Cisco Catalyst 9800 Series Wireless Controller Software Configuration Guide, Cisco IOS XE 26.1.x

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Cisco Catalyst 9800 Series Wireless Controller Software Configuration Guide, Cisco IOS XE 26.1.x

Local area Bonjour for wireless FlexConnect mode

Updated: April 10, 2026

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Introduces core concepts of Local Area Bonjour in Wireless FlexConnect environments, explains restrictions and prerequisites, and compares mDNS gateway alternatives to facilitate effective service discovery and network design understanding.

Local area Bonjour for wireless FlexConnect mode is a network service feature that

  • introduces unicast mode function in Local Area Bonjour network domain

  • enables enhanced gateway function at the first hop of Wired and Wireless networks to communicate directly with any industry standard RFC 6762 compliant Multicast DNS (mDNS) end point in Layer 2 Unicast mode, and

  • provides service-peer mode expanding single-gateway to end-to-end service-routing with upstream SDG-Agent switch to enable unicast-mode, increased scale, performance and resiliency in the network.

Restrictions for local area Bonjour for wireless FlexConnect mode

In FlexConnect mode network deployments, the mDNS gateway and service-peer mode on the controller must not be configured and must be in disabled state.

Prerequisites for local area Bonjour for wireless FlexConnect mode

The Cisco Catalyst 9800 series controller must be successfully configured and operational before implementing Cisco Local Area Bonjour for FlexConnect mode wireless networks.

Here are the prerequisites to enable successful mDNS gateway solution for Wireless FlexConnect:

  • Ensure that the targeted Layer 2 Catalyst 9000 Series Ethernet switch is configured in service-peer role and running the required Cisco IOS-XE software version.

  • Ensure that the Catalyst 9000 Series Ethernet switch runs a valid Cisco DNA-Advantage license.

  • Ensure that the upstream distribution-layer Cisco Catalyst switch for Wired and FlexConnect Local Switching Wireless networks is configured in SDG-Agent mode and runs a valid Cisco DNA-Advantage license.

mDNS gateway alternatives for wireless FlexConnect mode

mDNS gateway alternatives for wireless FlexConnect mode are implementation methods that

  • address evolving business and technical requirements in Enterprise networks

  • enable service discovery and distribution in FlexConnect Local Switching based wireless networks, and

  • provide two distinct approaches based on the operating network environment.

Implementation methods

Based on the operating network environment, the mDNS gateway for FlexConnect mode wireless network can be implemented in one of the methods to address service discovery and distribution:

  • Switch Based mDNS Gateway—In Layer 2 access, the Cisco Catalyst 9000 series Ethernet switch must be implemented as mDNS gateway in Service-Peer role. The key benefits are:

    • Replaces flood-n-learn with the new enhanced Unicast-based mDNS communication with FlexConnect mode wireless users.

    • Eliminates mDNS flood with Unicast service-routing to LAN distribution. The Unicast service-routing between LAN distribution and Layer 2 access layer switches forms Local Area Bonjour domain to enable policy and location-based service discovery and distribution. The Unicast based service-routing over Layer 2 trunk eliminates mDNS flood-free and enables service-oriented wireless networks.

    • Eliminates the requirement to forward wired network traffic to wireless Access Points improving wireless scale, performance, and network reliability.

  • AP Based mDNS Gateway—The Cisco FlexConnect mode wireless access points can alternatively be implemented as mDNS gateway when connected to unsupported LAN access switch. In this method, the mDNS service discovery and distribution follows flood-n-learn mechanism over the Layer 2 wireless network. To implement AP based mDNS gateway, see the Multicast Domain Name System chapter.

Figure 1. mDNS gateway alternatives for FlexConnect mode
The diagram illustrates the mDNS gateway alternatives for Cisco FlexConnect mode, highlighting the AP-based mDNS gateway implementation and its flood-n-learn mechanism over the Layer 2 wireless network.

Local area Bonjour for wireless FlexConnect mode

Local area Bonjour for wireless FlexConnect mode is a mDNS gateway function that

  • supports various advancements for broad range of wireless networks with distributed zero-configuration services

  • enables distributed Bonjour gateway function at network edge through common unified Cisco IOS-XE operating system across Cisco Catalyst 9000 series LAN switches and Cisco Catalyst 9800 series controller

  • provides end-to-end Wide Area Bonjour service-routing for service-oriented enterprise networks with intuitive user-experience.

mDNS gateway modes

The Cisco Catalyst 9000 series switches in the Layer 2 access layer and Layer 3 distribution layer must be configured in specific mDNS gateway modes to enable Unicast-based mDNS service-routing between wired and FlexConnect Local Switching mode wireless users within the same Layer 2 network block:

  • Service-Peer - The Layer 2 access switch connecting wireless access point in FlexConnect Local Switching mode must be configured with mDNS gateway in Service-Peer mode. Each Layer 2 access switch provides mDNS gateway function between locally attached wired and FlexConnect mode wireless users. The Unicast-based mDNS service discovery and distribution within same or different VLANs is supported with bi-directional mDNS policies on single Layer 2 access switch.

  • SDG Agent - The mDNS flood-n-learn based method in Layer 2 network is replaced with simple Unicast based service-routing between Layer 2 access switch in Service-Peer mode and upstream distribution-layer in mDNS gateway SDG Agent mode. The Unicast based mDNS service-routing eliminates mDNS flood over Layer 2 trunk ports providing increased bandwidth, enhanced security, location-based services, and flood control management in wired and FlexConnect wireless network.

Controller mDNS gateway function architecture

This figure illustrates how the controller connected to wireless access points support mDNS gateway function to wireless users in FlexConnect Local Switching mode.

Figure 2. Cisco Catalyst 9800 series controller local area Bonjour for wireless - FlexConnect mode
The architecture of the Cisco Catalyst 9800 series controller demonstrates how it enables mDNS gateway functionality for wireless users through access points in FlexConnect Local Switching mode.