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, transport and application delivery. Route hijacks and DNS abuse can degrade or intercept signaling as easily as any application-layer attack, 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, long field lifetimes and limited patchability into operator networks. The same signaling attacks that target smartphones (location tracking, denial of service, credential exfiltration) apply, often at greater scale.

To place Demarcation Point (Demarc) in the wider telecom-security picture, review Endpoint, Network Slicing, PEI, DMZ, Authorization and Last Mile.

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