I work in a small office and have fallen into the role of network support based on knowing enough about networking to be dangerous. Our office is moving from DSL to a T1. Were using Asterisk as our PBX and I'm looking for hints or resources that might help me make the transition as error free as possible. Are there well known gotchas that I shoud be aware of? Thanks in advance, Richard Stuppi richard at stuppi.com 626-221-8010
On Sun, Sep 12, 2010 at 10:43 AM, Richard Stuppi <richard at stuppi.com> wrote:> I work in a small office and have fallen into the role of network support > based on knowing enough about networking to be dangerous. > > Our office is moving from DSL to a T1. Were using Asterisk as our PBX and > I'm looking for hints or resources that might help me make the transition as > error free as possible. > > Are there well known gotchas that I shoud be aware of? > > Thanks in advance, > > Richard Stuppi > richard at stuppi.com > 626-221-8010 > > >You should be more specific, A)Are you switching from voip over DSL to voip over T1 B) ... or using the T1 for phones? C)Are you switching from analog lines + DSL to just a T1 for voice and data? -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.digium.com/pipermail/asterisk-users/attachments/20100912/e202e66d/attachment.htm
-----Original Message----- From: asterisk-users-bounces at lists.digium.com [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Steve Edwards Sent: Sunday, September 12, 2010 5:57 PM To: Asterisk Users Mailing List - Non-Commercial Discussion Subject: Re: [asterisk-users] Moving from DSL to T1 On Sun, 12 Sep 2010, Kevin Keane wrote:> What really matters is the latency, and T-1 is a huge improvement over > DSL in that area. The easiest way to measure latency is the ping time > to a server that is ?close to you? Internet-wise. A DSL has latencies > of between 40ms (if it?s extremely good and not too many other people > are using it) and 1000ms (if there is a problem somewhere). A good T-1 > may have latencies as low as 5 ms or so. Also, with a T-1 the > bandwidth is guaranteed and bidirectional. With a DSL line, you may > get burstable bandwidth ? you don?t actually have that bandwidth, you > just get to compete for excess bandwidth with your neighbors.>You are confusing DSL with cable.Both, actually. The latency numbers are actual numbers measured at a customer site. The sharing of excess bandwidth also happens with both, just in different places.
-----Original Message----- From: asterisk-users-bounces at lists.digium.com [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Hans Witvliet Sent: Monday, September 13, 2010 12:13 PM To: asterisk-users at lists.digium.com Subject: Re: [asterisk-users] Moving from DSL to T1 On Mon, 2010-09-13 at 00:32 -0700, Kevin Keane wrote:> > > Latency also is the reason VoIP does not work at all over satellite > > connections even though they tend to have plenty of bandwidth. > Please define "does not work at all over satellite" ??? > Sure, it is not studio HIFI quality, but is th same quality as you get from official commercial telco providers. > We still have voip over S-band and X-band satelites running NOW between NL and afghanistan. All the people are more than satisfied. > > ********** > Should have been more specific. I was talking about Internet over satellite in the USA. I believe those are geostationary TV satellites. I am not familiar with S-band and X-band, but assume they are in lower orbit. That would explain how it can work for you. >No these are also geo-stationary (same altitude, so same delay), commercial and military satelites, ************** In that case, my guess is that they have a dedicated channel for the voice, maybe even some kind of clocking mechanism. Some T-1 lines here in the USA also have that (one more reason why T-1 works better than DSL/Cable for VoIP). The consumer internet satellite services just mix all kind of Internet traffic, so one packet may have a very low latency while the next one may have a much higher latency, or get lost altogether. Another thing about the consumer satellites is that they are probably optimized for TCP rather than UDP. For TCP, they are using huge retransmission window sizes. That allows large chunks of data to arrive without waiting for confirmation, and the satellite can organize the data into a stream. With UDP, each packet basically stands on its own. Just a guess about another area where these two could be different.