Service Discovery Gateway (mDNS Gateway)
Cisco's Service Discovery Gateway is an IOS component that implements the Zeroconf suite of technologies in IOS. Zeroconf is a widely used standard for plug-and-play service discovery, including Apple Bonjour® services. Zeroconf has been designed with the local network in mind and operates only in its local network. However, due to the huge success of the BYOD device in enterprises and educational institutions, the need to support Zeroconf enabled services beyond the boundaries of a local subnet has become top of mind.
Cisco's Service Discovery Gateway allows for controlled and secure access to services and devices across subnets. It listens to service announcements on all configured network segments and builds a cache of services and addresses. It proxies these requests to other segments and can also apply filters based on various service attributes. These filters can limit what services will be requested or advertised.
For detailed information about this feature, refer to Service Discovery Gateway Deployment Guide, Cisco IOS-XE Release 3.3.