amigo_boy
join:2005-07-22
Tempe, AZ
 ·Cox HSI
 ·magicjack.com
4 edits | Tomato, QoS and "choppy voice"
Tomato 1.23 was released today.[1]
Improvements directly related to VOIP, and specifically for MagicJack are:
1. The ability to automatically detect RTP traffic is fixed.
The original Layer 7 (packet inspection) "rtp" filter didn't catch MagicJack voice traffic. The improved filter is temporarily contained under the name: "rtp-2".
This is what was discussed in another thread.[2] Presumably the improved filter will be included in the Layer 7 package (a higher level used by Tomato), and this "rtp-2" will disappear in a future version of Tomato.
But, for now, this makes Tomato much more usable for MagicJack users. I previously wrote an article describing how to use Tomato QoS using IP addresses (MJ proxy and vms servers, SIP and RTP respectively). This was confusing and problematic. Users had to jump through hoops to find the IP addresses for their regional servers. Additionally, when (not "if") MagicJack changes IP addresses it would break the QoS causing severe deterioration in voice quality. (The user might forget they have this IP address hardcoded, spending countless hours with MagicJack technical support.).
Now that the Layer 7 (packet inspection) filter identifies MagicJack's RTP traffic, the QoS rule can be created much easier, with virtually no risk that something will change causing the rule to break.
2. Addition of TCP Vegas.
This is a congestion avoidance algorithm (affecting only outgoing traffic?) built into the Linux kernal used by Tomato. DD-WRT (another free firmware) included this a few months ago. Users have been raving about it.
Some say it's better than QoS. Others say it works well with QoS. For example, specifying QoS outbound bandwidth=0 (to let the router give priority to packets), and enabling TCP Vegas to let it control the speed.
I haven't played with this yet. It sounds like it could be useful for people who's connection speeds vary (due to "power boost" or time of day). A downside of QoS is that you have to specify the lowest speed that your connection can regularly experience. (Some say you should specify 80% of that.). For someone with variable speed, they could miss a lot of bandwidth when it's available. TCP Vegas is supposed to allow the full speed to be used. But, it's not clear to me if this only applies to outgoing traffic, and/or how it could be used with QoS (no QoS limit, but QoS prioritization).
I'll write another post[3] showing how to setup QoS in Tomato 1.23 using Layer 7 (packet inspection).
Maybe another (later) showing how to flash a router.
[1] »www.polarcloud.com/tomato
[2] »Re: Giving priority to MJ traffic (Qos, Tomato firmware)
[3] Done. See: »HOW-TO: QoS and Tomato (fixes "choppy voice")
Mark |
