d510.0409 (bia 001b.d510.0409)
Internet address is 10.137.20.71/19



DrDrew
That others may surf
Premium
join:2009-01-28
SoCal
kudos:15

4 edits
reply to cramer

Click for full size
Motorola release note
said by cramer:

The word they're looking for is "won't". They learned their lesson screwing up everyone's SB6120 with bad firmware -- in some cases bricking them, in others making them inoperable (unable to sync.) It screwed up their modems, too... they screwed that pooch in every possible way.

It wasn't a modem firmware update that caused the problem. It was a CMTS software update to meet updated DOCSIS 3 specs that wasn't compatible with older 6120 firmware, specifically version 1.0.1.8.

The bigger problem was Motorola was still distributing version 1.0.1.8 in it's retail modems several months after the problem came to light (1.0.1.8 was over a year old at that point, the new firmware release on retail was 1.0.3.3). The 1.0.1.8 modems wouldn't sync on CMTSs with the newer software, but the modems weren't bricked. TWC or the other cable companies couldn't update them normally since they wouldn't sync. TWC had updated the 6120 modems on their network before the CMTS update. I'd guess this is why TWC doesn't officially support new customer owned 6120s on their network, since there are still ones with 1.0.1.8 new in the box wandering around. 6121s had newer firmware from the start.

This hit all the MSOs: Charter, Comcast, Cox, BrightHouse, Optimum, and TWC all had threads about the issue here on DSLR.

If anything, TWC learned to update customer owned modem firmware more often. As far as I know TWC does update customer modem firmware, when they update other modems of the same make and model. It's can't be requested from customer support, they can't do it, most don't even know how it's done so you get a bunch of odd and wrong answers about it. Modem firmware updates are pushed by an automated process initiated/scheduled by TWCs Engineers.
--
If it's important, back it up... twice. Even 99.999% availability isn't enough sometimes.


hobgoblin
Sortof Agoblin
Premium
join:2001-11-25
Orchard Park, NY
kudos:10

"If anything, TWC learned to update customer owned modem firmware more often. As far as I know TWC does update customer modem firmware, when they update other modems of the same make and model. It's can't be requested from customer support, they can't do it, most don't even know how it's done so you get a bunch of odd and wrong answers about it. Modem firmware updates are pushed by an automated process initiated/scheduled by TWCs Engineers."

I agree totally with this paragraph.

Hob
--
"A foolish consistency is the hobgoblin of little minds."
- Ralph Waldo Emerson


herestoya

join:2013-02-10
Huntersville, NC
reply to jimk

I have the Zoom 5350 and Zoom tells me the firmware TWC should be using is 5.5.3.6 whereas I have 5.5.3.2 showing up on my stats. Does anyone from around where I am have the updated software 5.5.3.6 or is TWC not using it yet? Any help would be great.



jimk
Premium
join:2006-04-15
Raleigh, NC
Reviews:
·Time Warner Cable
·voip.ms

said by herestoya:

I have the Zoom 5350 and Zoom tells me the firmware TWC should be using is 5.5.3.6 whereas I have 5.5.3.2 showing up on my stats. Does anyone from around where I am have the updated software 5.5.3.6 or is TWC not using it yet? Any help would be great.

That's the first I have heard of that.

TWC will not update firmware on customer owned modems at this point in time. Since you cannot update the firmware you have, you are stuck with what you have at the moment.

Are you having problems with the modem?


hobgoblin
Sortof Agoblin
Premium
join:2001-11-25
Orchard Park, NY
kudos:10
reply to herestoya

said by herestoya:

I have the Zoom 5350 and Zoom tells me the firmware TWC should be using is 5.5.3.6 whereas I have 5.5.3.2 showing up on my stats. Does anyone from around where I am have the updated software 5.5.3.6 or is TWC not using it yet? Any help would be great.

Whatever Firmware needs to be used is the decision of the service provider not the modem manufacturer.

What issues do you have?

Hob
--
"A foolish consistency is the hobgoblin of little minds."
- Ralph Waldo Emerson

herestoya

join:2013-02-10
Huntersville, NC
reply to jimk

Zoom told me that TWC should be using the .6 software and they(Zoom) had no control over that, they (TWC) told me the updates are automatic and they have no control over when they are done. My problem mostly is that the internet speeds are eratic, more so than they were with my old SB4100, which is a very old modem. I was hoping for a better bump in speed and consistency. Mostly, the reaction of the Zoom rep when I told her that the firmware was 5.5.3.2, was more like uh, oh...that's old software TWC is using! And a lot of what I read elsewhere, said the Zoom 5350 was having a lot of problems with this software and the .6 software addressed this, any thoughts? So far it seems like "upgrading" my equipment was a waste of time and money!