diff --git a/content/blog/2022-02-14-personal-pbx.md b/content/blog/2022-02-14-personal-pbx.md index 316a1c1..7f46d4f 100644 --- a/content/blog/2022-02-14-personal-pbx.md +++ b/content/blog/2022-02-14-personal-pbx.md @@ -3,8 +3,38 @@ layout: page title: "I built my own private telephone network" description: "Nobody makes phone calls anymore" date: 2022-02-14 -tags: random 3d-pipeline +tags: project pbx draft: true extra: uses_katex: false + auto_center_images: true --- + +Over the past few months, I have built my own [internet backbone router](/blog/amprnet-bgp) (and an [internet exchange](https://ffixp.net)). So logically, the next step is to branch off into telephony... *right?* + +Eh, even if I never get any practical use out of any of this in the end, at least its content for the blog. + +## A simplistic introduction to telephone networking + +This is all coming from someone that has very little experience with the telephony world, but I *have* managed to make all my gear work, so this can't go too badly. + +As far as I have ever been concerned, the telephone network looks as follows: + +![The magical phone network](/images/posts/personal-pbx/magic_phones.png) + +But in reality, it looks a little more like the internet (I guess that makes sense, since dialup was a thing). + +![The magical phone network, with more phones](/images/posts/personal-pbx/phone_internet.png) + +The *Dark Magic* still exists, and I am still not entirely sure whats going on there. Presumably some kind of routing protocols exists to handle country codes and such, but I have had no need (yet) to explore this further. + +Continuing on with terminology, **Phones** are simply endpoints. Such endpoints could be cellphones, VOIP clients, automated answering machines, etc. **Carriers** are the same as the internet world. Big companies that own switching gear and phone number blocks they charge you to connect up to. + +Finally, **PBX**es. A [Private Branch eXchange](https://en.wikipedia.org/wiki/Business_telephone_system#Private_branch_exchange) (PBX) combines the concepts of routers and [NATs](https://en.wikipedia.org/wiki/Network_address_translation) in the telephony world. A PBX can be hardware-controlled, or software-defined through something like [Asterisk](https://en.wikipedia.org/wiki/Asterisk_(PBX)). + +I have personally used Asterisk a fair bit due to its heavy use in the Amateur Radio world as the backbone for repeater interconnections. More on this in a bit. + +## The goals for this project + + + diff --git a/static/images/posts/personal-pbx/magic_phones.dot b/static/images/posts/personal-pbx/magic_phones.dot new file mode 100644 index 0000000..4072e6f --- /dev/null +++ b/static/images/posts/personal-pbx/magic_phones.dot @@ -0,0 +1,7 @@ +digraph G { + rankdir=LR; + client -> magic -> client2; + client[label="Phone A"]; + magic[label="Dark Magic"]; + client2[label="Phone B"]; +} \ No newline at end of file diff --git a/static/images/posts/personal-pbx/magic_phones.png b/static/images/posts/personal-pbx/magic_phones.png new file mode 100644 index 0000000..5a326ab Binary files /dev/null and b/static/images/posts/personal-pbx/magic_phones.png differ diff --git a/static/images/posts/personal-pbx/phone_internet.dot b/static/images/posts/personal-pbx/phone_internet.dot new file mode 100644 index 0000000..4a3a119 --- /dev/null +++ b/static/images/posts/personal-pbx/phone_internet.dot @@ -0,0 +1,38 @@ +graph G { + rankdir=LR; + + client1 -- pbx1; + client2 -- pbx1; + + client3 -- pbx2, pbx1; + client4 -- pbx2; + + pbx1 -- carrier1; + pbx2 -- carrier1; + + carrier1 -- magic; + magic -- carrier2; + + carrier2 -- client5; + carrier2 -- pbx3; + + pbx3 -- client6; + pbx3 -- client7; + + client1 [label="Phone A"]; + client2 [label="Phone B"]; + client3 [label="Phone C"]; + client4 [label="Phone D"]; + client5 [label="Phone E"]; + client6 [label="Phone F"]; + client7 [label="Phone G"]; + + carrier1 [label="Carrier A"]; + carrier2 [label="Carrier B"]; + + magic [label="Dark Magic"]; + + pbx1 [label="PBX A"]; + pbx2 [label="PBX B"]; + pbx3 [label="PBX C"]; +} \ No newline at end of file diff --git a/static/images/posts/personal-pbx/phone_internet.png b/static/images/posts/personal-pbx/phone_internet.png new file mode 100644 index 0000000..353401d Binary files /dev/null and b/static/images/posts/personal-pbx/phone_internet.png differ diff --git a/templates/page.html b/templates/page.html index 792d813..37e8b17 100644 --- a/templates/page.html +++ b/templates/page.html @@ -42,6 +42,19 @@ MathJax.Hub.Config({tex2jax: {inlineMath: [['$','$'], ['\\(','\\)']], displayMat }] } + + + +{# Handle auto-centering request #} +{% if page.extra.auto_center_images %} + +{% endif %} {% endblock head %} {% block profile %} diff --git a/templates/section.html b/templates/section.html index af33977..a97c886 100644 --- a/templates/section.html +++ b/templates/section.html @@ -52,24 +52,25 @@ {# Blog posts #} {% if section.extra.inject_blog_posts %} {% endif %} {# RFCs #} {% if section.extra.inject_rfcs %} {% endif %} {% endblock content %} \ No newline at end of file