{"id":5236,"date":"2023-11-02T20:13:00","date_gmt":"2023-11-02T14:43:00","guid":{"rendered":"https:\/\/ipwithease.com\/?p=5236"},"modified":"2025-04-01T19:05:49","modified_gmt":"2025-04-01T13:35:49","slug":"mpls-label-explained","status":"publish","type":"post","link":"https:\/\/ipwithease.com\/mpls-label-explained\/","title":{"rendered":"MPLS Label Explained"},"content":{"rendered":"<div id=\"ipwit-1779040131\" class=\"ipwit-before-content ipwit-entity-placement\" style=\"width: 728px;\"><div class=\"ipwit-adlabel\">Google ADs<\/div><div style=\"height: 90px;\"><script async src=\"\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-1375203873676133\" crossorigin=\"anonymous\"><\/script><ins class=\"adsbygoogle\" style=\"display:inline-block;width:728px;height:90px;\" \ndata-ad-client=\"ca-pub-1375203873676133\" \ndata-ad-slot=\"9359532231\"><\/ins> \n<script> \n(adsbygoogle = window.adsbygoogle || []).push({}); \n<\/script>\n<\/div><\/div><h2>What is MPLS Label?<\/h2>\n<p><strong>MPLS<\/strong> stands for <strong>Multiprotocol Label Switching<\/strong>. It is termed as a <span style=\"color: #0000ff;\"><a style=\"color: #0000ff;\" href=\"https:\/\/www.forcepoint.com\/cyber-edu\/mpls-multiprotocol-label-switching\" target=\"_blank\" rel=\"noopener\">layer 2.5 technology<\/a><\/span> widely used across the service provider backbones to label switch different customer traffic. The traffic inside the ISP backbone is then label switched rather than being IP switched. In MPLS a<strong> Label<\/strong> of length 32 bits is inserted in between the IP header and the Ethernet header.<\/p>\n<h3>Components of MPLS Label<\/h3>\n<p>The various field of an MPLS label and there explanation are as below:<\/p>\n<p id=\"nHtPyzD\"><img decoding=\"async\" width=\"954\" height=\"263\" class=\"alignnone size-full wp-image-5238 \" src=\"https:\/\/ipwithease.com\/wp-content\/uploads\/2018\/07\/img_5b47b49dcc97a.png\" alt=\"\" title=\"\" srcset=\"https:\/\/ipwithease.com\/wp-content\/uploads\/2018\/07\/img_5b47b49dcc97a.png 954w, https:\/\/ipwithease.com\/wp-content\/uploads\/2018\/07\/img_5b47b49dcc97a-300x83.png 300w, https:\/\/ipwithease.com\/wp-content\/uploads\/2018\/07\/img_5b47b49dcc97a-600x165.png 600w, https:\/\/ipwithease.com\/wp-content\/uploads\/2018\/07\/img_5b47b49dcc97a-150x41.png 150w, https:\/\/ipwithease.com\/wp-content\/uploads\/2018\/07\/img_5b47b49dcc97a-400x110.png 400w, https:\/\/ipwithease.com\/wp-content\/uploads\/2018\/07\/img_5b47b49dcc97a-768x212.png 768w\" sizes=\"(max-width: 954px) 100vw, 954px\" \/><\/p>\n<p><strong>Label Value: <\/strong><\/p><div id=\"ipwit-126152237\" class=\"ipwit-content ipwit-entity-placement\"><div class=\"ipwit-adlabel\">Google ADs<\/div><script async src=\"\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-1375203873676133\" crossorigin=\"anonymous\"><\/script><ins class=\"adsbygoogle\" style=\"display:block;\" data-ad-client=\"ca-pub-1375203873676133\" \ndata-ad-slot=\"2483378328\" \ndata-ad-format=\"auto\"><\/ins>\n<script> \n(adsbygoogle = window.adsbygoogle || []).push({}); \n<\/script>\n<\/div><br style=\"clear: both; display: block; float: none;\"\/>\n<p>As the name suggests it is where you will find the actual value of the label.<\/p>\n<p>0-15 are the reserved labels and are never made available for allocation. \u00a0Label 0 is the explicit NULL label, whereas label 3 is the implicit NULL label. Label 1 is the router alert label, whereas label 14 is the OAM alert label.<\/p>\n<p><strong>EXP:<\/strong><\/p>\n<p>These are the three experimental bits. These are used for QoS, normally the IP precedence value of the IP packet will be copied here or the first three DSCP bits will be copied here.<\/p>\n<p><strong>S: <\/strong><\/p>\n<p>This is the \u201cbottom of stack\u201d bit. In MPLS it\u2019s possible to add more than one label. Suppose there are three labels stacked together then the first two labels will have this field as \u20180\u2019 while the bottom label will have this bit set with a value of \u20181\u2019.<\/p>\n<p><strong>TTL: <\/strong><\/p>\n<p>Just like in the IP header, this is the time to live field. You can use this for traces in the MPLS network. Each hop decrements the TTL by one.<\/p>\n<h3>MPLS Label Sample<\/h3>\n<p>Sample of the packet capture showing the MPLS label embedded between Ethernet header and IP header.<\/p>\n<p id=\"cPZYVsy\"><img decoding=\"async\" class=\"wp-image-5239 aligncenter\" src=\"https:\/\/ipwithease.com\/wp-content\/uploads\/2018\/07\/img_5b47b4e90de35.png\" alt=\"\" width=\"685\" height=\"334\" title=\"\" srcset=\"https:\/\/ipwithease.com\/wp-content\/uploads\/2018\/07\/img_5b47b4e90de35.png 898w, https:\/\/ipwithease.com\/wp-content\/uploads\/2018\/07\/img_5b47b4e90de35-300x146.png 300w, https:\/\/ipwithease.com\/wp-content\/uploads\/2018\/07\/img_5b47b4e90de35-600x293.png 600w, https:\/\/ipwithease.com\/wp-content\/uploads\/2018\/07\/img_5b47b4e90de35-150x73.png 150w, https:\/\/ipwithease.com\/wp-content\/uploads\/2018\/07\/img_5b47b4e90de35-400x195.png 400w, https:\/\/ipwithease.com\/wp-content\/uploads\/2018\/07\/img_5b47b4e90de35-768x375.png 768w, https:\/\/ipwithease.com\/wp-content\/uploads\/2018\/07\/img_5b47b4e90de35-450x220.png 450w\" sizes=\"(max-width: 685px) 100vw, 685px\" \/><\/p>\n<h2><span style=\"color: #ff6600;\">Continue Reading:<\/span><\/h2>\n<p><span style=\"color: #0000ff;\"><em><strong><a style=\"color: #0000ff;\" href=\"https:\/\/ipwithease.com\/mpls-75-interview-questions\/\" target=\"_blank\" rel=\"noopener\">Top 75 MPLS Interview Questions &amp; Answers<\/a><\/strong><\/em><\/span><\/p>\n<p><span style=\"color: #0000ff;\"><em><strong><a style=\"color: #0000ff;\" href=\"https:\/\/ipwithease.com\/mpls-cheatsheet\/\" target=\"_blank\" rel=\"noopener\">MPLS Cheatsheet<\/a><\/strong><\/em><\/span><\/p>\n<h3>ABOUT THE AUTHOR<\/h3><div id=\"ipwit-2731405077\" class=\"ipwit-post-end-ad ipwit-entity-placement\"><script async src=\"\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-1375203873676133\" crossorigin=\"anonymous\"><\/script><ins class=\"adsbygoogle\" style=\"display:block;\" data-ad-client=\"ca-pub-1375203873676133\" \ndata-ad-slot=\"2483378328\" \ndata-ad-format=\"auto\"><\/ins>\n<script> \n(adsbygoogle = window.adsbygoogle || []).push({}); \n<\/script>\n<\/div><br style=\"clear: both; display: block; float: none;\"\/>","protected":false},"excerpt":{"rendered":"<p>What is MPLS Label? MPLS stands for Multiprotocol Label Switching. It is termed as a layer 2.5 technology widely used [&hellip;]<\/p>\n","protected":false},"author":782,"featured_media":23289,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[177],"tags":[79],"class_list":["post-5236","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-routing-switching","tag-mpls"],"_links":{"self":[{"href":"https:\/\/ipwithease.com\/wp-json\/wp\/v2\/posts\/5236","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ipwithease.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ipwithease.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ipwithease.com\/wp-json\/wp\/v2\/users\/782"}],"replies":[{"embeddable":true,"href":"https:\/\/ipwithease.com\/wp-json\/wp\/v2\/comments?post=5236"}],"version-history":[{"count":0,"href":"https:\/\/ipwithease.com\/wp-json\/wp\/v2\/posts\/5236\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ipwithease.com\/wp-json\/wp\/v2\/media\/23289"}],"wp:attachment":[{"href":"https:\/\/ipwithease.com\/wp-json\/wp\/v2\/media?parent=5236"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ipwithease.com\/wp-json\/wp\/v2\/categories?post=5236"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ipwithease.com\/wp-json\/wp\/v2\/tags?post=5236"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}