Internet Service Providers Industry Terminology

Acceptable Use Policy (AUP)

The set of rules an ISP publishes to define what customers may and may not do on the network (e.g., spam, abuse, hosting servers on residential lines). It governs enforcement actions like throttling or termination for violations.

Review the AUP before running a home server; We updated the AUP to clarify P2P allowances; Repeated DMCA notices are handled under the AUP

Access Network (Last-Mile)

The portion of the network that connects a customer’s premises to the ISP’s aggregation point, using fiber, copper, coax, or wireless. It’s often the most capital-intensive and operationally complex segment.

The outage is isolated to the last-mile segment; We’re overbuilding the last mile with fiber; The CLEC leases last-mile access from the incumbent

ARPU (Average Revenue Per User)

A core financial metric tracking the average monthly revenue generated per subscriber, used to evaluate pricing strategy and growth.

ARPU rose after the speed-tier migration; Bundling TV and voice increased ARPU; We target a 5% ARPU uplift this year

ASN (Autonomous System Number)

A unique identifier assigned to a network (autonomous system) that participates in BGP routing on the public Internet.

We received our ASN allocation from ARIN; Announce those prefixes under our new ASN; Peering requires exchanging ASNs and routing policies

Backbone Network

The high-capacity core that interconnects an ISP’s PoPs, regions, and external peers/transit, typically using long-haul fiber and high-speed routers.

Traffic is rerouted on the backbone ring; We’re upgrading the backbone to 400G; Backbone congestion caused elevated latency

Backhaul

Connectivity that transports aggregated traffic from access nodes (e.g., OLTs, CMTS, wireless towers) to the core/PoP. It can be fiber or microwave.

Microwave backhaul augments remote sites; We need more backhaul to the new neighborhood node; Backhaul saturation is throttling peak speeds

Bandwidth

The maximum data transfer capacity of a link, typically measured in Mbps or Gbps; distinct from throughput (actual measured rate).

This plan includes 1 Gbps bandwidth; Backbone links are 100 Gbps each; Customer perceives low bandwidth when Wi‑Fi is the bottleneck

BGP (Border Gateway Protocol)

The interdomain routing protocol used between autonomous systems to exchange reachability and path information; basis for peering and transit.

Set local-pref for that transit route; Communities mark DoS-mitigated prefixes; We’ll deprefer that path using MED

Bitstream Access

A wholesale model where a retailer uses an incumbent’s access network while managing IP services, without controlling the physical loop.

We sell over the incumbent’s bitstream product; Bitstream and LLU have different margins; Regulatory changes impacted bitstream pricing

CAPEX (Capital Expenditure)

Funds spent to acquire or upgrade long-lived assets like fiber, ducts, OLTs, CMTS, and routers; central to build-out economics and ROI models.

CAPEX per home passed dropped 20%; We’re deferring CAPEX until permits clear; The board approved multi-year fiber CAPEX

Carrier-Grade NAT (CGNAT)

Large-scale NAT (NAT44) operated by ISPs to share scarce IPv4 addresses among many subscribers, often impacting inbound connectivity and logging complexity.

Port forwarding won’t work behind CGNAT; We log CGNAT translations for abuse handling; Upsell a static public IP to bypass CGNAT

CDN (Content Delivery Network)

A distributed caching network that brings content closer to users to reduce latency and transit costs; ISPs often host CDN nodes or peer locally.

Cache-fill traffic dominates this link; We onboarded a Netflix/Open Connect node; CDN offload reduced transit by 40%

Churn

The rate at which customers disconnect service over a period; a key retention and growth metric.

Monthly churn fell after improving install SLAs; Price increases risk higher churn; Win-back campaigns target high-propensity churners

Co-location (Colo)

Leasing space, power, and cross-connects in a data center to house ISP routers, servers, and caches.

We added a rack at the downtown colo; Power density limits the colo expansion; Order a cross-connect to the IXP fabric

CPE (Customer Premises Equipment)

Equipment at the customer site, such as modems, ONTs, routers, Wi‑Fi gateways, and set-top boxes; may be ISP-managed.

Swap the CPE for a Wi‑Fi 6 gateway; The ONT light levels look marginal; Zero-touch CPE provisioning cuts truck rolls

Cross-Connect

A dedicated physical connection inside a data center between two parties (e.g., ISP to transit, CDN, or IXP).

Provision a single-mode cross-connect to the carrier; Cross-connect fees impact colo OPEX; We’ll add a second cross-connect for redundancy

Dark Fiber

Unlit fiber strands leased or owned by an ISP, over which the ISP places its own optics to create wavelengths or Ethernet links.

Lease dark fiber on an IRU basis; Light the dark fiber with 100G DWDM; Dark fiber enables low-latency metro rings

DDoS (Distributed Denial of Service)

An attack that floods networks or services with traffic to exhaust bandwidth or resources; ISPs mitigate with scrubbing, ACLs, and blackholing.

Auto-null route via RTBH was triggered; Scrubbing centers cleaned the attack traffic; Enable BGP FlowSpec for rapid mitigation

DHCP (Dynamic Host Configuration Protocol)

Protocol that automatically assigns IP addresses and related parameters to devices (DHCPv4/DHCPv6) on IPoE or behind CPE.

DHCP lease times were shortened; Option 82 tags help locate the subscriber; The modem isn’t getting a DHCP offer

DIA (Dedicated Internet Access)

Enterprise-grade, symmetric, uncontended Internet service with strict SLAs and guaranteed bandwidth (CIR).

The bank needs 1 Gbps DIA with 4-hour MTTR; DIA pricing is per-Mbps with 95th percentile billing; We’ll deliver DIA on a diverse path

DOCSIS

Cable broadband standard for HFC networks (e.g., 3.1, 4.0) that defines PHY/MAC layers and supports high downstream (OFDM) and evolving upstream capacities.

Upgrade to DOCSIS 3.1 OFDMA upstreams; Node splits relieved DOCSIS congestion; DOCSIS 4.0 targets multi-gig symmetrical

DPI (Deep Packet Inspection)

Technology that inspects packet payloads and headers for classification, security, or policy enforcement; can raise privacy/regulatory concerns.

Use DPI for lawful intercept compliance; DPI enables application-aware QoS; Regulators scrutinize DPI-based throttling

Edge Data Center

A small, regional data center close to end users that hosts caches, compute, and network gear to reduce latency and backhaul usage.

Deploy an edge DC with local IX access; Move gaming caches to the edge; Edge sites cut latency by 15 ms

Fair Use Policy (FUP)

A policy that tempers ‘unlimited’ plans by setting thresholds for heavy usage or behaviors likely to impair others, often triggering deprioritization.

After 1 TB, FUP applies during peak hours; We revised FUP language for transparency; FUP violations now receive alerts first

Fixed Wireless Access (FWA)

Broadband delivered over radio links (e.g., 5G, LTE, licensed microwave, or unlicensed bands), typically for last-mile access.

5G FWA expanded rural coverage; Align dishes for better FWA signal quality; Licensed spectrum improved FWA reliability

FTTx (FTTH/FTTN/FTTC)

Umbrella term for fiber deployments to various demarcation points: home (FTTH), node (FTTN), or curb/cabinet (FTTC).

Shift from FTTN to FTTH over the next 3 years; FTTx CAPEX per passing is trending down; Marketing will badge the area as FTTH-ready

Gigabit Service Tier

A retail plan advertised around 1 Gbps speeds; real-world throughput can vary due to Wi‑Fi, overhead, and network conditions.

Gig tier uptake is driving ARPU growth; Provision 1.2 Gbps to cover overhead; We’re launching a 2-gig tier next quarter

GPON/XGS-PON

Passive optical network standards: GPON (~2.5G/1.25G) and XGS-PON (10G symmetric), using OLTs/ONUs on shared fiber.

Migrate splitters to support XGS-PON; OLT line cards support both GPON and XGS; Split ratio adjustments reduce contention

Headend

The central hub in a cable/HFC network hosting CMTS/CCAP, QAMs, and video processing; increasingly distributed via Remote PHY/DAA.

Move to a distributed headend architecture; New CCAP deployed at the headend; Add redundancy to the headend power

HFC (Hybrid Fiber-Coax)

Access architecture combining fiber-fed nodes and coaxial distribution to homes, widely used by cable ISPs.

Perform a node split on the HFC plant; Upstream noise is impacting HFC performance; DAA helps modernize HFC networks

Internet Exchange Point (IXP)

A shared Layer-2 fabric where networks interconnect and exchange traffic, typically via route servers, enabling low-latency, cost-effective peering.

Join the local IXP to offload transit; Turn up sessions on the route servers; IXP ports are now available at 100G

IP Transit

A paid service providing global Internet reachability via an upstream AS; billed by committed rates or 95th percentile.

Add a second transit provider for resilience; We negotiated better transit pricing; Transit usage dropped after new peering

IPv4 Exhaustion

The global scarcity of IPv4 addresses leading to CGNAT, address markets, and accelerated IPv6 adoption.

We acquired a /19 on the secondary market; CGNAT bridges the IPv4 shortage; Policy changes tightened IPv4 transfers

IPv6

The 128-bit Internet addressing protocol designed to replace IPv4, enabling vast address space and simplified routing; commonly deployed dual-stack.

Enable IPv6 on all CPE; IPv6-only with NAT64 is on the roadmap; Adoption improved after adding v6 to Wi‑Fi

Jitter

The variation in packet latency over time; high jitter impairs real-time applications like voice and gaming.

QoS tweaks reduced jitter to <10 ms; VoIP MOS scores fell due to jitter; Bufferbloat can manifest as jitter spikes

KPI (Key Performance Indicator)

Quantitative metrics used to track business and operational performance, e.g., ARPU, churn, installation interval, latency, NPS.

Churn and ARPU are our headline KPIs; The NOC dashboard surfaces network KPIs; We tied bonuses to install-interval KPIs

Latency

The time it takes for data to travel between endpoints, measured as one-way or round-trip time; core determinant of perceived responsiveness.

Latency to the game server is 25 ms; Edge caching cut latency significantly; Backhaul congestion increased latency

LLU (Local Loop Unbundling)

A regulatory framework that allows competitors to lease the incumbent’s copper pair to deliver services directly, controlling the DSLAM and service.

LLU enabled faster retail competition; Shift from LLU to fiber bitstream is underway; Margins differ between LLU and wholesaled fiber

MPLS (Multiprotocol Label Switching)

A label-switching technology used in ISP cores to engineer traffic and deliver L2/L3 VPNs; being complemented by Segment Routing.

Deploy MPLS-TE for congestion hotspots; Migrate LDP to SR-MPLS over time; MPLS underpins our business VPN services

MTTR (Mean Time To Repair)

The average time required to restore service after a fault; often an SLA metric with financial penalties.

Our DIA MTTR target is 4 hours; Proactive spares reduced MTTR; Automated triage cuts MTTR on fiber breaks

Net Neutrality

The principle that ISPs should not block, throttle, or prioritize traffic for consideration, subject to reasonable network management and legal obligations.

Zero-rating raises neutrality questions; We disclosed traffic management under the rules; Policy shifts could change neutrality enforcement

NOC (Network Operations Center)

The 24/7 team and facility that monitors, troubleshoots, and coordinates maintenance for the ISP network.

The NOC opened a Sev-1 ticket; Follow the NOC playbook for route leaks; NOC escalated to field ops for a fiber cut

OPEX (Operating Expenditure)

Ongoing costs to operate the network and business, such as transit, power, leases, maintenance, and staffing.

Transit contracts are a major OPEX line; Energy efficiency helps lower OPEX; Automation reduces provisioning OPEX

OTT (Over-The-Top)

Services (video, voice, apps) delivered via the Internet without the ISP controlling the content or end-to-end quality.

OTT video is driving peak traffic; VoIP OTT competes with voice bundles; Bundle strategies counter OTT churn

Packet Loss

The fraction of packets that are dropped or never arrive; a critical SLA and quality metric that harms throughput and real-time media.

Packet loss exceeded SLA thresholds; Upstream errors caused loss bursts; FEC helped mask light packet loss

Peering

Direct interconnection between networks to exchange traffic, either settlement-free or paid; can be public (IXP) or private.

We signed a bilateral peering with the CDN; Move heavy flows to private peering; Peering policy requires traffic balance

Point of Presence (PoP)

A location where an ISP houses network gear to serve a region and interconnect (e.g., to IXPs, CDNs, and carriers).

Open a new PoP in the west metro; PoP diversity improves resilience; That building’s meet-me room hosts our PoP

Provisioning

The workflows and systems (OSS/BSS) that activate and configure services and customer equipment, ideally via automation/zero-touch.

Zero-touch provisioning speeds installs; Provision the ONT and assign VLANs; APIs connect BSS to provisioning

QoS (Quality of Service)

Techniques to prioritize, shape, and police traffic to meet performance targets for latency-sensitive or high-priority flows.

Mark VoIP with DSCP EF; Subscriber QoS tiers enforce speed plans; Queue tuning improved video start times

Service Level Agreement (SLA)

Contractual commitments for performance and support (e.g., uptime, latency, jitter, packet loss, MTTR), with remedies for non-compliance.

Our DIA SLA guarantees 99.99% uptime; Latency/packet loss are SLA-backed metrics; Credits applied after we missed the SLA