{"id":258,"date":"2010-02-20T10:07:59","date_gmt":"2010-02-20T09:07:59","guid":{"rendered":"http:\/\/ccievoice.ksiazek.be\/?p=258"},"modified":"2025-01-11T18:28:06","modified_gmt":"2025-01-11T17:28:06","slug":"header","status":"publish","type":"post","link":"https:\/\/collaboration.ksiazek.be\/?p=258","title":{"rendered":"Header"},"content":{"rendered":"<p>Depending the Layer 2 technology that you use , the header can change :<\/p>\n<blockquote>\n<ul>\n<li>Ethernet Frame\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 =&gt; 18 bytes<\/li>\n<li>Frame Relay\/FRF.12\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0=&gt;\u00a0\u00a0 6 bytes<\/li>\n<li>MLP =&gt;<span style=\"text-decoration: line-through;\"> 6 bytes<\/span>\u00a0 <span style=\"color: #ff0000;\">13 bytes<\/span><\/li>\n<li>ATM =&gt; 5 bytes<\/li>\n<li>MLP over Frame Relay =&gt; 14 bytes<\/li>\n<\/ul>\n<\/blockquote>\n<p>For Layer 3 , you can use the following values<\/p>\n<blockquote>\n<ul>\n<li>IP Header = 20 bytes<\/li>\n<li>UDP Header = 8 bytes<\/li>\n<li>RTP Header = 12 bytes<\/li>\n<\/ul>\n<\/blockquote>\n<p>So it gives you the following amount<\/p>\n<blockquote>\n<ul>\n<li>IP+TCP+UDP Header =&gt; 40 bytes<\/li>\n<\/ul>\n<\/blockquote>\n<p>With CRTP enabled, you can then benefit of a huge saving of compression of this payload.<br \/>\nIndeed , from 40 bytes , you can decrease this payload from 2 up 4 bytes.<\/p>\n<p><!--more--><\/p>\n<p>Let&#8217;s look this with an IP Call in G729 , here is the bandwitdh used without CRTP enabled:<\/p>\n<ul>\n<blockquote><p>8000\u00a0 * ( 40 + 20) \/ 20 = 24000 bps = 24 Kbps<\/p><\/blockquote>\n<\/ul>\n<p>Now , let&#8217;s enable CTRP to see the saving :<\/p>\n<ul>\n<blockquote><p>8000\u00a0 * ( 2 + 20) \/ 20 = 8800 bps = 8,8 Kbps<\/p><\/blockquote>\n<\/ul>\n<p>You are performing a saving of more or less 70 %<\/p>\n<p>So you can see that on low links it is a benefit to enable CRTP in order to save your bandwidth.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Depending the Layer 2 technology that you use , the header can change : Ethernet Frame\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 =&gt; 18 bytes Frame Relay\/FRF.12\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0=&gt;\u00a0\u00a0 6 bytes MLP =&gt; 6 bytes\u00a0 13 bytes ATM =&gt; 5 bytes MLP over Frame Relay =&gt; 14 bytes For Layer 3 , you can use the following values IP Header [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[1,80,33],"tags":[59,85,81],"class_list":["post-258","post","type-post","status-publish","format-standard","hentry","category-non-classe","category-qos","category-written-theory","tag-ccie-voice-written","tag-header","tag-qos"],"_links":{"self":[{"href":"https:\/\/collaboration.ksiazek.be\/index.php?rest_route=\/wp\/v2\/posts\/258","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/collaboration.ksiazek.be\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/collaboration.ksiazek.be\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/collaboration.ksiazek.be\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/collaboration.ksiazek.be\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=258"}],"version-history":[{"count":1,"href":"https:\/\/collaboration.ksiazek.be\/index.php?rest_route=\/wp\/v2\/posts\/258\/revisions"}],"predecessor-version":[{"id":4496,"href":"https:\/\/collaboration.ksiazek.be\/index.php?rest_route=\/wp\/v2\/posts\/258\/revisions\/4496"}],"wp:attachment":[{"href":"https:\/\/collaboration.ksiazek.be\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=258"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/collaboration.ksiazek.be\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=258"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/collaboration.ksiazek.be\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=258"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}