Describes how to configure local and wide area Bonjour domains to enable service discovery and communication across different network segments and geographic locations.
How to configure multicast DNS mode for LAN and wired networks
This section provides information about how to configure Local Area Bonjour in multicast DNS mode.
Enable mDNS gateway on the device
Enable mDNS gateway functionality on the device to allow multicast DNS service discovery across network segments.
mDNS gateway enables devices to discover and communicate with services across different network segments using multicast DNS protocols.
Before you begin
Follow these steps to configure mDNS on the device:
Procedure
| 1. | enable Example:Enables privileged EXEC mode. Enter your password, if prompted. |
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| 2. | configure terminal Example:Enters global configuration mode. |
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| 3. | mdns-sd gateway Example:Enables mDNS on the device and enters mDNS gateway configuration mode. Enter the following commands in mDNS gateway configuration mode to enable the respective functionalities:
The following CLIs are effective only in service-peer mode:
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| 4. | exit Example:Exits mDNS gateway configuration mode. |
mDNS gateway is now enabled on the device and ready to facilitate multicast DNS service discovery across network segments.
Create custom service definition (GUI)
Create a custom service definition to define specific mDNS services that can be discovered and used within your network environment.
Custom service definitions allow you to specify particular service types that devices on your network can advertise and discover through mDNS (multicast Domain Name System). This is useful for managing which services are available for discovery in your network infrastructure.
Before you begin
Follow these steps to create custom service definition using GUI:
Procedure
| 1. | Choose . |
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| 2. | Click Add. |
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| 3. | Enter the Service Definition Name and Description. |
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| 4. | Enter the Service Type and click the + icon. |
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| 5. | Click Apply to Device. |
The custom service definition is created and applied to the device. The new service definition will be available for use in mDNS service policies and can be discovered by devices on the network.
Create custom service definition
Create a custom service definition to provide an admin-friendly name to one or more mDNS service types or PTR Resource Record Names.
Service definition is a construct that provides an admin friendly name to one or more mDNS service types or PTR Resource Record Name. By default, a few built-in service definitions are already predefined and available for admin to use. In addition to built-in service definitions, admin can also define custom service definitions.
Procedure
| 1. | enable Example:Enables privileged EXEC mode. Enter your password, if prompted. |
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| 2. | configure terminal Example:Enters global configuration mode. |
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| 3. | mdns-sd service-definition service-definition-name Example:Configures mDNS service definition.
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| 4. | service-type string Example:Configures mDNS service type. |
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| 5. | Repeat step 4 to configure more than one service type in the custom service definition. |
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| 6. | exit Example:Exit mDNS service definition configuration mode. |
The custom service definition is created and added to the primary service list, making it available for use in mDNS configurations.
Create a service list (GUI)
Create service lists to control mDNS service discovery by specifying which services are allowed or denied in the network.
Service lists provide a mechanism to filter mDNS services based on service types and message types, helping you manage service discovery traffic in your network.
Procedure
| 1. | Choose . |
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| 2. | Click Add. |
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| 3. | Enter the Service List Name and choose the direction from the Direction drop-down list. |
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| 4. | Click Add Service. |
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| 5. | Choose the service from the Available Services drop-down list and the message type from the Message Type drop-down list. |
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| 6. | Click Save. |
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| 7. | Click Apply to Device. |
The service list is created and applied to the device, enabling mDNS service filtering based on your configured parameters.
Create service list
Create an mDNS service list to organize service definitions and control service discovery traffic.
mDNS service list is a collection of service definitions. Use service lists to manage which services are allowed IN or OUT of specific network segments.
Before you begin
Follow these steps to create a service list:
Procedure
| 1. | enable Example:Enables privileged EXEC mode. Enter your password, if prompted. |
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| 2. | configure terminal Example:Enters global configuration mode. |
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| 3. | mdns-sd service-list service-list-name {IN | OUT} Example:Configures mDNS service list. |
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| 4. | match service-definition-name [message-type {any | announcement | query}] Example:Matches the service to the message type. Here, service-definition-name refers to the names of services, such as, airplay, airserver, airtunes, and so on.
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| 5. | exit Example:Exits mDNS service list configuration mode. |
The mDNS service list is created and configured with the specified service definitions and message types.
Create service policy (GUI)
Create a service policy to manage mDNS services and control service discovery between network segments.
Service policies define how mDNS services are handled across different network locations by specifying input and output service lists.
Procedure
| 1. | Choose . |
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| 2. | Click Add. |
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| 3. | Enter the Service Policy Name. |
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| 4. | Choose the service list input from the Service List Input drop-down list. |
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| 5. | Choose the service list output from the Service List Output drop-down list. |
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| 6. | Choose the location from the Location drop-down list. |
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| 7. | Click Apply to Device. |
The service policy is created and applied to the device. The mDNS service discovery is now controlled according to the configured policy parameters.
Create service policy
Create a service policy to specify allowed Bonjour service announcements or queries that should be processed IN ingress or egress directions.
A Service Policy that is applied to an interface specifies the allowed Bonjour service announcements or the queries of specific service types that should be processed, IN ingress direction or egress direction or both. For this, the service policy specifies two service-lists, one each for ingress and egress directions. IN the Local Area Bonjour domain, the same service policy can be attached to one or more Bonjour client VLANs; however, different VLANs may have different service policies.
Before you begin
Follow these steps to configure service policy with service lists:
Procedure
| 1. | enable Example:Enables privileged EXEC mode. Enter your password, if prompted. |
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| 2. | configure terminal Example:Enters global configuration mode. |
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| 3. | mdns-sd service-policy service-policy-name Example:Configures mDNS service policy. |
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| 4. | service-list service-list-name {IN | OUT} Example:Configures service lists for IN and OUT directions. |
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| 5. | exit Example:Exits mDNS service policy configuration mode. |
The mDNS service policy is created and configured with service lists for ingress and egress directions.
Associate service policy to an interface
Associate a service policy to an interface to enable mDNS (multicast DNS) functionality and govern Bonjour announcements and queries.
mDNS configuration on the device requires associating service policies to interfaces to control Bonjour service behavior on VLANs.
Before you begin
Follow these steps to configure mDNS on the device:
Procedure
| 1. | enable Example:Enables privileged EXEC mode. Enter your password, if prompted. |
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| 2. | configure terminal Example:Enters global configuration mode. |
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| 3. | interface interface-name Example:Enters interface mDNS configuration mode and enables interface configuration. |
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| 4. | mdns-sd gateway Example:Configures mDNS gateway on the interface. Enter these commands in the interface mDNS gateway configuration mode to enable the respective functionalities:
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| 5. | exit Example:Exits mDNS gateway configuration mode. |
The mDNS gateway is configured on the interface with the service policy attached. The interface can now process Bonjour announcements and queries according to the configured policies.
Local area Bonjour in multicast DNS mode for wireless networks
Local area Bonjour in multicast DNS mode is a service discovery framework that relies on mDNS messages transmitted over UDP port 5353 to facilitate communication between network endpoints.
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Operates using service announcements and queries sent to mDNS IPv4 address 224.0.0.251 and IPv6 address FF02::FB.
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Functions as a Layer 2 protocol, requiring clients to reside within the same Layer 2 domain for service discovery.
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Requires transparent mDNS transmission support from intermediate WLCs to bridge wireless endpoints and SDG Agents.
Wireless Network Configuration Requirements
To enable mDNS communication between wireless endpoints and a Cisco Catalyst switch acting as an SDG Agent, perform the following configuration steps:
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Disable mDNS Snooping on Cisco AireOS based WLCs.
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Enable the mDNS Gateway feature on Cisco Catalyst 9800 series WLCs.
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Set the AP Multicast Mode to Multicast.
The following figure illustrates the prerequisite configuration for wireless networks to enable communication between SDG-Agent switches and wireless endpoints.
The configuration of local area Bonjour on a switch that acts as the SDG Agent in a wireless network involves the same set of procedures that are used to configure local area Bonjour on a switch that acts as the SDG Agent in a wired network.
The Bonjour protocol operates on service announcements and queries. Each query or advertisement is sent to the mDNS IPv4 address 224.0.0.251 and IPv6 address FF02::FB. The mDNS messages are carried over well-known industry standard UDP port 5353, over both Layer 3 transport types.
The Layer 2 address used by the Bonjour protocol is link-local multicast address and therefore it’s only forwarded to the same Layer 2 network. As multicast DNS (mDNS) is limited to a Layer 2 domain, for a client to discover a service, it has to be a part of the same Layer 2 domain. This isn’t always possible in a large-scale deployment or enterprise.
To enable mDNS communication between Wireless endpoints and Cisco Catalyst switch that acts as an SDG Agent, the intermediate WLC must transparently allow the network to transmit and receive mDNS messages.
Hence, for a Multicast DNS Mode Wireless network deployment, disable the mDNS Snooping on Cisco AireOS based WLC and enable mDNS Gateway feature on Cisco Catalyst 9800 series WLC and set the AP Multicast Mode to Multicast.
The Cisco WLC and Access Points by default prevent the forwarding of Layer 2 or Layer 3 Multicast frames between Wireless and Wired network infrastructure. The forwarding is supported with stateful capabilities enabled using AP Multicast. The network administrator must globally enable Multicast and configure a unique Multicast Group to advertise in the network. This multicast group is only required for Cisco Access Points to enable Multicast over Multicast (MCMC) capabilities across the LAN network. The Bonjour solution doesn’t require any Multicast requirements on Wireless Client VLAN; thus, it’s optional and applicable only for other Layer 3 Multicast applications.
The core network must be configured with appropriate Multicast routing to allow the Access Points to join WLC Multicast Group. The Multicast configuration must be enabled on Cisco WLC management VLAN and on the Cisco Access Points of their respective distribution layer switch.
Associate service policy with wireless profile policy
This task allows you to override the default mDNS service policy with a custom service policy of your choice.
A default mDNS service policy is already attached once the wireless profile policy is created. Use this procedure to override the default mDNS service policy with any of your service policy.
Before you begin
Follow these steps to associate service policy with wireless profile policy:
Procedure
| 1. | enable Example:Enables privileged EXEC mode. Enter your password, if prompted. |
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| 2. | configure terminal Example:Enters global configuration mode. |
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| 3. | wireless profile policy profile-policy-name Example:Configures wireless profile policy. |
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| 4. | mdns-sd service-policy custom-mdns-service-policy Example:Associates an mDNS service policy with the wireless profile policy. The default mDNS service policy name is default-mdns-service-policy . |
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| 5. | exit Example:Exits wireless profile policy configuration mode. |
The custom mDNS service policy is now associated with the wireless profile policy, overriding the default service policy.
Configure wide area Bonjour domain
The Wide Area Bonjour domain configuration specifies the parameters of the controller, that is the Wide Area Bonjour Application running on Cisco Catalyst Center, as well as the service types that need to be exported to it from the SDG Agent. Configuring Wide Area Bonjour Domain involves creating service-lists and service policy similar to those created in Local Area Bonjour configuration; however, only egress policy from SDG Agent to controller is applicable.
Associate service policy with the controller in wide area Bonjour domain
This task enables the association of service policies with controllers in Wide Area Bonjour domains to manage service discovery and distribution across the network.
In Wide Area Bonjour, the service policy is configured globally and does not get associated with a VLAN as in the case of Local Area Bonjour.
Before you begin
Follow these steps to configure service policy globally:
Procedure
| 1. | enable Example:Enables privileged EXEC mode. Enter your password, if prompted. |
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| 2. | configure terminal Example:Enters global configuration mode. |
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| 3. | service-export mdns-sd controller controller name Example:Specifies a name for the controller and enters service-export mode |
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| 4. | controller-address ipv4-address Example:Specifies the controller address. |
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| 5. | controller-port port-number Example:Specifies the port number on which the controller is listening. |
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| 6. | controller-source-interface interface-name Example:Specifies the source-interface for the controller. |
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| 7. | controller-service-policy service-policy-name OUT Example:Specifies the service policy to be used by the controller.
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| 8. | exit Example:Exits controller service export configuration mode. |
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| 9. | mdns-sd gateway Example:Enters mDNS gateway configuration mode. |
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| 10. | ingress-client query-suppression enable Example:Enables ingress query suppression for better scale and performance. |
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| 11. | exit Example:Exits mDNS gateway configuration mode. |
The service policy is successfully associated with the controller in the Wide Area Bonjour domain, enabling global service discovery management and ingress query suppression.
Configure HSRP-aware mDNS service-routing on SDG
Configure hot standby router protocol-aware (HSRP-aware) mDNS service-routing on SDG using the referenced configuration guides for Catalyst switch platforms.
For information, see these guides:
Configure HSRP-aware mDNS service-routing on service-peer
Configure HSRP-aware mDNS service-routing on service-peer to enable multicast DNS gateway functionality with hot standby router protocol awareness.
Use this procedure when you need to configure mDNS gateway in service-peer mode with HSRP awareness to provide redundancy and high availability for mDNS services.
Before you begin
Follow these steps to configure hot standby router protocol-aware mDNS service-routing on service-peer:
Procedure
| 1. | configure terminal Example:Enters global configuration mode. |
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| 2. | mdns-sd gateway Example:Enables mDNS on the device and enters mDNS gateway configuration mode. |
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| 3. | mode service-peer Example:Enables mDNS gateway in service-peer mode. |
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| 4. | source-interface vlan vlan-interface-number Example:Configures source interface to communicate between SDG Agent and service-peer.
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| 5. | SDG-agent IP-address Example:Configures SDG agent IPv4 or IPv6 address.
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| 6. | end Example:Exits server group configuration mode and enters privileged EXEC mode. |
The device is configured with HSRP-aware mDNS service-routing on service-peer mode, enabling multicast DNS gateway functionality with hot standby router protocol support.