Cloud egress glossary for FinOps readers

C — CHR / cross-AZ / cross-region

Cache hit ratio (CHR)

Share of requests or bytes served from cache; drives origin egress estimates. CDN origin fill estimator · Vercel Blob vs R2 CHR levers origin fill: client GB × (1 − CHR) ≈ miss bytes — measure byte-CHR and request-CHR separately. Sensitivity twins on the estimating and multi-CDN spokes show how a 70%→40% CHR swing changes origin GB without inventing a new path class. Also: Multi-CDN origin fill · CloudFront vs Cloudflare · Mode C.

Cross-AZ (cross-zone) transfer

Data movement between availability zones in a region; common HA tax. Cross-AZ vs cross-region · ELB cross-zone Keep instance InterZone apart from ELB cross-zone; chatty multi-AZ stacks can dominate below cross-region rates. The deepened cross-AZ spoke now separates fixed-shape HA chatter from ELB cross-zone siblings so CE InterZone lines stay honest. Also: NAT vs IGW · Cost Explorer decoder · ?path=cross-az.

Cross-region transfer

Data movement between regions; usually priced above cross-AZ. When the bytes are S3 bucket→bucket replication, use S3 CRR — not only this generic meter. Cross-AZ vs cross-region · S3 CRR egress · AWS vs GCP egress Multi-cloud sync usually bills the source egress path; keep rates Unknown until verified. Also: S3 vs R2.

D — Direct Connect

Direct Connect / Interconnect

Dedicated or partner hybrid interconnect (AWS Direct Connect; sibling vocabulary: GCP Interconnect, Azure ExpressRoute) — model port hours plus private transfer GB separately from Internet DT-out. Direct Connect vs Internet · Cost Explorer decoder Port hours and private transfer GB are separate lines from Internet DT-out — not interchangeable SKUs. Residual NAT after a DX cutover still stacks the triple-charge pattern for leftover Internet SaaS — keep that sibling explicit on the DX spoke worked-estimate. Also: AWS egress path checklist · AWS vs GCP egress · Methodology.

E — Egress / ELB cross-zone

Egress / data transfer out

Bytes leaving a cloud provider boundary toward the Internet or another region/provider — metering varies by product. Egress vs ingress · S3 vs R2 · AWS vs GCP Object GET, CDN edge, NAT Internet DT-out, and replication are sibling path templates, not one “egress $/GB.” Decode opaque CE labels on the Cost Explorer decoder before Mode A arithmetic; multi-cloud shape compares live on AWS vs GCP egress. Also: AWS free-tier cliff · R2 vs B2 · Mode A.

ELB cross-zone data transfer

Bytes moved across availability zones by a load balancer when cross-zone load balancing is enabled — may differ from instance InterZone meters. ALB/NLB cross-zone · Cross-AZ vs cross-region Enabling cross-zone for even distribution is an HA choice with a transfer tax — measure before assuming free symmetry. Keep ELB GB off the EC2 InterZone line on the CE decoder; the deepened ELB spoke pairs on-vs-off twins with cross-AZ siblings. Also: AWS egress path checklist · Cross-AZ vs cross-region.

F — FinOps-lite / free-tier cliff

FinOps-lite

Lightweight cost education and estimators — not a full FinOps platform or committed-use broker. About PipeToll · Cloud egress calculator Path templates, Unknown badges, and Mode A/B/C — not a broker or savings guarantee; cite via methodology. Also: FAQ · Disclosures.

Free-tier cliff

Point where complimentary egress/bandwidth allotments end and list $/GB begins — model explicitly. AWS free-tier cliff · Multi-cloud free-tier cliffs Model the cliff remainder as its own line; cliffs ≠ R2 $0 marketing and ≠ S3 CRR. Pair the AWS cliff with the Azure & GCP cliffs matrix and the R2 vs B2 egress-friendly storage spoke when bills blur complimentary allotments with object GET. Also: S3 vs R2 · ?path=free-tier-cliff.

I — Ingress / IGW

Ingress

Bytes entering a provider; often free, but still verify processing or load-balancer charges. Egress vs ingress · NAT vs IGW “Ingress free” is not a blanket bill claim — processing, LB, or PrivateLink-style fees can still fire. Also: AWS egress path checklist.

Internet Gateway (IGW)

VPC component for public-subnet Internet routing without NAT processing fees. NAT vs Internet Gateway IGW removes NAT hourly/processing but Internet DT-out and free-tier cliffs still apply. Also: VPC endpoints vs NAT · AWS free-tier cliff.

M — Multi-CDN

Multi-CDN

Two or more CDNs in front of one origin; model CHR and origin fill per lane. Multi-CDN origin fill · CDN origin fill Model CHR and origin fill per lane — blended CHR hides a cold secondary; failover can spike origin GB. Pair with the estimating spoke CHR sensitivity twin and keep CRR / free-tier cliff meters off the origin-fill cell. Also: CloudFront vs Cloudflare · AWS free-tier cliff · Mode C.

N — NAT processing

NAT Gateway processing

Per-GB charge for traffic traversing a managed NAT — distinct from Internet egress. NAT vs Internet Gateway · Calculator Mode B (NAT) With hourly + Internet DT-out this is the triple-charge pattern; cross-AZ hairpins add a fourth meter. After a hybrid cutover, residual NAT still belongs on the DX vs Internet sibling — do not zero processing just because DX port hours appear. Also: VPC endpoints vs NAT · PrivateLink vs NAT.

O — Origin fill

Origin fill / origin egress

Bytes pulled from origin storage/compute when a CDN cache misses. CDN origin fill estimator · Calculator Mode C (origin) Client edge GB ≠ origin GB; estimate fill as client × (1 − CHR). Keep Mode A GET apart from Mode C fill. Multi-CDN lanes need per-lane CHR — see multi-CDN origin fill — so a cold secondary does not hide behind a blended ratio. Also: S3 direct vs CloudFront · CloudFront vs Cloudflare.

P — Path template / PrivateLink

Path template

PipeToll term: a normalized traffic shape (who→where→SKU) used before comparing $/GB. Compare hub · Methodology Name who→where→SKU before comparing $/GB so NAT processing is not blended with Internet DT-out or CRR with public GET. Use the compare hub Suggested path for an ordered walk, or jump by cluster when the meter family is already known — still existing spokes only. Also: AWS egress path checklist · Cost Explorer decoder · Calculator.

S — S3 CRR

S3 Cross-Region Replication (CRR)

Asynchronous copy of S3 objects to a destination bucket in another Region — inter-region replication meters and ops, not Internet GET egress and not Transfer Acceleration. S3 CRR egress · Transfer Acceleration · Cost Explorer decoder Durability/DR replication ≠ end-user downloads ≠ CDN origin fill — keep CRR off Mode A public-GET cells. When CE shows inter-region replication next to Internet GET, use the decoder + CRR spoke before the R2 vs B2 or S3 vs GCS matrices. Also: S3 vs R2 · Cross-AZ vs cross-region.

S3 Transfer Acceleration

Edge-accelerated transfers to/from S3 — distinct meter from standard Internet DT-out. Transfer Acceleration vs Internet Distinct from Internet DT-out and from S3 CRR; confirm which meter fired. Also: S3 vs R2 · ?path=s3-ta.

T — Triple-charge / Transfer Acceleration

Transit Gateway (TGW)

AWS hub for VPC and hybrid attachments — model attachment hours plus data-processing GB separately from peering and Internet DT-out. Peering vs Transit Gateway Attachment hours + processing GB stay separate from peering and Internet DT-out; TGW is transitive, peering is bilateral. Also: AWS egress path checklist · Cost Explorer decoder.

Triple-charge pattern

Educational stack of hourly + per-GB processing + Internet egress (classic NAT lesson). NAT vs Internet Gateway · Calculator Mode B (NAT) Cross-AZ hairpins to a shared NAT can add a fourth meter; endpoints may remove AWS-bound bytes but not true-Internet need. Hybrid interconnect cutovers still leave residual NAT for public SaaS — keep that stack on DX vs Internet and Mode B. Also: VPC endpoints vs NAT · PrivateLink vs NAT.

U — Unknown until verified

Unknown until verified

PipeToll label for rates not yet cited to a dated provider source — no invented numbers. Methodology No scorecrowns from Incomplete cells — paste $/GB only after a human cites a dated provider page. Deepened spokes still carry Unknown badges on sensitivity tables so worked estimates stay educational, not quotes. Also: Calculator · Cost Explorer decoder · Compare hub.

V — VPC endpoint

VPC endpoint (gateway / interface)

Private path to AWS services without NAT Internet hairpins — gateway (prefix) or interface/PrivateLink (ENI). Fees differ from NAT. VPC endpoints vs NAT · PrivateLink vs NAT egress · NAT vs IGW Gateway (prefix) vs interface/PrivateLink (ENI); per-AZ sprawl multiplies hours; endpoints do not cover arbitrary Internet SaaS. Also: Mode B (?path=privatelink-vs-nat).

VPC peering

Bilateral VPC-to-VPC link — model peering data-transfer GB and cross-AZ separately; no transitive routing through a peer. Peering vs Transit Gateway No transitive routing through a peer — use Transit Gateway for a hub; peering ≠ Internet DT-out. Also: Cross-AZ vs cross-region · AWS egress path checklist.