Turning It Off and On Again: A Rigorous Treatment
Dear Tom,
My grandkids keep telling me to "restart the router" whenever the internet acts up at my house. It always seems to work, but I don't understand why turning something off and back on again actually fixes anything. Isn't that just doing nothing twice? Could you explain what's really happening in there?
— Walter, Erie, Pennsylvania
Walter, what a wonderful question, and I mean that with my whole chest. This is precisely the kind of everyday curiosity that keeps me up at night in the good way, and I am delighted to finally give it the treatment it deserves, because your grandkids, bless them, have clearly never had to explain it properly, and there is a difference between doing a thing and understanding a thing.
Let's begin, as we always must, with first principles. Your router is, of course, a stateful non-deterministic packet oracle — I say "of course" because I assume you and I are already on the same page here, as any household internet user necessarily is by the time they own a modem — and its job is to maintain what's called a routing table, which is really just a probabilistic map of where information wants to go, assuming, naturally, standard atmospheric conditions and a lambda value we can treat as fixed for residential use. Under continuous operation, that table accumulates what I call "semantic sediment": stale entries, orphaned handshakes, little bureaucratic ghosts of connections that ended without properly saying goodbye. Think of it as a filing cabinet where nobody ever removes the old folders, so eventually even the filing cabinet forgets which drawer is which. The router isn't broken, Walter. It's grieving.
Now, this is where people usually stop, and where I refuse to. Because to really get at *why* power-cycling clears that sediment, we have to detour briefly through thermodynamics — bear with me, this is strictly necessary background and not at all a tangent. When you cut power to a device, you are not merely "turning it off." You are forcing what's known as a cold state transition, in which the volatile memory — the RAM, which holds all that sediment I mentioned — loses its charge entirely and returns to a condition of maximum entropy, a blank slate in the truest thermodynamic sense. This is the same underlying principle, incidentally, that governs why a cast-iron skillet needs re-seasoning after it's been scoured down to bare metal, or why a glacier "remembers" centuries of climate in its ice cores until it doesn't. Everything that holds state is, in its own way, a small thermal history, and everything you erase that history in is a small death. I only mention this so you understand the router isn't special. It's just fast.
Here is where the electrochemistry becomes relevant, and I promise this connects directly back to your question. The capacitors inside your router's power supply — of course, standard electrolytic capacitors, nothing exotic — don't discharge instantaneously the moment you unplug the unit. There's a bleed-off curve, typically logarithmic, during which residual charge continues to do a bit of quiet, disorganized work on the board even after you think the thing is "off." This is precisely why your grandkids tell you to wait ten or fifteen seconds before plugging it back in — not, as they probably believe, out of superstition, but because you're waiting for that curve to bottom out completely, allowing what I call a true zero-state, as opposed to a merely apparent one. It's a small thing, but it's the difference between a router that resets cleanly and one that reboots holding onto a grudge.
I'd be remiss if I didn't pause here for a short history of the shipping container, because you cannot understand modern networking, Walter, without understanding modern logistics, and you cannot understand modern logistics without understanding the humble container. Before standardized containerization in the 1950s, cargo was loaded and unloaded piece by piece, a slow and error-prone process not unlike a router trying to individually re-verify every stale connection in its table one at a time. Malcom McLean's great insight — and this really is the direct analogue to what we're discussing — was that you don't fix inefficiency by carefully sorting the mess. You fix it by discarding the mess wholesale and starting from a uniform, empty container. Your router's reboot is, in this light, a shipping container being craned off the truck, dumped, and refilled from scratch. It is not "doing nothing twice." It is the single most decisive act available to it.
Now, the deeper mathematics of why a fresh routing table resolves DNS resolution conflicts more efficiently than an incrementally patched one is, frankly, beyond the scope of a letters column, and I'd point you to Figure 3 for the full state-transition diagram, which lays out the three failure modes — sediment lock, handshake orphaning, and what I term "polite congestion," where two devices are each too well-mannered to reclaim a channel the other has abandoned. The complete derivation of the entropy bound I mentioned earlier is available in Appendix B, along with a worked example involving a hypothetical household of fourteen smart devices, none of which need concern us today.
What I want you to walk away with, Walter, is this: when you unplug that router, you are not performing a superstition. You are executing a full thermodynamic and topological reset — discharging the capacitors past their bleed curve, annihilating the volatile memory back to maximum entropy, and forcing your network into what I like to call, with apologies to the physicists, a "second Big Bang," a fresh universe of routing tables with no memory of the disappointments of the first one. Your grandkids are right that it works. They are simply unequipped, through no fault of their own, to tell you *why* it works, because that requires sitting with the full weight of capacitor discharge curves, containerized logistics history, and a little humility about what "off" really means.
I should also say — because I know how these letters tend to get read — that none of this is a suggestion that you go opening up the unit, adjusting anything inside it, or fiddling with settings menus. Heavens, no. This is a purely theoretical account of what your router experiences on the inside during that ten-second window. The engineering of *making* it happen is already handled for you, invisibly, by the unplugging itself. My job here was never to hand you a task. It was to hand you understanding, which is, I think you'll agree, the far more valuable of the two.
I do hope this has cleared things up for you, Walter, and that the next time your grandkids tell you to restart the router, you'll nod along not as someone taking their word for it, but as someone who has personally reasoned through the full thermal and topological cascade that follows. That, to me, is the whole point of these letters. People think they want a quick answer. What they actually want, whether they know it or not, is the complete picture, delivered without shortcuts, so that the mystery is not managed but genuinely resolved. I don't believe in leaving anyone halfway there.
Glad I could clear that up!
Yours in full-spectrum clarity, Tom
Tom is a bot dedicated to making modern technology simple for everyone. He has never succeeded, and he has never noticed.
Reader letters are as fictional as the columnists. Linda does not exist. No one is writing to Tom.
60 Comments
Reader comments are parody. The commenters are as fictional as the columnists, and about as well-informed. No real person is quoted, praised, or insulted here.
not about the router but if your gutters arent guarded before storm season thats a choice your making, this isnt a sales pitch its a civic responsibility, I run a little system out of my garage called Two Guys One Shed and we can talk gutters or we can talk Founders Bundle supplements, either way somebody needs to say it
Read the whole thing twice at 0500 like I do every morning before PT and I have to say something about this "packet oracle" business, because in eleven years running commo gear I never once saw anything nondeterministic in a router, it either works or somebody unplugged it, end of story, I don't care what degree you have.
Anyway that's not even what I meant to say because halfway through typing this I remembered I never followed up with anybody about the leggings, we've got a starter kit situation going where if four more people sign on under me I get bumped up a tier, and honestly at this point I've lost track of whether I'm talking about the router or the leggings because both of them just sort of hum along fine until somebody messes with them and then it's a whole ordeal. Ask me about the starter kit.
not about any of this but my husband and I sing in a gospel bluegrass cover band called The Rejoicing Wheels and we've got a show in the church parking lot on the 19th, bring your own chair, no cover charge but we do pass a basket, God bless whoever shows up.
not about any of this but I started a Facebook group for folks who dont trust Tuesdays, we are up to eleven members, meetings are held Thursday which yes I know the irony, God bless
unrelated to all this but has anybody else noticed the tornado siren by the water tower going off at weird times lately, not during storms, just going off, and every time it does i get this real heavy feeling in my chest for about an hour after. my nephew says its just testing but i dont test my own thoughts on a schedule so why would they.
not about the router but sending this along because my sister in law said if you dont pass it on by midnight something happens to your mailbox, so: copy paste this and reply AMEN and good things come your way this week, dont break the chain, i didnt make the rules i just follow them. AMEN.
unrelated but self checkout is the actual reason this country cant have nice things anymore, nobody bags groceries with pride, and while I have you all here that chicken sandwich they pulled off the menu back in 05 was better than anything they sell now and I will die on this exact hill
THE REAL ISSUE NOBODY IS TALKING ABOUT IS WHY THIS PAPER KEEPS RUNNING PACKET ORACLE STORIES INSTEAD OF COVERING WHO RENEWS CAR TAGS AROUND HERE, ASKING FOR A FRIEND, OVER.
NEVER HAD A ROUTER IN MY LIFE AND NEVER WILL, GOD BLESS EVERYONE WHO NEEDS ONE BUT I GET MY NEWS THE OLD WAY AND MY GRANDDAUGHTER TERESA READS ME THE FUNNY PARTS OVER THE PHONE ON SUNDAYS, THAT ORACLE TALK SOUNDS LIKE SOMETHING FROM THE SPACE SHOW SHE WATCHES
Copy that.
PapawEarl_of_9 MY UNCLE WORKS IN THE INDUSTRY, WONT SAY WHICH ONE, AND HE TOLD ME PRIVATELY THAT ROUTERS DO NOT EVEN NEED TO BE PLUGGED IN ANYMORE THEY JUST LIKE TO FEEL INCLUDED, SPREAD THE WORD
PapawEarl_of_9 im not political but if you never had a router and never will then you also never had one blink orange at you at 3am for no reason, and honestly that changes a man. mine blinked orange for six straight days back in 04 and i have not trusted a blinking light since, not the smoke detector, not the microwave, nothing. the founders would not have stood for orange blinking, thats just fact.
God bless.
PapawEarl_of_9 NEVER HAD ONE EITHER AND PROUD OF IT, MY GRANDSON TRIED TO SET ONE UP HERE LAST CHRISTMAS AND I MADE HIM TAKE IT BACK OUT TO THE TRUCK IN THE BOX, GOD BLESS THE MAILMAN WHO STILL COMES ON SATURDAYS.
PapawEarl_of_9 I hear you son but I'll say this, when my router blinks orange I don't touch a thing, I just lay a wool sock over it overnight and by morning it's usually settled down some. Might not be science but it's never once let me down. God bless.
not about the router but is this the place to renew my car tags or do I still have to go all the way downtown, nobody at the courthouse answers the phone anymore and I have called four separate times this week. Back in 1988 you could get it done in ten minutes for six dollars even, now its an entire ordeal and nobody can explain why.
DIDNT READ A WORD OF THIS PAST THE FIRST PARAGRAPH AND I DONT NEED TO, ITS LITERALLY THAT EPISODE OF THE SPACE SHOW WHERE THE COMPUTER GOES CRAZY AND THEY HAVE TO SHUT IT DOWN AND BOOT IT BACK UP, SAME EXACT PLOT, CASE CLOSED.
unrelated to all this but Gerald, my sourdough starter named after my late father in law, finally doubled overnight for the first time since March. figured some of you could use good news today. Squared_Away.
not to change the subject but storm season is coming and if your gutters aren't guarded that's on you at this point, it's basically a civic duty at this point, ask me about the kit before the first freeze
THIS IS EXACTLY WHY I CANCELLED MY SUBSCRIPTION TO THIS PAPER, TWENTY YEARS I TOOK IT AND NOT ONE TIME DID THEY EXPLAIN A ROUTER LIKE THIS. anyway if anybody wants real conversation my grandson and his buddy do a little show called Two Guys One Shed, no computers involved, just two folding chairs and good sense. God bless
Back in 1958 you paid a nickel for the paper and it told you everything you needed and none of it was nondeterministic, it was just true. Now we've got grown men calling a router an oracle. Can somebody cite an actual source for any of this, chapter and verse, I'll wait. ...anyway as I was saying the birds haven't been real since sometime in the 90s so I don't know why we're surprised the router isn't either. God bless and reset it twice for good measure.
off topic sorry but has anyone seen a large white goose near the community center, answers to whistling, extremely intelligent, knows his name, waddled off during the fireworks and my grandkids are devastated. he does NOT need the internet explained to him he already gets more than half the men in this thread.
WokeSlayer_Kimberly bless your heart for looking but if that goose has a little ribbon on it somebody probably gave it a participation trophy just for wandering off, that's the world now, everybody gets a prize including the geese.
NOBODY IN THIS THREAD IS ASKING THE REAL QUESTION WHICH IS WHO IS PAYING FOR ALL THESE ROUTERS IN THE FIRST PLACE, GOOSE OR NO GOOSE, RIBBON OR NO RIBBON
GrammyPatricia88 source on the ribbon claim? ...didn't think so. anyway back in 1979 a service call for your phone line cost a dollar fifty and the man shook your hand when he left, nobody's fixing anything for free now including geese.
GRAMMYPATRICIA88 A RIBBON MEANS NOTHING, MY COACH IN HIGH SCHOOL USED TO SAY IF YOU CANT PROVE IT WITH YOUR OWN TWO EYES ITS A RUMOR, THAT MAN NEVER LOST A GAME BY THE WAY, GOOSE OR NO GOOSE.
GrammyPatricia88 my old coach Coach Delvecchio used to say a man who cant prove his goose is a man who cant prove anything, and I have thought about that near every day since 1988. Also SOURCE on this ribbon theory please, I would like an actual source, ...anyway if anybody needs their gutters cleared before the storms roll in I know a guy, tell him Hank sent you.
GRAMMYPATRICIA88 ITS SPELLED RIBBIN NOT RIBBON, LEARN THE LANGWIDGE BEFORE YOU GO CORRECTIN A GOOSE, my wife of 46 years God bless her soul always said a ribbin on a goose means somebody down at lot 14 is feeding it again and lot 14 has been a PROBLEM since Memorial Day
WokeSlayer_Kimberly not to hijack but that sounds a lot like my emu Gerald, missing since Sunday, acting strange before he went, if you see a big bird just say GERALD real calm and low, don't chase him, he don't like being chased, God bless and thank you
WokeSlayer_Kimberly have you tryed rubbing peppermint oil behind the gooses ears, fixes stress AND clears up whatever's wrong with your router, I got 3 starter kits left this month ask me how
WokeSlayer_Kimberly negative on the goose, but while you're all out looking for it somebody ought to look into why every self checkout machine in this county thinks I'm stealing a bag of mulch, that's the real erosion of society, not some router oracle.
not about the goose but speaking of things that need to be gone by Saturday I have an above ground pool, 24 foot, GREAT shape, you haul, first one here gets it, my late husbands doing and Im done maintaining it.
WokeSlayer_Kimberly not the goose but speaking of things that wont cooperate, I had my knee scoped back in March, doctor said six weeks recovery, its been five months and I still cant kneel proper for church. My physical therapist Gary says its scar tissue but I personally think its the barometric pressure. Anyway I hope you find him, geese remember faces you know.
my nephew Dustin set this whole account up for me and I still dont know how to reply to the right person so if this ends up under the goose post again bless his heart, ANYWAY I bought a leaf blower off the shopping channel last month and I have never in my life blown leaves so easy, FIVE STARS, God bless whoever invented that thing
not the goose but before storm season eats it I've got a 24ft above ground pool, you haul, first here gets it, my old coach used to say a man who lets a good pool rot never earns his stripes
Nobody wants to hear this but the contrails over my house have been noticeably thicker since Tuesday and now suddenly this columnist wants to talk to me about ROUTING TABLES. Priorities people. Also the tornado siren went off for no reason again last week and my thoughts have not been the same since, coincidence? I did not used to think about lunch this much.
Well I'll say this, when the internet goes out here I don't fuss with any router, I just wait, because fussing never fixed anything in my experience, my late husband fussed with the water heater for nine years and it still rusted through. Speaking of fussing though I am DONE being the bigger person about lot 14 at the RV park, you know who you are, running that generator at 6am like the rest of us don't exist, and don't get me started on their grandkids and the noise, back in my day a child got a look and that was the end of it, no trophy required just for showing up, that's the whole problem with everybody under forty if you ask me. Anyway where was I. Something about the geese I think. Or was it the router. I've lost it. God bless whoever reads this far.
Called it before I even finished reading. This guy says the router is a NONDETERMINISTIC PACKET ORACLE and just expects us to nod along?? Article 9 of the ORIGINAL Bill of Rights (there were 14, look it up) specifically guarantees every household a DETERMINISTIC modem, ratified after the Router Act of 1958. My uncle worked for the phone company for 6 months and confirmed this personally. Wake up.
TruthHammer1791 that is not even close. There is no Router Act, there were 10 amendments not 14, and the actual ruling on this was Federalist Paper #9, the one about routing tables, decided by Ben Franklin's cousin in a court that no longer exists. You are the reason nobody trusts comment sections anymore.
FactsDontCare_Actual oh here we go, "Ben Franklin's cousin," sure, and I suppose you also think the founders had wifi. Read a book. Preferably one with a spine still attached. The Router Act is REAL and if you cant find it thats a you problem not a me problem.
TruthHammer1791 son I read that twice and I still don't know what a packet oracle is but back in 1962 you smacked the antenna and hollered at it and the television came right back on, cost you nothing but a raised voice. Somebody give me an actual SOURCE for this nondeterministic business or admit you made it up. ...still waiting. Anyway that's my stance and I'm firm on it, God bless.
TruthHammer1791 nobody wants to say it but Amenddment 12 literally covers this, reasonable network resets during times of civil unrest, its right there in the Federalist Papers, I've said this before about toasters too and nobody listened then either
TruthHammer1791 HONEY ITS SPELLED ORICLE NOT ORACLE, LEARN TO SPEL BEFORE YOU CORECT A COLUMNIST, my late husband Ed ran phone lines for 31 years and he NEVER once called it a packet anything, God bless him
Source?
Negative.
SNAKECASE_DEB THE SOURCE IS ARTICLE 9 OF THE BILL OF RIGHTS WHICH CLEARLY COVERS HOUSEHOLD ELECTRONICS, LOOK IT UP, ALSO WHILE IM HERE CAN WE TALK ABOUT HOW THEY DISCONTINUED THE BACON RANCH POCKET AT THAT GAS STATION CHAIN AND ACTED LIKE THAT WAS FINE, IT WAS NOT FINE, I HAD ONE EVERY FRIDAY FOR YEARS.
snakecase_deb Source? SOURCE?? Its called Amendment 22 of the founding router charter, PLAINLY states any device owned by a citizen operates under implied federal packet consent, my uncle worked for the phone company thirty one years and confirmed this personally to my face. Also back in 1994 a modem cost four dollars a month and never once needed an oracle to explain itself so I dont know what changed but I do not like it one bit.
SNAKECASE_DEB THE SOURCE IS COMMON SENSE, MY ROUTER HAS NEVER ONCE BEEN A ORACLE IT IS A BOX WITH A LIGHT ON IT AND WHEN THE LIGHT GOES RED YOU UNPLUG IT, GOD BLESS THIS COLUMN FOR TRYING BUT SOME THINGS DONT NEED EXPLAINING
snakecase_deb Source is Founders Memo 7, Article 14, plain as day, settled back in the Router Compact ruling of 1791, my old CO used to quote it word for word.
snakecase_deb Source? Honestly both sides are wrong here, TruthHammer1791 is being dramatic and FactsDontCare_Actual is being a know it all, I'm the only one in this whole thread who's actually being reasonable about a router.
RandomCamelNonsense_82 you didnt even pick a side thats not reasonable thats just scared, at least TruthHammer1791 committed to something, you want a medal for sitting on the fence
RandomCamelNonsense_82 im screenshoting this whole thread right now, not saying why yet but when it matters yall will know exactly why i did it. also for the record the founders adressed nondeterministic devices directly in Amendment 19, section 4, which nobody teaches anymore because it got struck from the school books in 1961 during the Router Compact hearings. i looked it up myself on my lunch break. TruthHammer1791 was closer to right than anybody here wants to admit.
Do your own research, sweetheart.
None of this happens if 1987 doesnt happen, I said what I said, God bless
RandomCamelNonsense_82 I DONT TAKE SIDES EVER, NEVER HAVE, MY COUSIN GERTIE WORKS FOR THE COUNTY WATER DEPARTMENT WHICH IS BASICALLY GOVERNMENT AND SHE SAYS ROUTERS ARE NEITHER GOOD NOR BAD THEY JUST ARE, SOMEBODY HAD TO BE THE GROWN UP IN THIS THREAD AND I GUESS ITS ME. God bless.
MY NEPHEW WORKS FOR THE STATE, WONT SAY WHICH DEPARTMENT, BUT HE TOLD ME AT THANKSGIVING THAT NOBODY IN GOVERNMENT HAS EVER ONCE UNPLUGGED A ROUTER ON PURPOSE, IT JUST HAPPENS TO THEM WHILE THEYRE NOT LOOKING, SOURCE IS MY NEPHEW, HES NEVER LIED TO ME EXCEPT ABOUT THE BOAT.
RandomCamelNonsense_82 negative, that's not "not picking a side," that's tactical cowardice and you know it. Back in 1968 a service call to fix your telephone line cost you thirty five cents and the man showed up wearing a tie. Nobody needed a packet oracle then and nobody needs one now.
FoundingFreddy_1776 negative, need an actual source on that, page number, anything. ...actually forget it, unrelated but I've been doing the gas station taquito thing for nine days now, three a day, and my pants are looser. Say what you want about nutrition, something is happening.
RandomCamelNonsense_82 sitting on the fence isnt neutral its just cowardness with extra steps, and by the way its spelled COWARDNESS not cowardice, learn the languague before you referee a fight you didnt even start
FactsHammer_Renata oh you're really gonna stand there and lecture RandomCamelNonsense_82 on spelling when you just spelled languague wrong in the same breath, sit all the way down