--- title: Network Layer: Interface or Node Addresses « ipSpace.net... description: A deep dive into the historical and architectural question of whether network-layer addresses should belong to nodes or individual interfaces. IP assigns... canonical: https://daily.dev/posts/network-layer-interface-or-node-addresses-ipspace-net-blog-86ibm5cqb twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Network Layer: Interface or Node Addresses « ipSpace.net blog | daily.dev og:description: A deep dive into the historical and architectural question of whether network-layer addresses should belong to nodes or individual interfaces. IP assigns... og:url: https://daily.dev/posts/network-layer-interface-or-node-addresses-ipspace-net-blog-86ibm5cqb og:image: https://api.daily.dev/og/posts/86IbM5cqb.png og:image:alt: Network Layer: Interface or Node Addresses « ipSpace.net blog og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Network Layer: Interface or Node Addresses « ipSpace.net blog **[ipSpace.net Blog](https://daily.dev/sources/ipspace)** · 6 min read · 0 upvotes · 0 comments ## Summary A deep dive into the historical and architectural question of whether network-layer addresses should belong to nodes or individual interfaces. IP assigns addresses per interface (tied to subnets), while OSI CLNP assigns a single address per node regardless of interface count. The post traces why these two approaches emerged: CLNP grew from DEC and IBM environments where hosts acted as routers and node identity mattered most, while IP was designed as an internetworking protocol layered on top of an existing WAN (ARPANET's IMPs). The post sets up a series comparing the two models across neighbor discovery, routing, multi-homing, and scalability. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### Why does IP assign addresses to interfaces rather than to nodes? IP was designed as an internetworking protocol layered on top of an existing WAN built by BBN (ARPANET). In that network, hosts connected to Interface Message Processors (IMPs) via a single port, and the host's address was essentially its port number on the IMP. When Ethernet arrived and hosts gained multiple interfaces, per-interface addressing was already baked in, with each interface belonging to a subnet. _Engineers designing multi-homed systems or studying protocol history track these fundamentals on daily.dev._ ### What is the difference between how OSI CLNP and IP handle network layer addressing? OSI CLNP assigns a single network-layer address to the node itself, regardless of how many interfaces it has. Each interface still gets a unique data-link address (MAC or X.25), but there is only one CLNP address per node. IP, by contrast, assigns addresses per interface, with each interface belonging to a subnet prefix. IS-IS, still widely used today, inherits the CLNP node-level addressing model. _Networking engineers comparing routing protocol designs find protocol deep-dives like this on daily.dev._ ## Similar posts on daily.dev - [Computer Networks Explained: The Complete Guide](https://daily.dev/posts/computer-networks-explained-the-complete-guide-uozado4ud) · Medium · 0 upvotes · 0 comments --- Tags: [#networking](https://daily.dev/tags/networking) [View this post on daily.dev](https://daily.dev/posts/network-layer-interface-or-node-addresses-ipspace-net-blog-86ibm5cqb) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Network Layer: Interface or Node Addresses « ipSpace.net blog","url":"https://daily.dev/posts/network-layer-interface-or-node-addresses-ipspace-net-blog-86ibm5cqb","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/network-layer-interface-or-node-addresses-ipspace-net-blog-86ibm5cqb"},"datePublished":"2026-08-11T08:55:21.571Z","dateModified":"2026-08-11T09:04:04.811Z","description":"A deep dive into the historical and architectural question of whether network-layer addresses should belong to nodes or individual interfaces. 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In that network, hosts connected to Interface Message Processors (IMPs) via a single port, and the host's address was essentially its port number on the IMP. When Ethernet arrived and hosts gained multiple interfaces, per-interface addressing was already baked in, with each interface belonging to a subnet. Engineers designing multi-homed systems or studying protocol history track these fundamentals on daily.dev."}},{"@type":"Question","name":"What is the difference between how OSI CLNP and IP handle network layer addressing?","acceptedAnswer":{"@type":"Answer","text":"OSI CLNP assigns a single network-layer address to the node itself, regardless of how many interfaces it has. Each interface still gets a unique data-link address (MAC or X.25), but there is only one CLNP address per node. IP, by contrast, assigns addresses per interface, with each interface belonging to a subnet prefix. IS-IS, still widely used today, inherits the CLNP node-level addressing model. 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