3 ms·

When it started, skype was p2p, and it wasn't anymore after microsoft acquired it. There are alternatives to skype, obviously. I don't understand why most of t

by jokoon 7y ago

When it started, skype was p2p, and it wasn't anymore after microsoft acquired it. There are alternatives to skype, obviously. I don't understand why most of those alternatives have a hard time becoming more popular. I'm not even sure those alternatives are p2p. Because it doesn't require a lot of bandwidth to run a p2p chat/video system, so it seems like it's pretty cheap.

JoeAltmaier 7y ago
"Tried to be p2p". Most of the time, our routers/APs defeated that. Skype would 'fall back' to using a server, which I believe it did 90% of the time.
- user5994461 7y ago
  It was P2P sometimes, like if you were running in a university or research institution. When skype got installed in there, it took over the university network and quickly became master node for the whole geographic area. For historic reasons, these organizations used to have many computers on public IP (they got large IP block when internet was created very long ago) and had amazing network connectivity.
- watermelon0 7y ago
  Are you sure? I don't know the specifics on how Skype used to work, but I'd assume that they were just using intermediary server to establish connection via NAT hole punching, and then proceed to communicate peer to peer.
  - JoeAltmaier 7y ago
    That's what doesn't work (NAT hole) depending on the endpoint router/firewall. More often than we think. It all depends on the filter used in the NAT logic in the router. They can depend on any of IP/PORT/Protocol/MAC of the source, and indeed that hadn't been commercially standardize for a long time. The trouble comes in 'handing off' the discovered address from the TURN server to the peer. The endpoint may or may not accept it, coming from a 'different guy' (the other endpoint now, instead of the TURN server).
- mrighele 7y ago
  I remember the old (pre-MS) skype being quite good at punching holes in firewall by using a number of tricks. Maybe it would not beat a determined sysadmin, but in many cases it was more than enough
- strictfp 7y ago
  I'm not convinced. It would use every trick in the book to punch holes; stun, upnp, sip, it's own protocol on top of udp, it would even send data over port 80 or 443. And if that failed Skype would use a third Skype client to open a port, or even route the calls through the third party. I always thought this was the major reason why Skype was so successful. It would penetrate almost any workplace firewall and "just worked" for most people. Shady, yes, but it worked.
  - JoeAltmaier 7y ago
    And all those tricks either worked for you (your endpoint), or they didn't. No middle ground. I worked 8 years in this environment (collaboration tools) and it was our holy grail to get p2p connections. We tried all those tricks and more. It worked a fraction of the time (at that time, 8 years ago).
    - strictfp 7y ago
      I guess most holes got patched. I worked with the same things around 2007.
- screamingninja 7y ago
  Where did you get this "90% of the time" statistic? "I believe"?
  - JoeAltmaier 7y ago
    Worked in the industry - wrote collaboration tools including media nodes, media endpoints, proxies and servers. Tried all the tricks in the book. Started out by running snoop tools on Skype to see what they tried, went from there. Lots of endpoints in the world flatly didn't allow p2p. Some whole nations disallowed entire protocols (Ireland, UDP). Some routers dropped every other UDP packet (ATT). Some reordered UDP (swapped packets in pairs). It was a total mess. Anyway we ended up with something ok, and a high-performance media node to handle most of the traffic which wasn't p2p.
lucideer 7y ago
It's relatively cheap in terms of raw hosting cost, but quite expensive in terms of maintenance / development effort, because p2p tends to be signficantly more complex than server-based. This expense is upfront (unlike hosting cost which tends to only ramp up along with your platform's success), so it makes it a difficult space to enter. Jitsi for example is making a good effort, but the quality/performance/stability still leaves something to be desired largely because it leans heavily on browsers to implement some parts of the complexities, and browser implementations are inconsistent / have bugs that the Jitsi devs aren't able to easily fix across the board.
jon-wood 7y ago
> I don't understand why most of those alternatives have a hard time becoming more popular. I think things are improving over time, but for a very long time "Skype Call" and "Video Call" meant the same thing in people's heads. Your product name appearing the dictionary as a synonym for the thing it does is a pretty powerful tool in customer acquisition and retention.

by jokoon 7y ago

JoeAltmaier 7y ago

"Tried to be p2p". Most of the time, our routers/APs defeated that. Skype would 'fall back' to using a server, which I believe it did 90% of the time.

user5994461 7y ago
It was P2P sometimes, like if you were running in a university or research institution. When skype got installed in there, it took over the university network and quickly became master node for the whole geographic area. For historic reasons, these organizations used to have many computers on public IP (they got large IP block when internet was created very long ago) and had amazing network connectivity.
watermelon0 7y ago
Are you sure? I don't know the specifics on how Skype used to work, but I'd assume that they were just using intermediary server to establish connection via NAT hole punching, and then proceed to communicate peer to peer.
- JoeAltmaier 7y ago
  That's what doesn't work (NAT hole) depending on the endpoint router/firewall. More often than we think. It all depends on the filter used in the NAT logic in the router. They can depend on any of IP/PORT/Protocol/MAC of the source, and indeed that hadn't been commercially standardize for a long time. The trouble comes in 'handing off' the discovered address from the TURN server to the peer. The endpoint may or may not accept it, coming from a 'different guy' (the other endpoint now, instead of the TURN server).
mrighele 7y ago
I remember the old (pre-MS) skype being quite good at punching holes in firewall by using a number of tricks. Maybe it would not beat a determined sysadmin, but in many cases it was more than enough
strictfp 7y ago
I'm not convinced. It would use every trick in the book to punch holes; stun, upnp, sip, it's own protocol on top of udp, it would even send data over port 80 or 443. And if that failed Skype would use a third Skype client to open a port, or even route the calls through the third party. I always thought this was the major reason why Skype was so successful. It would penetrate almost any workplace firewall and "just worked" for most people. Shady, yes, but it worked.
- JoeAltmaier 7y ago
  And all those tricks either worked for you (your endpoint), or they didn't. No middle ground. I worked 8 years in this environment (collaboration tools) and it was our holy grail to get p2p connections. We tried all those tricks and more. It worked a fraction of the time (at that time, 8 years ago).
  - strictfp 7y ago
    I guess most holes got patched. I worked with the same things around 2007.
screamingninja 7y ago
Where did you get this "90% of the time" statistic? "I believe"?
- JoeAltmaier 7y ago
  Worked in the industry - wrote collaboration tools including media nodes, media endpoints, proxies and servers. Tried all the tricks in the book. Started out by running snoop tools on Skype to see what they tried, went from there. Lots of endpoints in the world flatly didn't allow p2p. Some whole nations disallowed entire protocols (Ireland, UDP). Some routers dropped every other UDP packet (ATT). Some reordered UDP (swapped packets in pairs). It was a total mess. Anyway we ended up with something ok, and a high-performance media node to handle most of the traffic which wasn't p2p.

lucideer 7y ago

It's relatively cheap in terms of raw hosting cost, but quite expensive in terms of maintenance / development effort, because p2p tends to be signficantly more complex than server-based. This expense is upfront (unlike hosting cost which tends to only ramp up along with your platform's success), so it makes it a difficult space to enter. Jitsi for example is making a good effort, but the quality/performance/stability still leaves something to be desired largely because it leans heavily on browsers to implement some parts of the complexities, and browser implementations are inconsistent / have bugs that the Jitsi devs aren't able to easily fix across the board.

jon-wood 7y ago

> I don't understand why most of those alternatives have a hard time becoming more popular. I think things are improving over time, but for a very long time "Skype Call" and "Video Call" meant the same thing in people's heads. Your product name appearing the dictionary as a synonym for the thing it does is a pretty powerful tool in customer acquisition and retention.