Protocol boundaries and data handoff by segment
Purpose
This document explains the ad platform flow by segment, not just by role. The goal is to distinguish where strong industry standards exist, where platform-specific common models dominate, and which kinds of data are exchanged in each segment.
Key Takeaways
- Ad platforms do not run on a single protocol from start to finish.
- The
DSP ↔ SSP / Exchangesegment is the strongest standards-driven segment, centered on OpenRTB. - The
SSP ↔ Publisher SDK / Player / Tagsegment follows common industry patterns, but not one dominant universal protocol. - The
SDK / Player ↔ Measurement / Verificationsegment relies heavily on VAST tracking and OM SDK / OMID. - The
Advertiser · Agency ↔ DSPsegment is closer to campaign control than to runtime auctioning.
Big Picture
At a Glance
| Segment | Primary concern | Strong protocol | Representative data |
|---|---|---|---|
| Advertiser · Agency ↔ DSP | campaign setup, targeting, budget, creative operations | No dominant universal standard | campaign, line item, creative, audience, budget, goal |
| DSP ↔ SSP / Exchange | auctioning, bidding, pricing, creative handoff | OpenRTB | id, imp, site/app, device, user, source, regs, price, adm |
| SSP ↔ Publisher SDK / Player / Tag | ad request, ad response, creative / VAST delivery | No dominant universal standard, VAST is important in video | placement, app/site context, VAST URL/XML, markup, trackers |
| SDK / Player ↔ Measurement / Verification | impression, click, progress, viewability, verification | VAST Tracking, OM SDK / OMID | impression, click, quartile, AdVerifications, OM session |
Why this distinction matters
1. To avoid overstating OpenRTB
OpenRTB is extremely important, but it is strongest in the SSP ↔ DSP / Exchange auction segment. The segment where the publisher runtime requests an ad and later emits measurement signals depends on other protocols and runtime rules as well.
2. To separate data ownership
campaign budgetbelongs to the advertiser ↔ DSP control segment.imp,device, andregsbelong primarily to the bid request segment.adm, VAST URLs, and markup bridge the auction outcome into delivery.impression,click,quartile, andviewabilitybelong to the runtime event segment.
3. To make system design discussions more precise
Many recurring confusions come from mixing ad request with bid request, ad response with bid response, or imp with impression. Looking at the flow by segment makes the producer and owner of each data type much clearer.