Demarcation Point (Demarc)

The demarcation point (demarc) is the physical and contractual boundary between the carrier's network and the customer's premises wiring. Responsibility for fault-finding and equipment shifts at the demarc. In modern fibre deployments the ONT typically sits at the demarc; in copper it has historically been the network interface device on the building exterior.

Categories: Internet and RoutingIoT

Demarcation Point (Demarc) in context

Telecom networks depend on Internet-style routing (BGP, DNS, MPLS) for interconnect. Route hijacks and DNS abuse can degrade or intercept signaling, which is why RPKI and DNSSEC are now standard hardening for carrier networks.

Cellular IoT — NB-IoT, LTE-M and 5G mMTC — brings billions of devices with weak identities and long field lifetimes into operator networks, extending signaling attack surface at scale.

To place Demarcation Point (Demarc) in the wider telecom-security picture, review Endpoint, Network Slicing, PEI, SM-SR, 3G and 3GPP — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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