If UPnP devices do not see each other, most likely there are two problems:
Multicasts are not forwarded
Simple Service Discovery Protocol (SSDP) uses multicast IPv4 address 126.96.36.199. The local switches must be able to forward such traffic. On a Cisco switch you run the following command to allow that:
no ip igmp snooping vlan 101
Firewall blocks UPnP traffic
Related ports: UDP-1900 and TCP-2869
In my mind universality and simplicity are mutually exclusive. I’m yet to find a system which is universal and simple to configure and use. Reliability and stability are assumed by default.
The simplicity of Apple devices is addictive. You add a new box and it gets automatically recognized. Everything just works like prescribed and defined by Apple. Then it’s a question of if this Procrustean bed fits you or not and if you are flexible enough to assume the offered model.
The idea of service/device discovery appeared in the late 90’s. For example, Sun’s Jini (1998) and UPnP (1999). It’s nice to have a standard to allow devices from different vendors work together, right? Sure, but here comes the reality. The Cisco interpretation of the Spanning Tree Protocol is different from the Foundry (now Brocade) one. If you place Cisco and Foundry switches/load balancers in one LAN, you may end up with a funny STP loop.
Continue reading “Universality vs Simplicity or PSAudio and The Bridge woes”