Cisco Cisco 5508 Wireless Controller 기술 참조

Chromecast is a digital media player developed by Google. The device, a HDMI dongle, plays 
audio/video content on a high-definition screen by directly streaming it via Wi-Fi from the Internet or a 
local network. Users select the media to play by using Chromecast enabled mobile/Web applications, or 
through a feature called “tab casting” that can mirror most Google Chrome browser content running on 
the device (MAC OSX and Windows).

Chromecast uses a simple multicast protocol for Discovery And Launch that enables users to mirror their 
devices on a second screen. 

The Chromecast devices operate on DIAL protocol. The DIAL Service Discovery enables a client to 
discover DIAL Server (Chromecast) on its local network, and obtain access to those services. This is 
achieved by using a new search target within the SSDP defined by uPNP.

The clients that wishes to discover Chromecast servers send a request over UDP to IP address 
239.255.255.250 and UDP port number 1900. See 

 for more 

information.

The multicast address used by the Chromecast discovery packets has a TTL (Time To Live) set to 1. 
Routers cannot use multicast routing to redirect traffic across L2 subnets because this results in only link 
local discovery of Chromecast, which might not be ideal for larger networks. 

This document provides information on deploying Chromecast over large networks with single, as well 
as multiple VLANs.

1. (Service Discovery Request)

1. (Response with IP address of service)

352546

Unicast Response

239.255.255.250

352547

239.255.255.250

VLAN Y

VLAN X

VLAN X

Chromecast Multicast
discovery can’t be Routed

CAPWAP Tunnel