My iChat isn't working

Question

All rigt I have been through this before. I am almost positive its my isps problem because I have asked everyone who has the sam e ISP to try it and it hasn't worked yet.
The videos aren't connecting

Answer 1

Hi,
It can depend on where you live.
Many rural areas a long way from town centers and the telephone exchange can make it difficult to either get decent phone lines good enough for DSL Internet connections or even a capable phone line at all (landline).
The same can be true of a Cable company.
There are inherent issues withe point to point WiFi similar to what you have.
For some internet protocols there is a back and forth process. The receiving server has to respond to certain packets and say it has received them before any more are sent. This can be fine for some as they do tend to speed up as they go.
However iChat requires that things are a lot faster then that for Video chat requiring an Instant On response.
This is even worse for Satellite connections. Here the latency can almost certainly make iChat Video impossible without specialist or specific arrangements. (it is possible to get services from the ISP that mask the delay (latency) by pretending it has received confirmation about packet delivery and continue as if more will be following.
For Land based options, particularly cable I would avoid Comcast and Road Runner.
Both these companies tend to manage their Bandwidth streaming in an effort to combat Peer to Peer File Sharing apps. Unfortunately iChat Video send s a lot of Data on a Peer to Peer basis (you can actually Log out of a Buddy List and continue the video) and can suffer because the stream gets slower and slower.
this is somewhat complicated by the Node based set up of cable connections.
You can consider it more like a LAN in that the service is then shared between several people and it can be effected by the business of your node. So it may not be just down to your Internet use, ut that of your neighbours as well.
I live in the UK and my answer is based on the posts over the last 6 years or so in the iChat 2 and 3 Forums where regular posts about these ISPs crop up.
iChat is limited by the Upload speed you have.
Try to make sure this is 500kbps or more as an ideal. Certainly better than 256k.
Apple state the minimum is 100k for an Video chat but this tends to be at the lower end of picture quality and frame rates.
Having said that the System Preferences > Quicktime > Streaming setting bears a direct effect on this. The Automatic setting is read by iChat as only 384k and could be limiting any speed you do have. It should be set at 1.5Mbps and iChat restarted if open.
For some ISPs that do practice bandwidth management, setting the Bandwidth limit in iChat > Preferences > Video section to 500kbps can help "Sneak under their radar" as it were (sometime as low as 200k), so it is not always a dead end option to use them.
What some ISPs do now is offer VoIP services (using a Landline or Internet Phone over the internet). This can be using a special phone, or adapter or router that has a phone socket as well as Ethernet ports for your equipment side of things. (in addition to any DSL phone line connection).
This tends to mean that they block port 5060-5063 which are reserved for SIP the protocol for such connection and what iChat 2 and 3 use to make Video and Audio only connections. On the whole these SIP ports used to be available and it is a money making thing that has caused the change. Often the company does not tell you. If you have received no notification they can often reopen them for free.
iChat 4 has changed the port that this happens on to port 16402 as first choice.
However some DSL ISPs use Thomson-Alcatel modems (usually combined Modem/Router with Wifi devices) that force SIP back to port 5060 and can mess things up again.
Summary.
Avoid Satellite
Avoid any sort of Wifi from your house to internet.
Try to pick an ISP that does not practice Data Stream Management.
Avoid those that offer VoIP services (it should not effect Leopard/iChat 4 but you may have other computers)
Avoid ISPs that offer Thomson-Alcatel devices - preferably get one that will allow you to either select your modem or even install your own choice.
Hope this helps.
12:54 PM Monday; July 27, 2009