Airpods Pro

▼ It's insane. I already spent nearly 800 euros on bluetooth headphones this year. And then Apple released the Airpods Pro, costing € 279 here in the Netherlands. And I couldn't help myself and bought a pair. So let's see how they compare.

My current bluetooth headphones / earbuds lineup is as follows:

Master & Dynamic MW60. These are big over-ear headphones that are bluetooth and wired.

Plantronics Backbeat Go 410. These are in-ear earbuds that connect to kind of a plastic horse shoe around your neck. This has the advantage that you can take them out and not lose them. (Which I actually had happen with some Jaybirds once.) They can take a wire, but that's pretty messy. And they have noise cancelation.

Jabra Elite 65t. These are "true wireless earbuds": one for each ear. As is usual for this type, they come in a charging case.

Now obviously these three are all very different in obvious ways. But they're also very alike in how the bluetooth works. You can pair them with a bunch of devices, and they'll stay connected to the last two devices. You can then play audio from either of those devices, and you'll hear it. When you stop playback and then start it on the other device, you'll hear audio from the other device. So you don't have to do anything to switch between those devices. However, using them with more than two devices means you have to go into bluetooth settings to reconnect to the headphones/earbuds, which gets old fast. (Although I think on iOS devices you can use a Shortcuts shortcut to make this easier.)

The MW60 has an actual switch to turn them on and off, which is great because it's fast. The others require a long press on one of the buttons. Speaking of buttons, they all have a play/pause/Siri button and volume up/down buttons. You can skip forward and backwards with a long press on the respective volume button.

With the earbuds there can be audio dropouts when I'm using them outside with the iPhone in my pocket, especially if there are no buildings close by.

The Airpods Pro

(Or Airpod Pros or simply APs.) What's really nice about these is that they're easy to put in and take out. You don't have to push them in as much as the other earbuds, I think they get a lot of support from your outer ear. Then again, if you take them out you pretty much have to put them in the charging case, because you can't turn them off. What?? When you do that, they are charged extremely rapidly, which just can't be good for those tiny little batteries.

When you press the button on the back of the charging case you can use the batteries widget in the today view of your iPhone or iPad to see the charge of the APs and the charge case. (When the charge of the left and right Airpods differs by more than 10% they show up separately.) Strangely, the little battery icon next to the headphones icon in the iOS status bar that you get for other bluetooth headphones/earbuds isn't there with the Airpod Pros.

The charge case hooks up to a lightning cable for charging, or you can use a wireless Qi charging pad. Unfortunately, that means you can't press the button to see how far along the charging is, but there's a motion sensor that lights up the LED on the front in you tap the case, which lights up amber when the charge is below 80%, green when above.

Apple has come up with a very nice way of pairing the APs: you simply open the case close to an iPhone (or iPad, I assume) and the iPhone will take it from there. The pairing is then synced to your other devices, including Macs and Apple TVs, using iCloud. Although Apple says you need the latest software to be compatible, all of this worked without trouble on my Macs that still run last year's Mojave. I guess under Catalina you get to turn on/off noise cancelation and transparency mode. You can also pair with non-Apple devices manually. On my iPhone 6 that runs iOS 12, I did that, and interestingly, the iPhone 6 can actually turn on and off noise cancelation through the bluetooth settings. Noise cancelation

I think especially people who are used to Apple's regular or "amateur" Airpods or similar earbuds that don't create a seal will be blown away by the noise cancelation, as they're used to hearing everything around them. Yes, the active noise cancelation is pretty good, but that only works on lower frequencies. For the high frequencies you need passive noise isolation. And that's something that the half a millimeter of silicone that the tips consist of just don't do very well. Same thing with the Plantronics. So basically all cars turn electric: you don't hear the engine anymore, but the road and wind sounds are still very prominent. Maybe that will get better if/when ComplyFoam comes up with foam tips for the APs.

I compared the passive noise cancelation of the Airpod Pros against that of the Jabra Elite 65t using the noise generator on mynoise.net. The Jabras blocked all the high treble and most of the mid and low treble, with the ComplyFoam tips doing slightly better than the included silicone tips. I then put a Jabra in one ear and an Airpod Pro in the other (with noise cancelation and transparency mode turned off). They both reduce the white noise significantly, but when I turn up the mid or high treble, it sounds like it only comes through on the Airpod side. For anything lower, the sound seems a bit off-center towards the Airpod Pro ear, but not by much.

Then I tried the active noise cancelation with an Airpod Pro in each ear. For the treble it actually seems to get a bit louder when you turn ANC on. The mids get reduced with ANC on and the low mids and anything below that are filtered out by the ANC increasingly effectively.

For now, cycling with a good headwind with cars zooming by is far from ideal: a lot of noise gets through. But the noise cancelation works very well when walking or riding public transit. The transparency mode where you hear outside sound through the microphones is very nice. But it's not new: the Jabras have it, too.

How the Airpods Pro are different form other bluetooth earbuds

The big difference with other current bluetooth headphones/earbuds is that the Airpod Pros won't connect to two devices in the same way. When you take them out of the case, they'll reconnect to the last used device. However, the good thing is that if you want to use them with a different (Apple) device, you simply select them as an audio target. The difference is that you don't have to set up a bluetooth connection first, so this is nice and easy. If you only use your headphones or earbuds with two devices, the behavior of the competition is better, because you don't have to do anything. But if you want to use them with three or more devices, the Apple way is better: yes, you need to tell each device to start using the APs, but that's pretty easy on all of Apple's OSes. The new device will break the bluetooth connection with the previous device if needed. (On old bluetooth headphones you actually had to disconnect from the previous device on that device first...)

On the iPhone I set up a shortcut that selects the APs as the audio target and then starts playing back the current episode in my favorite podcast app. That shortcut then goes in the today view, so it's only a few taps to go back to playing a podcast over the APs after using them with another device.

The APs have no volume buttons. Not a big deal, as I can just use the volume buttons on my iPhone. This also means that skipping forward/backward isn't done with a long press, which makes skipping part of a podcast really slow and thus annoying. Instead, this works the same as with wired earbuds: two clicks to skip forward, three to skip back. Where "click" means giving the stem of either Airpod Pro a quick squeeze. A long squeeze changes the noise cancelation / transparency setting and/or triggers Siri.

My verdict

They are expensive. I worry about the batteries. But they sound very good for earbuds and for wireless. They're comfortable to wear, and integrate well with the Apple ecosystem. It's also really nice that you can use either Airpod by itself while charging the other. They automatically go into transparency mode when you take one out, a really nice touch. With the Jabras, you can use the right one by itself, but not the left one.

In my experience, bluetooth headsets and earbuds are basically consumables: they last two, maybe three years. Of course not everyone listens to audio (mostly podcasts) as much as I do. But if you want wireless convenience, true wireless earbuds are really nice. And to me, an open design makes no sense: you'll be playing audio way too loud to get over all the background noise. Apple's Airpods Pro are a good choice, but if you don't want to spend that kind of money, the competition is certainly not half bad, either.

Permalink - posted 2019-11-26

Weblog reorganized

▼ I've reorganized my blog(s) and created subdomains under iljitsch.com for different topics. These are the ones:

all.iljitsch.com: all posts
www.iljitsch.com: most posts
iljitsch.com/nl/: posts in Dutch
iljitsch.com/en/: posts in English
news.iljitsch.com: news and announcements, anything timely
bgp.iljitsch.com: posts about BGP
ipv6.iljitsch.com: posts about IPv6 (or IPv4)
network.iljitsch.com: all posts related to networking, including home networks
home.iljitsch.com: all posts that aren't work-related (but including tech/gadget topics)
photo.iljitsch.com: photos
photography.iljitsch.com: posts about photography
tech.iljitsch.com: posts about tech topics and gadgets
audio.iljitsch.com: posts that relate to audio
transit.iljitsch.com: posts about public transport

Each of these pages has an RSS feed so you can subscribe if you are so inclined.

Posts will go to all the feeds that are relevant, so there will be duplicates if your RSS reader doesn't handle those.

And don't worry, muada.com isn't going anywhere. I just wanted to make a cleaner separation between different areas of interest.

Permalink - posted 2019-11-26 - 🇳🇱 Nederlandse versie

Routing theory: are link state and distance vector the only games in town?

▼ During his talk about 30 years of BGP, Geoff Huston said something along the lines of "someone should come up with another type of routing protocol besides distance vector and link state". That is of course too delicious a challenge to ignore.

But what would such new routing protocol type look like? It seems really strange that there would be exactly two ways to accomplish this task, and yet, as far as I know, nobody has ever proposed something truly different. And I can't think of anything. My conclusion: distance vector and link state routing protocols, with RIP and OSPF, respectively, as the archetypical examples, are not two completely separate ways to do routing, but rather, variations of basically the same thing.

This is the information that can be relevant for routing decisions that needs to distributed to all routers:

1. Adjacencies
2. Policy restrictions
3. Metrics
4. Reachability
5. Unreachability

Link state protocol OSPF doesn't do policies, and it floods updates that convey reachability between two routers (and thus implied adjacency) along with a metric. When the reachability is lost, this information is also flooded. That means that the path the OSPF updates follow can be different from the path towards a destination.

Distance vector protocol RIP doesn't deal with the reachability between pairs of routers, but rather, the reachability towards a destination. So there is no adjacency information, nor any policy information. Rather, if there is policy, it's implemented through a filter that removes reachability information. There's also no explicit unreachability information. Unlike with OSPF, updates aren't flooded throughout the network, but propagated over the links between routers.

Because a link state protocol knows all the adjacencies and reachability of the whole network, it needs to run an algorithm like the shortest path first / Dijkstra algorithm on each router to calculate paths through the network.

A distance vector protocol uses the distributed Bellman-Ford algorithm that propagates only the local notion of the best available path to the next router, so each router only has to choose between paths advertised by its neighbors.

Now let's look at BGP. BGP is definitely in the distance vector camp, but it does add a path for easy loop detection and an explicit unreachability update (withdrawal). Policy in BGP is traditionally applied locally, by simply hiding reachability and thus adjacency information from downstream neighbors.

However, a mechanism such as RPKI can be viewed as a policy distribution system. Here, the policy information isn't distributed by flooding or passing it downstream. Rather, the information is distributed out-of-band from a (more or less) central place. The internet routing registries can be viewed as central sources of adjacency information.

So we have five types of information to distribute, and three ways to distribute it (flooding, downstream, out-of-band) as well as simply not distributing and thus not using that information at all. So that's 5 x 4 = 20 possible way to accomplish routing.

Of course many of these combinations make very little sense. However, there are certainly places where we could change an existing protocol slightly and maybe gain some benefits. For instance, what if we add the idea of flooding unreachability updates to BGP? Currently, if a BGP router loses its BGP session to a neighbor, it executes the Bellman-Ford algorithm by selecting a new path. Of course if the old and the new path have the same now unreachable adjacency in common, that's not very helpful—an update replacing or withdrawing the new path will be on its way shortly. So why not add "X has lost reachability to Y" to an update, so the next router knows to look for a new path that doesn't include the X - Y adjacency?

But I don't think that we'll be able to carve out a workable new type of routing protocol from these 20 options. So link state and distance vector it is.

Permalink - posted 2019-10-15

Securing BGP: we can do it!

▼ In this month's edition of The ISP Column Why is Securing BGP just so Damn Hard? Geoff Huston asks himself exactly this question. He lists ten reasons. I don't agree with most of them: this is a solvable problem.

I think Geoff's main point is that BGP allows for arbitrary policies, which may lead to conflicting policies in different ASes and non-deterministic results.

And then, should we come up with new security mechanisms, it's hard to get them deployed because the business case for security (or business continuity in general, see IPv6) is hard: you need to spend money to keep what you already have.

So basically, BGP gives operators too much rope so they may end up hanging themselves. Interestingly, BGP's predecessor EGP was made to explicitly support the then (early 1980s) existing topology of the internet/ARPANET: a central backbone that all networks connect to in some way. In the early 1990s, the US government wanted to get out of the business of running the internet backbone, and BGP, which was created around that time, no longer makes any assumptions about the structure of the network.

This allows for conflicting policies, such as A trying to reach C through B, while B is trying to reach C through A. Obviously A and B can't both get what they want at the same time here.

Another ten years later, the work by Lixin Gao and Jennifer Rexford showed that if all networks apply a set of simple BGP policies that encode four different types of (business) relationships between networks, then BGP will reach a stable state. Hence their aptly titled paper Stable internet routing without global coordination.

Finally, in recent years we've realized that many unintended internet routing disruptions (route leaks) are caused by networks failing to properly translate their business relationships into BGP policies. See RFC 7908 types 1 - 4.

If we were to create BGP from scratch today, it would make sense to have baked-in policies for the four possible relationships between networks rather than expect every network operator to reinvent the wheel. The protocol can then check whether both sides of a BGP session agree on the type of relationship and alert the operators if that's not the case rather than let bad things happen. This would take care of most accidental route leaks.

However, that's not the BGP we have today. So what we need to do instead is detect those route leaks and filter out the affected routing information, see my blog post on fixing route leaks for an idea on how to extend RPKI to do this. With such an extension in place, RPKI can fix all six types of route leaks mentioned in RFC 7908.

That leaves the intentional BGP hijacks, that manipulate the BGP AS path to avoid the RPKI checks. BGPsec can fix this, but unfortunately that protocol is very heavy weight and it doesn't provide many benefits in partial deployment, so it's hard to see how the whole internet is going to adopt BGPsec.

But as more networks apply stringent (extended RPKI-based?) checks, there will be fewer and fewer places where rogue networks will be able to inject false AS paths and get away with it. Contiguous parts of the internet that perform these checks will thus be protected. That last part is crucial, because "boil the ocean" type solutions, which require the entire internet to adopt the solution before we gain any benefits, are a non-starter.

However, there is one last thing we should look at: rogue networks connecting to other networks using another network's AS number. That's a hefty investment in time and money for an attacker to be able to inject false information into BGP, but with other avenues closed this could start happening.

In conclusion: after more than two decades of experience and research, we understand BGP much better and we have a good idea of what needs to be improved. RPKI is a relatively successful example of a BGP security mechanism, while BGPsec is an example of something that's on the one hand too ambitious and on the other hand doesn't fix any immediate problems (i.e., route leaks). So I think we're in a good position to improve BGP security significantly over the next few years.

Permalink - posted 2019-09-20