No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>Search


To have a better experience, please upgrade your IE browser.


The Port Tag Is Set Incorrectly So That the Video Service Cannot Implement the Multicast Function

Publication Date:  2012-07-25 Views:  102 Downloads:  0

Issue Description

1. Networking: Video server ------OSN2500 (N2EFS0) - OSN2500 (N2EFS0) -------Gigabit switch -- Gigabit switch ------Video matrix-------Monitor/TV wall
2. The Ethernet leased line service is set for the transmission devices and the access attribute is set for external ports.
3. The objective of users is to transparently transfer the service of the video server, implement the multicast function on the Gigabit switch, and replicate the service to simultaneously display on the monitor and TV wall.
4. Symptom: The video service can be displayed on either the monitor or the TV wall, but cannot on both of them. 

Alarm Information


Handling Process

1. We first consider that the problem is not related to the transmission devices because the lease line service is configured. The transparent service transmission and multicast function are implemented on the switches, and therefore, we doubt that the configurations on the switches are incorrect. The multicast function can be implemented, however, after the transmission devices are not considered.
2. We query the customer whether multicast protocol frames contain VLANs. The customer verifies that multicast protocol frames contain VLANs indeed. After we guide the customer to change the attribute of external ports from access to hybrid, the video service can simultaneously be displayed on the monitor and TV wall.
3. Obviously, the switches fail to receive multicast protocol frames because the service contains no VLAN while multicast protocol frames contain VLAN. 

Root Cause

The multicast function cannot be implemented for some reason. 


1. If we say one service can normally be transferred through a port on the transmission device but another service cannot be transferred through the same port, we can easily locate the cause for the fault. As this problem involves the concepts such as video server and multicast, it seems to be very complicated. In fact, if we can find out the critical points, the problem is still very simple.
2. It is incorrect to say that the Ethernet leased line service implements only the transparent service transmission and the multicast protocol cannot be enabled for the service. In fact, if the board supports the multicast protocol, the multicast protocol can be enabled. The specific function can be understood as the service replication on the transmission device. In this example, service replication is implemented on the switches.