Dual-homed design

As explained in Acing the CCNA Exam: Volume 2 Advanced Networking and Security

A dual-homed design is an internet connectivity arrangement with two connections to the same Internet service provider.

A dual-homed design connects a network to the same Internet service provider through two separate connections. If one connection fails, traffic can use the other, improving availability over a single-homed design. section 16.2.5

Common deployment choices differ in redundancy, cost, and complexity:

• A dual-router design gives each router one ISP connection and protects against a router hardware failure; one router can remain available if the other fails. section 16.2.5
• A single router can also terminate two connections, but this provides less hardware redundancy than using two routers. section 16.2.5
• Because both connections depend on one ISP, an ISP-wide problem can still interrupt service; multi-homed designs use multiple ISPs for greater resilience. section 16.2.5 section 16.4

Figure 16.12 internet connection designs. Single-homed = one connection to one ISP. Dual-homed = two connections to one ISP. Multi-homed = one connection to each of two (or more) ISPs. Dual multi-homed = two connections to each of two (or more) ISPs.

Compare single-homed, dual-homed, multi-homed, and dual multi-homed arrangements by connection count, ISP dependence, and redundancy. section 16.2.5

How Acing the CCNA Exam: Volume 2 Advanced Networking and Security covers it

How deep it goes

Defines connection options and failure boundaries but does not provide configuration commands or verification procedures.

Examples

Uses two routers with one connection each and a single router with two connections as alternative arrangements.

What you can do after

Evaluate Internet redundancy designs against link failure, router failure, ISP failure, cost, and complexity.

How it connects

Contrasts single-homed, multi-homed, and dual multi-homed designs through redundancy, ISP dependence, cost, and complexity.

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Related concepts

• single-homed designcontrasts with · A single-homed design is an internet connectivity arrangement with one connection to one Internet service provider.
• redundancyproduces · Redundancy is the presence of duplicate or overlapping information, components, or resources, whether intentional or unnecessary.
• multi-homed designcontrasts with · A multi-homed design connects a network to multiple internet service providers, typically with one connection to each provider.

This explainer was generated by Manning's knowledge graph from the text of Acing the CCNA Exam: Volume 2 Advanced Networking and Security. The section links point to the parts of the book it draws on.