Enterprise Campus Switches 4.0.1 is not compatible with versions 3.x and below. Both switches in the MC-LAG pair must be upgraded at the same time.

Traffic through the MC-LAG pair is interrupted from the start of the upgrade until both peers have booted into 4.x and re-synchronized, which will take up to 10 minutes. Size the maintenance window accordingly.

This release adds support for ECS-Core and redesigns MC-LAG to deliver enterprise-grade stability with a unified control plane for spanning tree, MAC synchronization, and multicast state across peers.

We recommend using the latest version of UniFi Network.

Improvements

• Added MAC move protection to disable ports when the same MAC address is learned on multiple ports.
• Added MAC address table limits and usage reporting for addresses learned from MC-LAG peers.
• Added auto-negotiation support for 40 Gbps ports.
• Added the hostname to DHCP requests to support DNS registration.
• Added support file generation from UniFi Network.
• Added a notification when an MC-LAG pair loses its peer connection.
• Added spanning tree support across MC-LAG pairs, allowing both peers to operate as a single bridge.
• Improved spanning tree path selection, convergence, and loop protection across MC-LAG peers.
• Improved MC-LAG recovery after a reboot by waiting for peer synchronization before forwarding traffic.
• Improved topology change handling during MC-LAG failover.
• Improved IGMP Snooping and multicast forwarding across MC-LAG pairs.
• Improved handling of unknown and link-local multicast traffic.
• Improved diagnostics during high CPU usage.
• Improved MAC address synchronization between MC-LAG peers.
• Improved CPU protection under heavy traffic workloads.
• Increased the maximum number of LAGs to match the port count.

Bugfixes

• Fixed multiple issues affecting MC-LAG peer stability, synchronization, and recovery after failover or reboot.
• Fixed issues where MC-LAG peer links could report incorrect states or forward traffic incorrectly.
• Fixed issues where MC-LAG target links could lose connectivity during peer reboots, link changes, or failover.
• Fixed traffic storms and high CPU usage that could occur when creating or recreating MC-LAG groups.
• Fixed incorrect MC-LAG active-peer selection after a reboot.
• Fixed an issue where the built-in touchscreen could incorrectly report a loop while an MC-LAG peer was synchronizing.
• Fixed multiple MAC address synchronization and learning issues across MC-LAG peers.
• Fixed stale MAC addresses remaining after topology, VLAN, or MC-LAG configuration changes.
• Fixed an issue where traffic could be dropped for several minutes after a MAC address moved between MC-LAG peers.
• Fixed multiple network loop scenarios in single-tier and multi-tier MC-LAG deployments.
• Fixed multiple Spanning Tree path selection and convergence issues across MC-LAG peers.
• Fixed issues where ports could remain incorrectly blocked or forwarding after topology changes.
• Fixed multiple BPDU Guard and STP Edge Port configuration issues.
• Fixed repeated Spanning Tree topology changes and unnecessary MAC address table flushes.
• Fixed multiple IGMP Snooping issues affecting multicast forwarding across MC-LAG peers.
• Fixed multicast discovery and audio reliability across MC-LAG pairs.
• Fixed multicast traffic stopping or flooding after link and topology changes.
• Fixed multicast group membership synchronization and expiration across MC-LAG peers.
• Fixed multiple multicast router port and IGMP Querier state issues.
• Fixed IGMP Snooping failing to start in large deployments with 50 or more MC-LAG targets.
• Fixed DHCP Snooping dropping packets under heavy traffic, which could prevent clients from obtaining an IP address.
• Fixed DHCP Snooping state and reliability issues after VLAN configuration changes.
• Fixed multiple DHCP Guard issues affecting trusted server detection and rule application.
• Fixed DHCP Relay interruptions during MC-LAG and VLAN configuration changes.
• Fixed delayed DHCP Relay startup that could delay client address assignment after boot.
• Fixed issues where management DHCP or static IP configuration could fail to apply correctly.
• Fixed multiple SFP28 and QSFP module detection and compatibility issues.
• Fixed 25 Gbps links failing when FEC was disabled.
• Fixed 40 Gbps AOC detection and link speed reporting.
• Fixed 100 Gbps PSM4, LR4, and third-party bidirectional optic connectivity issues.
• Fixed 10 Gbps links flapping during transceiver detection.
• Fixed ports failing to establish links when module speed detection did not match the configuration.
• Fixed unnecessary port interruptions when applying configuration changes that did not modify speed or FEC settings.
• Fixed ports remaining error-disabled after the triggering condition was resolved.
• Fixed delayed port link-state reporting and incorrect flow control status.
• Fixed an issue where removing one port could interrupt traffic on other ports.
• Fixed an issue where routing could stop when processing a large number of neighbor updates.
• Fixed multiple MAC address table learning, aging, and reporting issues.

This is the first release for the ECS-Core.

Enterprise Campus Switch Aggregation 3.0.8 is focused on improving MC-LAG stability, multicast correctness, and predictable failover behavior in production environments.

This includes significant enhancements in synchronization, control-plane reliability, and system resiliency under load, along with a broad set of fixes addressing real-world deployment scenarios.

Further enhancements will continue to refine convergence performance and scalability in upcoming releases.

Deployment Guidelines

MC-LAG topology

• MC-LAG relies on automatic mrouter port election; manual configuration is not required.
• During MC-LAG failover events, brief convergence intervals may be observed depending on topology scale and traffic patterns.
• In large-scale deployments or during high-rate MAC movement, synchronization and convergence timing may vary based on system load.

IGMP / Multicast behavior

• When performing VLAN router role changes, temporarily disabling IGMP Snooping ensures consistent state transitions.
• Untagged multicast clients connected to ECS Aggregation ports may receive tagged group-specific queries; ensure client compatibility.
• Multicast traffic is not forwarded over the MC-LAG peer link and should be considered in network design.

Improvements

Platform & System

• Added support for DHCP Option 12 (hostname) in DHCP client communication.
• Improved 25G SFP compatibility with FEC-none auto-detection support.
• Improved database performance and reliability.
• Improved detection time for port state changes.
• Improved overall system stability and resource utilization.
• Expanded SFP transceiver compatibility with improved speed detection.

MC-LAG

• Improved MC-LAG session robustness and recovery behavior during failure scenarios.
• Improved MAC entry synchronization between MC-LAG peers.
• Improved MC-LAG peer-link stability under sustained high-load traffic conditions.
• Improved service stability in MC-LAG deployments.

STP

• Improved STP auto-edge port configuration stability.

Multicast / IGMP

• Improved IGMP querier election behavior in MC-LAG topologies.
• Improved resiliency of IGMP Snooping during topology and role changes.
• Improved synchronization of IGMP queries and reports across MC-LAG peers.
• Improved forwarding behavior for unknown multicast traffic toward mrouter ports.

Bugfixes

MC-LAG

• Fixed standby node going offline when changing peer-link members.
• Fixed FDB entries not synchronizing after MC-LAG daemon recovery.
• Fixed MC-LAG update failures during MAC creation operations.
• Fixed FDB synchronization issues when moving targets to orphan ports.
• Fixed high CPU utilization after disabling MC-LAG following prior enablement.
• Fixed memory leak during MC-LAG reconfiguration.
• Fixed stale VLAN entries persisting after MC-LAG removal.

STP

• Fixed STP port flapping and dual-speaker issues in certain topologies.
• Fixed STP state not being properly restored when modifying LAG membership.
• Fixed incorrect reporting of down ports as blocked by STP.
• Fixed STP errors when deleting an interface during configuration changes.
• Fixed incorrect STP port cost assignment for LAGs.
• Fixed unintended MAC learning from STP, LACP, and LLDP frames.
• Fixed admin-edge configuration not being cleaned up when removing an MC-LAG target.

Multicast / IGMP

• Fixed multicast router port desynchronization.
• Fixed multicast synchronization instability in MC-LAG environments at scale.
• Fixed unexpected multicast forwarding or dropping during reconvergence.
• Fixed multicast static entries not updating when VLAN membership changes.
• Fixed IGMP queries received on STP-blocked ports being incorrectly processed.
• Fixed incorrect mrouter port designation on STP-blocked ports.
• Fixed excessive IGMP report traffic on mrouter ports during blocked states.
• Fixed improper IGMP state cleanup when removing MC-LAG targets.
• Fixed non-RFC-compliant handling of group-specific IGMP queries.
• Fixed forwarding issues with reserved multicast traffic.
• Fixed multicast traffic interruption on group leave events across ports.

VLAN / L2 / Forwarding

• Fixed VLAN removal failure when multicast entries existed.
• Fixed MAC table synchronization issues when creating or deleting L3 networks.

DHCP / Security

• Fixed DHCP snooping packet pool exhaustion under heavy traffic.
• Fixed DHCP guarding behavior inconsistencies.
• Fixed DHCP snooping forwarding behavior when guard rules are enabled.
• Fixed the DHCP Relay service failure to start after reboot.

Stability / Traffic

• Fixed traffic storm during LAG member reconfiguration.
• Fixed buffer size validation issues impacting isolation rule creation.

Enterprise Campus Switch Aggregation 3.0.2 includes the improvements and bugfixes listed below.

Improvements

• Improved SFP speed detection on LAG ports.
• Improved SFP speed detection to enable faster link establishment.
• Improved firmware update stability.
• Improved overall configuration time.
• Improved CPU usage efficiency in topologies with a high MAC address count.

Bugfixes

• Fixed an issue where unknown multicast traffic was incorrectly forwarded to all VLAN members.
• Fixed MAC table synchronization issues in MC-LAG topologies.
• Fixed an issue where FDB entries could not be removed during MC-LAG configuration removal.
• Fixed a crash in the MC-LAG sync daemon when the peer switch disconnected.
• Fixed an issue preventing MC-LAG peer role switchover when the active peer went down.
• Fixed issues with clearing MAC table entries in MC-LAG topologies.
• Fixed a traffic storm issue triggered by the MC-LAG Target Device link configuration.
• Fixed port flapping when manual speed settings were applied to MC-LAG member ports.
• Fixed incorrect VLAN membership assignments for LAG member ports.
• Fixed inconsistent port negotiation configurations when using manual speed settings.
• Fixed port configuration errors during LAG configuration removal.
• Fixed invalid port state and speed reporting when operational status transitioned to "up."
• Fixed empty syslog entries caused by log rotation failures.
• Fixed an issue where SNMP data was not updated after VLAN removal.
• Fixed an issue where IGMP Snooping did not function correctly in MC-LAG topologies.
• Fixed an issue where Dante subscriptions were not processed correctly.

Enterprise Campus Switch Aggregation 3.0.0 includes the improvements and bugfixes listed below.

Improvements

• Added support for the IGMP Snooping options, Forward Unknown Multicast Traffic to Multicast Router Ports, and Control Flood Known Protocols.
• Improved link-up reliability for 40G/100G optics and DACs.

Bugfixes

• Fixed MAC syncing, peer stability, failover behavior, and crash conditions in MC-LAG environments.
• Fixed multicast traffic drop issues and improved compatibility with VRRP and unknown multicast scenarios.
• Fixed STP misbehavior (e.g., false port blocking) especially in redundant link or MC-LAG topologies.
• Fixed memory leaks and system crashes under load.

Enterprise Campus Switch Aggregation 2.1.19 includes the improvements and bugfixes listed below.

Improvements

• Improved device stability
• Improved link stability.
• Improved DHCP, STP, and SNMP stability.
• Improved DHCP Snooping performance.
• Improved DHCP and IGMP Snooping resiliency.
• Improved the uplink port reporting resiliency.
• Improved the L3 routing resiliency in an MC-LAG environment.

Bugfixes

• Fixed an issue where a Target Device could lose network connectivity when an MC-LAG member was restarted.
• Fixed an issue where restricted MAC didn't work correctly.
• Fixed the inability to SSH into the switch in rare cases.
• Fixed network loops when removing MC-LAG configurations.
• Fixed an issue where DHCP packets were incorrectly forwarded.
• Fixed an issue where IGMP Snooping Querier election doesn't work correctly.
• Fixed inconsistent MAC address of L3 networks.
• Fixed missing default route when configuring a static IP.
• Fixed memory leaks caused by DHCP Snooping and Link Detection.
• Fixed an issue where an incorrect default route was added after adding a new L3 Network.

This is the initial release for the ECS-Aggregation.