Microsoft Azure: "Multiple international subsea cables were cut in the Red Sea"

(azure.status.microsoft)

179 points by djfobbz1 day ago

5 comments

djfobbz1 day ago
Multiple subsea fiber cuts in the Red Sea impacting global communicationsImpact SummaryStarting at 05:45 UTC on 06 September 2025, traffic traversing through the Middle East originating and/or terminating in Asia or Europe regions may experience increased latency due to multiple undersea fiber cuts in the Red Sea. The disruption has required rerouting through alternate paths which may lead to higher-than-normal latencies.This advisory is intended to raise awareness ahead of increased demand as the regions enter the start of its work week.Current StatusMultiple international subsea cables were cut in the Red Sea. Our engineering teams are actively managing the interruption via diverse capacity and traffic rerouting, while also discussing alternate capacity options and providers in the region.Undersea fiber cuts can take time to repair, as such we will continuously monitor, rebalance, and optimize routing to reduce customer impact in the meantime. We’ll continue to provide daily updates, or sooner if conditions change.This message was last updated at 19:30 UTC on 06 September 2025
- cr125rider23 hours ago
 The smart folks who keep these things running, despite failures like this, are incredible. Hats off to you all, good luck in the coming weeks as you have to deal with this.
 - ajsnigrutin20 hours ago
 <a href="https://www.bbc.com/future/article/20241014-the-deep-sea-emergency-service-that-keeps-the-internet-running" rel="nofollow">https://www.bbc.com/future/article/20241014-the-deep-sea-eme...</a>An article about people who fix thisAlso, the teams are quite busy:> "There are 150 to 200 instances of damage to the global network each year. So if we look at that against 1.4 million km, that's not very many, and for the most part, when this damage happens, it can be repaired relatively quickly."...> If a fault is found, a repair ship is dispatched. "All these vessels are strategically placed around the world to be 10-12 days from base to port,"...> To repair the damage, the ship deploys a grapnel, or grappling hook, to lift and snip the cable, pulling one loose end up to the surface and reeling it in across the bow with large, motorised drums. The damaged section is then winched into an internal room and analysed for a fault, repaired, tested by sending a signal back to land from the boat, sealed and then attached to a buoy while the process is repeated on the other end of the cable.
 - trelane19 hours ago
 > 1.4 million kmStrange way of writing 1.4gm.
 - bmicraft7 hours ago
 Should be 1.4Gm
 - trueismywork12 hours ago
 Do you also write gigagrams?
 trelane8 hours ago
 Usually I write "pounds," but what I usually write isn't the point.
 - pwdisswordfishz9 hours ago
 Gram-metres?
 trelane8 hours ago
 Hahaha.Hosted by my own petard. :)
 - adolph19 hours ago
 I wonder how much slack is left in the cable over its run in order to facilitate bringing it up for repair.
 - throwup23810 hours ago
 At first it’s an average of 1% slack across the entire run but up to 5% in rough terrain. They don’t use slack though for repairs, they lay down new cable between the bights that adds up to several miles to the length.
 - soupfordummies19 hours ago
 Now that’s what i call a service loop!
 - movedx21 hours ago
 BGP <3
 - marcosdumay21 hours ago
 Yes, but it's damn time people start upgrading to BGP ==3.
 - matt-p19 hours ago
 Most likely not. Almost certainly bfd or ldp/mpls
 - specproc22 hours ago
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 - crimsonnoodle5822 hours ago
 An act of terrorism is never smart or heroic.
 - specproc22 hours ago
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 - sporkxrocket21 hours ago
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 js21220 hours ago
 Free the hostages then we can talk
 sporkxrocket5 hours ago
 Yeah all of the Palestinians that Israel has been holding hostage since well before Oct 7th need to be freed.
typpilol22 hours ago
Were they cut on purpose or accident?
- betaby22 hours ago
 Cables in Red Sea got cut frequently. All the time it's the same story - anchor dropped where it should not. Similar stories happen near Singapore.
 - mandeepj22 hours ago
 > Cables in Red Sea got cut frequentlyOn land, we’ve call before you dig. I wish they could do something like call before you drop (anchor) training or just get the word out.
 - jvilalta21 hours ago
 They are usually marked on nautical charts.
 - jmkni3 hours ago
 Couldn't that be a security concern?
 - simplesimon8909 hours ago
 Some fishermen won't care as there are less ships where the cables are, they'll fish there. There are a lot of cables and fishing vessels in the Irish Sea.
 - anikom1521 hours ago
 (It’s not actually anchors.)
 - bmelton20 hours ago
 It very often _is_ an anchor, and they are usually dropped and dragged on purpose for the effect of cutting the cables which are clearly marked on charts as places to not drop anchor
 - gpm21 hours ago
 Why do you say that?I can't say I'm an expert on the matter, but my understanding from industry reporting on some likely intentional ones in the Baltic where that they were still unambiguously done with anchors. Just by someone intentionally causing the anchor to drop and drag along.
 simplesimon8909 hours ago
 Cable cuts are very common worldwide and are very rarely reported widely in the media ( that I've seen ) unless there's an opportunity to tie it to Russia. Then it's reported as suspicious or there's a paragraph in the article speculating about the security implications of purposeful attacks on communications infrastructure. IMO it's a ploy to generate anxiety about how much money is being spent on "security" i.e. the military, and how we ( Europe ) need to increase it.
 matt-p19 hours ago
 It's by far the most common.. but.. Multiple cables in this manner is IME /less/ likely to be an anchor, although it has happened.
 indigodiddy15 hours ago
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 - hulitu2 hours ago
 You mean no Russian or Chinese ships deliberating cutting cables on land like in EU ? That can't be /s
- saddat17 hours ago
 A captain told me once that it is silly to assume a big ship dropps it’s anchor accidentally unnoted
 - mmis100013 hours ago
 You need to run a whole procedure to get the anchor dropped. It can't be an "accident" in any means.And red sea is quite sunny currently (i just checked windy.com now) . There is absolutely no reason that they need to drop it out of nowhere.
 - cluckindan12 hours ago
 But it’s a somewhat believable cover story when you’re running military sabotage ops from a civilian vessel
- viraptor22 hours ago
 It's only been a few hours. I doubt anyone knows.
MengerSponge20 hours ago
Every subsea cable service interruption story is an excuse to share one of my favorite pieces of long-form technical history: Neal Stephenson's Mother Earth Mother Board:<a href="https://www.wired.com/1996/12/ffglass/" rel="nofollow">https://www.wired.com/1996/12/ffglass/</a><a href="https://news.ycombinator.com/item?id=20497098">https://news.ycombinator.com/item?id=20497098</a>
- staplung19 hours ago
 The Wired article is paywalled now unfortunately. Here's an archived version:<a href="https://web.archive.org/web/20210107003422/https://www.wired.com/1996/12/ffglass/" rel="nofollow">https://web.archive.org/web/20210107003422/https://www.wired...</a>The Verge also has a great article which is more recent and more specifically about a repair ship:<a href="https://web.archive.org/web/20240422050805/https://www.theverge.com/c/24070570/internet-cables-undersea-deep-repair-ships" rel="nofollow">https://web.archive.org/web/20240422050805/https://www.theve...</a>
upghost21 hours ago
Can they splice these? Surely the don't have to run a whole new cable?
- staplung19 hours ago
 They can but it's an involved process. Modern cables manage their slack very precisely - a complicated job in and of itself - and usually cannot be hauled to the surface without snapping them. So if the cable is not already cut (an anchor can damage a cable in a variety of ways short of physically snapping it) it will be cut while still on the bottom. The ends are then winched up and a splice is patched in but now there's a rather lengthy section of extra cable to deal with. They deal with that by laying it down precisely on the seabed in a nice sideways loop.
 - oniony9 hours ago
 So then you have extra latency for each repair.
 - 20after48 hours ago
 And extra attenuation / reflections.
- to11mtm21 hours ago
 I've only done land based fiber design, but I would assume based on my experience in that field that one of two things happens.First option, there's some slack somewhere nearby to do a pull nearby.If you ever pay attention to aerial poles, you'll see at various intervals things that are vaguely reminiscent of a snowshoe or tennis racket, in the industry they are in fact informally referred to as a 'snowshoe' and the entire purpose is to have some fiber to 'release' if a cut happens and a resplice is needed. [0]I'd -assume- there is an analogue for these in undersea cables...If not, well then you'd have to splice a length in and probably have the right sort of mechanism to ensure the cladding/etc stays contiguous (maybe even weld? IDK) but regardless you're probably talking... Actually wait yeah they've got this all figured out; <a href="https://www.youtube.com/watch?v=QiwidMEv8CM" rel="nofollow">https://www.youtube.com/watch?v=QiwidMEv8CM</a>[0] - Real world example, for instance if someone uses a fiber splice can for target practice.
- Waterluvian21 hours ago
 I think they raise the cable to the surface, splice it and sink it again.
 - bigiain19 hours ago
 I've read (or perhaps watched on YouTube) the same thing.Finding both ends of the cable to grab abd raise it took longer than the raise/splice operation.I suspect a sufficiently malicious attacker could intentionally cut the cable twice, so when the repair crew drag up one end of the cut they know about, the section between the cuts drags its other end away from it's cut-point making the second repair significantly more difficult...
 - staplung19 hours ago
 In most cases they can easily figure out approximately where the break is on the line by simply measuring the resistance in the cable's conductors (they have more than one but the big one caries a 10,000V feed to power the repeaters). A double cut would probably show up as resistances that didn't sum to the proper total.
 - matt-p19 hours ago
 You can only practically do that optically e.g through OTDR. You can't TDR steel conductors exposed to the ocean 500KM away with a ohm meter and a Murray loop, to even have a chance you need to put low voltage on it and it's not even close to as accurate.
 robocat13 hours ago
 Rubbish. TDR is not a Murray loop.<a href="https://en.m.wikipedia.org/wiki/Murray_loop_bridge" rel="nofollow">https://en.m.wikipedia.org/wiki/Murray_loop_bridge</a><pre><code> Spread-spectrum time-domain reflectometry (SS-TDR) is often used to locate and characterize a fault on active cables. Traditional time-domain reflectometry, which sends signals down a conductor to determine where any impedance discontinuities are by timing any reflections that come back from any impedance discontinuities along the way, can’t be used on in-use undersea cables thanks to the high voltages involved. SS-TDR, which was originally developed to detect faults in the wiring of airplanes using 400-Hz AC power, uses modulated pseudo-noise (PN) signals rather than a plain square wave pulse. The signals still bounce off any impedance changes introduced by damage, but an algorithm is used to correlate the returned PN codes with what was sent and when, making it easier to make measurements in a noisy environment. Optical TDR can also be used to locate fiber breaks </code></pre> <a href="https://hackaday.com/2024/07/30/undersea-cable-repair/" rel="nofollow">https://hackaday.com/2024/07/30/undersea-cable-repair/</a>A little knowledge goes a long way
 - pixl9719 hours ago
 Cutting twice wouldn't be an issue, they can send a signal from both ends to get a reflection of how much of the cable is dead.
- ajsnigrutin20 hours ago
 <a href="https://www.bbc.com/future/article/20241014-the-deep-sea-emergency-service-that-keeps-the-internet-running" rel="nofollow">https://www.bbc.com/future/article/20241014-the-deep-sea-eme...</a>An article about such repairs (150-200 yearly)> To repair the damage, the ship deploys a grapnel, or grappling hook, to lift and snip the cable, pulling one loose end up to the surface and reeling it in across the bow with large, motorised drums. The damaged section is then winched into an internal room and analysed for a fault, repaired, tested by sending a signal back to land from the boat, sealed and then attached to a buoy while the process is repeated on the other end of the cable.
pagansRpedos19 hours ago
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