> [!NOTE]
> **GA with allowlist** : ULL Solution is available only to approved exchange operators and their exchange participants.
> If you are an approved exchange participant, contact [exchanges@google.com](mailto:exchanges@google.com) to request access.

This page documents production updates to Ultra Low Latency (ULL) Solution. Check this page for announcements about new or updated features, bug fixes, known issues, and deprecated functionality.
You can see the latest product updates for all of Google Cloud on the
[Google Cloud](https://docs.cloud.google.com/release-notes) page, browse and filter all release notes in the
[Google Cloud console](https://console.cloud.google.com/release-notes),
or programmatically access release notes in
[BigQuery](https://console.cloud.google.com/bigquery?p=bigquery-public-data&d=google_cloud_release_notes&t=release_notes&page=table).

## October 14, 2026

Feature U4S instances support [Hyperdisk Throughput](https://docs.cloud.google.com/compute/docs/disks/hd-types/hyperdisk-throughput)
(`hyperdisk-throughput`) block storage. For more information, see
[Supported disk types for U4S instances](https://docs.cloud.google.com/ull-solution/participants/u4-machines#u4s-disks).

## October 08, 2026

Feature You can filter mirrored traffic by the primary IP address ranges of the capture
point. For more information, see [Create a ULL Packet Mirroring collector filter
rule](https://docs.cloud.google.com/ull-solution/participants/packet-mirroring/set-up-packet-mirroring-ull#create-ull-pm-collector-filter-rule).

## October 05, 2026

Feature Information about ULL unicast packet loss is available in Flow Analyzer.
For more information, see
[Analyze traffic flows with Flow Analyzer](https://docs.cloud.google.com/ull-solution/participants/view-flow-logs#analyze-flows).

## September 30, 2026

Feature **Preview** : Ultra Low Latency (ULL) Packet
Mirroring is available for exchange participants. You can clone traffic from
your ULL VPC networks and forward it to collector instances for analysis without
affecting latency or performance. For more information, see [Packet Mirroring
for ULL VPC
networks](https://docs.cloud.google.com/ull-solution/participants/packet-mirroring/packet-mirroring-ull).

## August 12, 2026

Announcement **General Availability with allowlist**: Ultra Low Latency (ULL) Solution

[ULL Solution](https://docs.cloud.google.com/ull-solution/participants/configuration-overview) is generally
available ([GA](https://cloud.google.com/products#product-launch-stages))
with allowlist in private zones `us-south1-d` and `us-south1-e` for approved
exchange participants.

For more information about the services included in ULL Solution, see the
following:
Feature **ULL VPC networks** : ULL Virtual Private Cloud (VPC) networks provide support
for ultra-low latency unicast and multicast traffic for market trading
applications, respecting strict latency, jitter, and multicast variance targets. Connectivity
between exchange operators and participants is managed through Network
Connectivity Center (NCC), which uses a hub and spoke model. For more
information, see [About participant ULL VPC networks](https://docs.cloud.google.com/ull-solution/participants/participant-ull-network-profile).
Feature **Firewall for ULL VPC networks** : Firewall rules in regional network firewall
policies are supported for ULL VPC networks through the `ULL_POLICY` firewall
policy type. For more information, see
[Firewall for ULL VPC networks](https://docs.cloud.google.com/ull-solution/participants/firewall/overview).
Feature **Compute Engine U4 machine family** : U4 is Google Cloud's ULL
network-optimized machine family designed to support the core workloads of
financial exchange ecosystems. U4C bare metal instances run on 5th generation
(Emerald Rapids) Intel Xeon processors and provide ULL
connectivity for exchange participants. U4S virtual machine (VM) instances
run on 6th generation (Granite Rapids) Intel Xeon processors and
provide support for adjacent workloads. For more information, see
[U4 Ultra Low Latency (ULL) machine family](https://docs.cloud.google.com/ull-solution/participants/u4-machines).

Google Cloud provides public Red Hat Enterprise Linux (RHEL) and Rocky Linux operating
system (OS) images for use with U4 instances. These images support the required
functionality for ULL Solution. For more information, see
[Operating system support for U4 machine types](https://docs.cloud.google.com/ull-solution/participants/u4-machines#u4-os-images).
Feature **Guest networking and Onload** : You can use Onload, a high-performance
user-space network stack, to optimize the performance of trading
applications that run on U4 instances. Using Onload with ULL Solution includes
flow steering support for unicast and multicast traffic.
For procedures for using Onload on the supported public OS images,
including setup, busy polling configuration, and performance optimization,
see [Work with Onload](https://docs.cloud.google.com/ull-solution/participants/use-onload).
Feature **Time synchronization** : The Firefly protocol provides nanosecond-level time
synchronization for U4 instances, including both U4C bare metal instances and
U4S VM instances. You can configure accurate time for an instance by
synchronizing the system clock of the instance to the physical NIC clock of its
host server. Additionally, you can monitor the accuracy of this time
synchronization through Cloud Monitoring. For more information, see
[Configure accurate time for U4 Compute Engine instances](https://docs.cloud.google.com/ull-solution/participants/configure-time-sync).
Feature **ULL Multicast** : ULL Multicast provides a hardware-based multicast service for
applications with strict latency and multicast variance requirements. It relies on infrastructure directly in the physical network fabric to replicate and distribute traffic.
After ULL Multicast is configured, U4C instance network interfaces attached to
ULL VPC networks can join and leave multicast groups by using IGMPv2. For more
information, see the [ULL Multicast overview](https://docs.cloud.google.com/ull-solution/participants/multicast-overview).
Feature **Observability**: ULL Solution includes the following observability features:

- **VPC Flow Logs** : Provides visibility into bandwidth, network latency, network packet loss, and instance packet loss. For more information, see [VPC Flow Logs records for ULL traffic](https://docs.cloud.google.com/ull-solution/participants/view-flow-logs#ull-records).
- **Flow Analyzer** : All of the information in VPC Flow Logs records for ULL traffic is available in Flow Analyzer, except for ULL unicast packet loss. For more information, see [Analyze traffic flows with Flow Analyzer](https://docs.cloud.google.com/ull-solution/participants/view-flow-logs#analyze-flows).
- **Group membership event logs** : You can monitor multicast group membership events, such as IGMP join and leave requests. For more information, see [View group membership event logs for ULL Multicast](https://docs.cloud.google.com/ull-solution/participants/view-membership-logs).
Feature **Dual-zone design and maintenance schedule** : ULL Solution uses a dual-zone
design to help ensure that regular maintenance and testing can be performed
without interrupting market trading. The *production zone* is the active
environment for live trading. The *maintenance zone* is the inactive environment
for updates, repairs, and testing. Information about the maintenance schedule
is available through the Google Cloud API. For more information, see
[Maintenance in ULL Solution private zones](https://docs.cloud.google.com/ull-solution/participants/zone-maintenance).
Feature **Cloud Multicast in ULL Solution private zones** : Cloud Multicast is supported
for use in ULL Solution private zones, including with U4S instances and the
`nic0` (non-ULL) interface of U4C instances. Cloud Multicast is a multicast
service based on software-defined networking that uses multicast infrastructure
in a tenant project and network managed by Google to replicate and distribute
traffic. For more information, see
[Comparison of ULL Multicast and Cloud Multicast](https://docs.cloud.google.com/ull-solution/participants/multicast-overview#comparison) and the [Cloud Multicast](https://docs.cloud.google.com/vpc/docs/multicast/overview)
documentation.