Google Ad Manager allows for outbound inventory sharing, which occurs when an Ad Manager publisher receives ad requests, and must apply rules to delegate fulfilment of a percentage of such requests to a partner ad server.
Inbound inventory sharing occurs when a partner ad server receives the initial ad requests, and then delegates fulfilment of a percentage of such ad requests to a Google Ad Manager customer.
Both stream-based and impression-based inventory sharing are supported by Ad Manager for outbound sharing.
Stream-based inventory sharing
Ad Manager allows your host network to allocate a percentage of video inventory to a partner ad server for sharing on a per-request basis. For video on demand, requests are made and ads are allocated on a per-stream basis. For live stream, requests are made and ads are allocated on a per-break basis.
How ads are selected with stream-based inventory sharingWhen an ad request is received for all ads in a stream of video on demand content with a key name for a specific partner assignment, Ad Manager references the assignment and uses the specified percentage to perform a weighted decision.
For example, if a 10% share is set, then on each request there is a 10% chance that Ad Manager will provide all of the inventory in the stream to a partner, while there is a 90% chance that Ad Manager will select ads from the host Ad Manager network to fill all of the ads in the stream.
A partner assignment can be configured to share inventory with either another Ad Manager network or with FreeWheel. The data shared with a partner on the ad request is controlled by hardcoding certain ad tag values or placing dynamic macros to be populated in the ad request. The request to the partner ad server is executed from the Ad Manager server.
Ad Manager can optionally insert fallback ads, when the partner ad server has not filled all of the available inventory. Ad selection occurs per the following:
- Host selection: Ads for the host network are selected, even in cases where all inventory is shared.
- Partner selection: If a partner assignment is eligible and active based on the specified percentage, a request is made to the partner's ad server.
- Fallback selection: Ads returned from a partner ad server are considered "selected" for the ad response. Positions not filled by a partner are filled by the originally-selected host ads.
Both partner and host ads appear in the VAST or VMAP response. Partner ads maintain all of the VAST‑standard tracking URLs from the partner ad server. Ad Manager tracking URLs are added for Ad Manager reporting purposes. Partner and host ads are therefore mixed in ad responses.
Set up a stream-based inventory share
To configure a stream-based inventory share, you'll need to add a partner as an Ad Manager company, which allows you to configure an assignment that represents a specific sharing agreement. Stream-based assignments allow for a share percentage and a key name, which should be set as an ad tag parameter in cases where it should be applied.
For stream-based sharing, only one assignment can be applied on an ad request.
Impression-based inventory sharing
Ad Manager allows your host network to allocate a percentage of video inventory to a partner ad server for outbound sharing on a per-ad-slot basis. Pacing is based on a target percentage of host network ad impressions filled to partner network ad impressions filled.
How ads are selected with impression-based inventory sharingLogic applied to impression-based inventory sharing differs slightly from stream-based sharing.
Impressions are tracked separately for partner and host ads, with the ratio of partner to host ads in a 7-day rolling window, compared to the percentage target. A "partner fill multiplier" is used to adjust the number of ad slots allocated per break. This dynamic multiplier is determined by the discrepancy between the actual partner impression percentage and the target partner impression percentage.
Ad selection occurs per the following:
- Host selection: Ads for the host network are selected for all ad slots in a stream or ad break.
- Share determination: Based on the number of ad slots and the number of selected host ads, the number of ad slots offered to the partner are determined based on the target percentage and partner fill multiplier.
- Partner allocation: Based on the number of ad slots to be shared, specific slots in a break are designated for the partner. This occurs in reverse priority order, with slots unfilled by the host allocated first, and then any remaining slots filled starting with those occupied by the lowest value selected host ads.
- Partner selection: A request is made to the partner ad server for all of the ad slots allocated.
- Fallback selection: Ads that the partner ad server has returned are considered "selected" for the ad response. If a partner has not filled all ad slots, then the host ads originally selected are shown in those positions.
The selection process for impression-based sharing ensures the following:
- The partner is always offered a fair share of ad slots that, based on their fill rate, should allow them to meet the desired impression percentage.
- If a partner has a very low fill rate, regardless of the number of ad slots allocated to the partner, host ad serving appears uninterrupted. If no partner ads are returned, the break is filled with the same host ads that would have served had the partner allocation been zero.
- A rolling window is used to allow for the percent of ad slots offered to the partner to increase when perpetually low fill rate occurs in an effort to meet the contracted percentage. This can be seen using the "Total ad requests" metric, broken down by host, partner, and fallback.
Set up an impression-based inventory share
To configure a impression-based inventory share, you'll need to add a partner as an Ad Manager company, which allows you to configure an assignment that represents a specific sharing agreement. Impression-based assignments allow for a share percentage and a key name, which should be set as an ad tag parameter in cases where it should be applied.
For impression-based sharing, only one assignment can be applied on an ad request.
Control inventory shares with video ad rules
You can use video ad rules to control the eligibility of specific positions in a stream or break for inventory sharing. Specific positions, such as bumper or house ads designated to appear in the front or back of a pod, can be excluded from the requirement to share with a partner. For impression-based inventory sharing, these slots are not counted toward the share percentage.
Provide ad exclusions to partner ad servers
When you share inventory with a partner ad server, Ad Manager can pass ad categories, for content exclusions (for example, "do not serve alcohol ads on children's content") or competitive exclusions (for example, "Pepsi and Coke are in the 'beverage' category: if Pepsi serves in an ad break, do not serve Coke in the same ad break").
If your Ad Manager host network shares inventory with another Ad Manager network, a list of applicable ad category IDs are passed, for both content and competitive exclusions. For competitive exclusions, ad category IDs can be passed to enforce rules at the break or stream level, based on the rules relevant to the selected ads.
If your Ad Manager host network shares inventory with a third-party ad server, Ad Manager uses a map of proprietary ad category taxonomy to IAB Content Taxonomy. Passing a list of category exclusions in this manner is standardized in VAST 4.1. Partner ad servers should pass custom targeting values to themselves to negatively target the values.
The category of ads returned by a partner cannot currently be determined for fallback ads, so partner ad exclusions are not guaranteed in this case. Partner ad servers must use Ad Manager data.
