Covad T1 Speed and Latency Test Plus Overview

Tom Keating : VoIP & Gadgets Blog
Tom Keating
| VoIP & Gadgets blog - Latest news in VoIP & gadgets, wireless, mobile phones, reviews, & opinions

Covad T1 Speed and Latency Test Plus Overview

CovadAs part of the Covad Blogger's program, Andy setup several industry bloggers with a Covad T1. Greg, Phoneboy, and Ken Camp, have all covered their experiences with using a Covad Internet T1 connection. On a related note, Rich Tehrani had an interview with Covad's Jeff Ahlquist, Vice President of Corporate Development and Strategy that is definitely worth checking out.

Anyyway, last week, I had my T1 installed and configured. One of the first things I did was perform a bandwidth speed test. I went to and ran an online bandwidth test. First the download test ran and I got 1,450Kbps, which is pretty close to a standard-rated 1.544Mbps (1544Kbps) T1 connection. Then the upload (upstream) test ran and to my shock I was only getting 444Kbps. This isn't nearly as fast as it should be. I tried another speed test website and got similar results.

I fired off an email to Andy explaining my benchmark results and asked him if I received a "true" T1. He responded that it was a true T1 and that there was no way my upstream should be that slow. He suggested I contact Covad technical support, but before I did that, I decide to play around with my Linksys WRT54G router.

Just by chance I happened to click the Applications & Gaming menu in the Linksys Web-based admin and noticed a QoS tab. I clicked on the QoS tab and noticed I had QoS turned on and configured to give my now defunct Cisco ATA-186 "high priority". I set my ATA-186 to "high priority" over a year ago when I was having VoIP quality issues with Vonage. I forgot I had QoS turned on, but surely having QoS enabled wouldn't affect my upstream bandwidth, would it? The Linksys router should be smart enough to see that there is no Vonage device with the MAC address specified currently receiving/transmitting packets, and therefore the router should give all the bandwidth to any application that wants it. Seems logical, right?

Wrong! I turned off QoS and then ran another bandwidth test and voila, I had symmetric speeds of about 1,450Kbps. Actually, the upstream was slightly faster than the downstream on my first test with 1,468Kbps vs. 1,450Kbps. I joked with Andy, "Well, it is a cheap residential WRT54G router, so I guess I can’t expect commercial-grade QoS with ToS bits, etc." Here's a screenshot of the Linksys QoS setup screen showing how I had the Vonage ATA device set to high priority. (click for Larger Image)
Moral of the story - If you want maximum performance leave QoS turned off if using a Linksys router. Seems counter-intuitive doesn't it?

However, if I still had Vonage and used a bandwidth hog such as P2P client (eMule, Bittorent, etc.) I would need to leave QoS turned on so the voice packets get priority. It would appear as a side effect I would lose roughly 1,000Kbps of upstream bandwidth, which really sucks. Maybe Linksys has new firmware for the WRT54G, which resolves this issue. I'm running v3.03.6 currently.

In any case, I did one other test to check the latency of the Covad T1, which is actually more important than raw bandwidth if you're doing VoIP or videoconferencing. As a benchmark test, I pinged and TMC's T3 router. Here are the results of an approximately 10min ping test:

TMC T3 Router
Packets: Sent = 1075, Received = 1075, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 10ms, Maximum = 921ms, Average = 100ms

Ping statistics for
Packets: Sent = 1017, Received = 1016, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 13ms, Maximum = 37ms, Average = 18ms

Pretty impressive latency numbers, especially when pinging since it's maximum latency was 37ms and it's average was an amazing 18ms. It would appear that Covad sits very close to where Yahoo connects to the Internet. Obviously, since Covad is a carrier they sit near the main fat pipes. Yahoo gets massive traffic, so I'm sure they connect just a few short hops from the fat pipes. I'm sure both have multiple connections across the country and of course Covad has Tier-1 peering agreements, which guarantees that cross-country traffic is super fast.

Overall,  I'm very happy with my Covad T1 experience. The installer was friendly and courteous. The latency is excellent and the bandwidth, in particular the upstream is much better than my DSL. I asked the Covad installer about Covad offering fiber in the near future, since Verizon is quickly deploying their FiOS service and AT&T is going gangbusters with their U-verse service. Both of these competitors can provide Triple Play packages (voice, video, data).

He mentioned he was aware of Verizon FiOS and that Covad currently doesn't offer a fiber solution, but hinted that FiOS was helping to push Covad to provide fiber in the very near future. I think AT&T and Verizon are starting to drive some of the Tier-2 carriers to provide fiber to the home (FTTH) or provide a hybrid-fiber/copper approach like AT&T's U-verse is taking. And that my friends is great news for residential customers which are clamoring for more bandwidth and more services at an inexpensive price point.

Related Articles to 'Covad T1 Speed and Latency Test Plus Overview'

Featured Events