ULL Solution release notes

GA with allowlist: ULL Solution is available only to approved exchange operators and their exchange participants. If you are an approved exchange participant, contact [e-mail] 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.

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August 12, 2026

Announcement

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

ULL Solution is generally available (GA) 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.

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.

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.

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.

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.

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.

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.

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.
• 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.
• 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.

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.

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 and the Cloud Multicast documentation.