biker45
join:2003-10-18
Erie, CO
| reply to ToasterMan78
Re: Looking for the Common Thread in router problems
ToasterMan:
Thanks.
The PCs that I use at home are wired to the BEFW11S4. When it hangs, my wired connections are down (until I reboot).
My wife's PC (in another room of the house) connects wirelessly to the BEFW11S4.
Prior to my wife getting her PC (last Oct), I was in an all wired configuration (and did not have any problems - I used a different vendor's hub to connect my PCs).
When my wife bought her PC, I installed a BEFW11S4 to serve as a wireless AP and router. That's when I began having reliability problems caused by the BEFW11S4 hanging. I could probably move my wired PCs to a different (non-Linksys) device, but I'd still have the Linksys box to contend with for my wife's wireless connection (running wires to the room where my wife's PC is located is not an option ... I will need some kind of wireless AP in my network ... Linksys or otherwise). |
|
ChrisDAT
Google Keyword Compsysnyc
join:2002-02-26
Hollis, NY
|  reply to dellsweig
DHCP seems to be a contributor here... Does anyone have good performance with DHCP off --- You really dont need DHCP with less than 10 or so clients, it's easier and more stable to assign IPs, especially if you expect the machines to communicate with each other...
To add to that... For a "cheapie" NAT/Router, I would guess that the LinkSys suffers from poor packet buffering, both on the Switch/LAN side, and especially on the NAT/Router/Wan side, where a few, fat 100BaseTX boxes have to squeeze into a 10BaseT cable or DSL modem, which then squeezes into what amounts to a 1Mbit or so broadband connection... Routers hang and drop packets when their input buffer is full. I don't know if any linksys product sends source quench messages (probably not) to protect themselves, and many Windows implimentations have a tendency to free-flow (ignoring them anyway). The switches do not have (give) the ability to set the Duplex of the individual ports, this is important, because you really have no reason running full duplex (collision avoidance/detection is off here) on a small lan, and that can make the problem far worse since your cable/DSL modem is certainly half-duplex and supports CSMA/CD(sp.).
Overall the problem may be that the LinkSys may suffer from small buffers (not enough RAM) and trying to act like a big boy so that the little guy can take advantage of what is usually high-buck hardware... My suggestion, only use what you need, DHCP and logging require tables, not using them may free up more packet memory, especially if you're having big problems... Turn off that ZoneAlarm, the UPnP, and let the router concentrate on NAT.
|
|
ToasterMan78
Premium
join:2003-11-26
| reply to biker45
said by biker45  :
...running wires to the room where my wife's PC is located is not an option ...
I suspect you don’t want to damage your house by drilling to run wires. I had a friend who had Comcast cable TV installed, and before he could say “don’t drill through the hardwood floor” the Comcast guy did just that. |
|
dellsweig
Extreme Aerobatics
Premium,MVM
join:2003-12-10
Campbell Hall, NY
 ·Time Warner VOIP
·Vonage
 ·RoadRunner Cable
| reply to ChrisDAT
Chris
I have to agree... Logging, encryption, UPnP, lease renewal - all of the 'advanced' features of the linky add overhead. Overhead means CPU and memory resources. Every CPU cycle the CPU spends processing a logging trap is time spent NOT processing IP Packets. Our routers 'see' all traffic on the local ISP switch - it has to process all of your neighbors traffic to too. It may not route it but it has to look at the packet to 'see' if it is important. The more extra tasks you can turn off - the better the odds the router will survive. Alot of people have noticed that their problems started at some point in time - did your ISP's increase your bandwidth about that time? Mine did and thats when the lockups started.
Of the folks that sent me some of their config parameters - ALL of the 'working' routers had logging off, DHCP set to long intervals and no WEP or WPA
Just an observation........
I remember having to re-boot my computer all the time too - I would run too many programs at once.... Growing pains... |
|
someoneyoudonotknow
| dellsweig,
I use WPA exclusively and it works just fine. As far as microsoft not working with vendor xyz you are incorrect. At this point microsoft XP is the ONLY game in town if you want to use WPA.(I don't feel like paying for the odyssey client.) Admittedly the wirless client in XP is buggy. I must say I have rolled out a couple of these types of wireless networks for customers and it works perfectly. Now you must patch the XP wireless client twice for it to work properly.
As far as DHPC and UPnP and advanced features using CPU overhead. I have run NAT, Firewalling ACLs, DHPC server, syslog, SNMP polling and trapping, and quite a bit more but my memory is failing at the moment. The point is all of these proccesses were run on a platform with a 40 Mhz 386 Equivalent CPU with 4MB of RAM. (Cisco 2500 series) Now I do realize that these are Cisco boxes, I am just trying to show that yes the processes use CPU and memory it is not as bad as you might think. These small routers run with 125Mhz to 200Mhz processors in them! Hell 3 years ago my core router for 140,000 end users only had a 200Mhz processor! (MIPS R5000) The difference is the software running on the platform, and linksys does not spend the appropriate resources in this area to make things work properly. (Cisco/Juniper spend a large amount of money and software developement) Linksys boxes are way to cheap to recieve that kind of treatment.
James |
|
MSNhurts
join:2003-12-27
Los Alamos, NM
| reply to ToasterMan78
My router used to hang constantly, and then I upgraded to 1.44 or 1.45 (forget) - and it worked great. Then, in hopes of WPA, I upgraded to 1.5 - now all the convenience of wireless is lost because every 10 minutes (ok, not quiet that often) I have to get up and go reset the router. Is this the first upgrade since Cisco acquired linksys? I want to know who to be pissed at for releasing a firmware upgrade that re-introduced a problem that had, at one time, been solved. At least the firmware reminds me of who I can likely thank - Linksys *A division of Cisco, inc.* |
|
biker45
join:2003-10-18
Erie, CO
| reply to dellsweig
Most of the recent posts here seem to conclude that the "hanging" problem experienced by the Linksys BEFW11S4 (and/or any other "cheap" routers) may be due to these devices not having enough processing power and/or resources (RAM, etc) to handle the load. Thus, they periodically freeze/hang. Sounds reasonable to me. Although, it seems as though only the more recent models of Linksys hardware are experiencing this problem ... owners of the older models seem to be saying that their routers are solid. Could it be that Linksys has started using inferior components in their more recent models (this is only a conjecture, not an accusation).
Based upon the configs (of "working" routers) collected by dellsweig, I will disable logging and see if that helps to resolve the router hang problem I'm experiencing. I have already set my DHCP lease interval to 32767 (but that alone did not resolve the problem). If that does not work, I will just disable DHCP and assign static IP addresses.
I am using WEP, and really do not want to disable it. I live in a high density area where many of my neighbors' wireless APs are visible to me, so my AP must be visible to them. Even with its shortcomings, I'd rather have WEP enabled to stop the curious lurkers and rookie hackers, than just leaving my AP wide open.
In my case, the hang often (at least 90% of the time) occurs over night (between the time I power off my PCs and go to sleep, and when I reboot in the morning and find that the router has hung). During this time, there could be incoming packets destined for my router's IP address that overwhelm the router's resources and cause it to hang, but there is no traffic to/from the PCs on my LAN (they are powered off at the time). I have "Block Anonymous Internet Requests" and "Filter Multicast" both enabled to help reduce the exposure of my router. As dellsweig mentions, the problem may be caused by other traffic on my cable (not necessarily traffic destined for me, but traffic that my router must process to determine that it can ignore the packets).
MSNhurts asks whom to be angry at (Linksys or Cisco) for releasing a firmware upgrade that re-introduced a problem that had, at one time, been solved. My guess is: be angry at Linksys. Having been through a corporate "take over" (like Cisco buying Linksys), I believe it takes more than a year for a large parent corporation (Cisco) to impose its culture (and the resulting improvements in quality and reliability) on the newly acquired subsidiary. Cisco only bought Linksys early in 2003.
Cisco could have set a high objective for Linksys' bottom line, and to achieve their financial objective, Linksys may have found that they needed to use less reliable components in their newer models (and spend less staff resources solving firmware problems reported on their products). Again, this is only my conjecture. It certainly would be nice to get Linksys' side of this issue. |
|
rdhw
join:2002-09-21
Cambridge UK
| reply to dellsweig
said by dellsweig :
Our routers 'see' all traffic on the local ISP switch - it has to process all of your neighbors traffic to too.
No: on a cable modem system, none of your neighbour's traffic gets through your cable modem (if this were not so, the security implications would be immense). All that comes through your cable modem is traffic addressed to this particular customer, plus any broadcasts (ARP, DHCP) from the head end that are essential for the correct operation of IP networks. The bandwidth taken by those head-end broadcasts is trivial and not an issue.
The other things you mention (logging, UPnP, DHCP leases, etc) are also trivial in terms of network loading. Whatever is causing the problems you are suffering from, it isn't network loading from having these options active.
--
Robin Walker »homepage.ntlworld.com/robin.d.h.walker/ for broadband troubleshooting tips |
|
ChrisDAT
Google Keyword Compsysnyc
join:2002-02-26
Hollis, NY
|  reply to dellsweig
How about Cable -v- DSL?
I have DSL and a BEFSR41v2 router w/FW v1.45.7 and the one before that, that has been bulletproof since I got it in FEB 2002 --- No DHCP, no Multicast forwarding -- I don't do VPN, but I host several Apache servers (on different ports) supporting downloads, and TWO ShoutCAST streams that are busy 24/7... all this from a "modest" residential 640/128 Verizon DSL. It gets dead slow under load, but it does not die.
The modem is a Westell InfoSpeed Bellatlantic branded modem with one Flash upgrade.
Internally I run MS networking to share disks over IPX [Ethernet_802.3] just because it's faster.
I wonder if the connection type has anything to do with this puzzle?
(Just another thought: I wonder, what happens when the LinkSys DHCP expires leases while the clients are shut off? ie: how hard does it try to contact them? and what does it do when it cannot?) |
|
ToasterMan78
Premium
join:2003-11-26
1 edit | reply to biker45
said by biker45 :
...the "hanging" problem experienced by... routers... may be due to these devices not having enough processing power and/or resources (RAM, etc) to handle the load....
One problem is that manufacturers of home-class products (AFAIK) do not list the CPU, RAM, etc in the product specifications for their routers, etc. I wonder if there is any independent website(s) that would have this info? I suspect not. But it would probably be an eye-opener. |
|
biker45
join:2003-10-18
Erie, CO
| reply to dellsweig
After disabling Logging on my BEFW11S4 v4 (firmware 1,50) last night, I noticed that it did not hang (as usual) over night.
I was all set to celebrate (hoping to have found a resolution to the hang problem). Unfortunately, my router hung this afternoon.
So, it appears that disabling logging on the router is not the silver bullet that will kill the "router hang beast". SIGH. |
|
someoneyoudonotknow
| reply to rdhw
rdhw,
You are not correct. Cable data networks such as comcast are basically a hubbed architecture. Any traffic that is put out by ANYONE on your neighborhood cable node can be seen and sniffed by ANYONE else. Cable is not switched at this time it is simply repeated like a hub. With a router connected into a cable modem you mitagate this somewhat in that other folks can attack you machines directly but they can still see your packets. I sniff all of the time and you would not believe the traffic that you can see. I use comcast cable BTW
James |
|
George Kidd
join:2001-08-09
Vancouver, BC
| reply to dellsweig
@someone (anybody?) Hmmm if I get this right and a cable node is the same as a Hub then you can easily do the equivalent of a "Wiretap" on your neighbours. That should make it relatively easy to discover things like Passwords, Credit Card Numbers etc. How come the crooks are not doing a land office business on cable then? |
|
ToasterMan78
Premium
join:2003-11-26
| reply to someoneyoudonotknow
said by someoneyoudonotknow:
...Cable is not switched at this time it is simply repeated like a hub. ...[and you can therefore sniff your neighbors traffic]...I use Comcast cable...
My understanding is that switches are about the same price as hubs (at least for home users, I assume it carries through on the business end), and it would seem to be insane for a major ISP to use hubs on their network from a network-congestion point of view. Especially with hundreds of people potentially connected to a single node. |
|
ChrisDAT
Google Keyword Compsysnyc
join:2002-02-26
Hollis, NY
|  reply to dellsweig
You're both right, kinda:
Cable is a party line, but it is not really ehternet on the cable side, remember it is designed for cable TV, so it is not designed to be "secure." Your cable modem is the bridge that only forwards data destined for your internal network. That means that you cannot "snoop" packets from your side of the cable modem.
note: DSL works internally the way you expect because the POTS system is switched by nature -- that's one reason why DSL has a design advantage over cable, and that's the primary physical difference detween the two "under the hood." |
|
dellsweig
Extreme Aerobatics
Premium,MVM
join:2003-12-10
Campbell Hall, NY
·Time Warner VOIP
·Vonage
·RoadRunner Cable
| reply to biker45
Miker
When I see that replcaeing devices did not effect the situation - I tend to rule out that device as the culprit..
I think (and my own BEFW11S4's) back it out. That it is a cumulative thing. These devices may be running on the edge n some situations - especially in higher load cable situations.
Can you try leaving everything (PC's) turned on overnight, turn your logging off, turn your WEP off (create MAC access list if you are worried about unauthorized access), set the long lease interval and see what happenes. You can always work backwords from there.
My setup has been solid for weeks now since I made those changes..
Think of this simple analogy - you put bucket in the sink and run the faucet. You take a shot glass and one shot at a time, divert the water down the drain. You might be able to keep up with the water level in the bucket for a while. Eventually, you will have to reach away to do something (send a log trap or renew a lease). The water will rise. Eventually the water will win and the bucket will fill (buffer overflow and router freeze). If you speed the water up (ISP speed increase) or add some new overhead, the bucket fills faster.
The simple fact that you can set your watch by these failures suggest overhead as an issue |
|
dellsweig
Extreme Aerobatics
Premium,MVM
join:2003-12-10
Campbell Hall, NY
·Time Warner VOIP
·Vonage
·RoadRunner Cable
| reply to rdhw
RDHW
You are correct in saying that items such as logging, lease negotiations, encryption do not add to NETWORK overhead substantially.
We are talking about processing on a hardware device - all of these items take CPU and some take substantial memory (route tables, lease tables). Higher end routers can priorotize these tasks - for example, SNMP runs at a lower priority to prevent polling from effecting router performance - but it is doubtful these low-end devices have such ability. |
|
dellsweig
Extreme Aerobatics
Premium,MVM
join:2003-12-10
Campbell Hall, NY
·Time Warner VOIP
·Vonage
·RoadRunner Cable
| reply to ToasterMan78
said by ToasterMan78 :
said by someoneyoudonotknow:
...Cable is not switched at this time it is simply repeated like a hub. ...[and you can therefore sniff your neighbors traffic]...I use Comcast cable...
My understanding is that switches are about the same price as hubs (at least for home users, I assume it carries through on the business end), and it would seem to be insane for a major ISP to use hubs on their network from a network-congestion point of view. Especially with hundreds of people potentially connected to a single node.
If you think about it - a head end device may be responsible for 250 end user nodes. Of those - how many are actually allocated and in use in your neighborhood?? 20% or less - Total broadband users are only at 20% of households - that includes cable and DSL.
There is alot of traffic on the local segment of the ISP's LAN. You are using a shared resource. In some home installations,there may only be a few active drops - in some MANY active drops....
Bottom line - the more traffic present, the more traffic your router will have to handle on it's WAN side. From what I read on the boards, ALL the cheap routers have some type of lock-out problems - most likely under load.
AT the lab where I work, part of our certification of routers for OUR network is to load test them - crash them!! We make sure our configurations work - and tune config parameters if needed. Just remember the router does not have much of a CPU and memory (no P4 and gigs of mem). Think how easily you could crash a 386 box |
|
pooter
join:2002-11-26
Somerset, NJ
| The wireless Linksys I bought froze once a day (4 times in 4 days), any time of day with no discernable pattern (my setup details are in an earlier post.)
On Sunday, I ran a couple cable runs and put in a refurbished (wired) DLink DI-604. No freezes in 3 days (logging is enabled.)
For comparison's sake, I wish I could snag a new wired Linksys and see if that freezes on me. |
|
George Kidd
join:2001-08-09
Vancouver, BC
| reply to dellsweig
Well I find it quite interesting how Linksys carefully avoids things like Processor Clock Rate, Amount of Flash storage, Amount of RAM etc. in their Specifications. We always check this kind of stuff when we purchase a PC/MAC and so on. With Routers we are left to assume that as the costs of these items drop, then newer models will have faster processors and such. Over time loads on the Internet will have increased so one would expect routers need to be more robust to handle that.....Also increasing Wireless from 11 Mbps to 54 Mbps etc. must place a significant load on devices that handle the Traffic.
So the question is, what have the manufacturers done about all this if anything..... |
|
