Odd Wired/Wireless Behavior Difference with Cisco Switch and Airplay (Bonjour) Device

Question

Summary

On a network (Cisco 2960E) with many Apple products, when I connect a computer via hard ethernet it cannot see Airplay devices (Airport Express) that it can see when connected via WiFi (WiFi devices are RUCKUS not Airport). In the hard line state, Bonjour Browser shows Apple and non-Apple services, but not the Airport Expresses.

Details

I have a Cisco Router (1941-sec) and Switch and Ruckus WiFi APs (7372) and Controller. The Switch has PoE for the APs and a handful of security cameras. These devices provide the backbone for my LAN. I'm not running VLAN, yet; every device is currently on the same subnet (10.10.10.XXX).

The AirPort Express devices (4) are present solely as Airplay points for music. Their phone jacks are piped into a multizone amplifier and to be used to send music from various Airplay music sources. Importantly, their WiFi is off and they are hardwired into the switch, picking up their IP addresses via DHCP (server runs on the Router).

When my computer is on WiFi and attached to the Ruckus APs, it can see the Airport Expresses. However, when my computer starts out hardwired (to the switch) only, it cannot see the AEs. If I temporarily turn on the WiFi and then turn it off, the computer sees the AEs and remembers them until sleep or reboot.

My assumption is that the Bonjour requests aren't making it from the computer to the AEs through the Switch, although I don't know why. Presumably, there's something the Ruckus APs are doing which puts their ports in a different state and encourages the packets to flow between the AEs and the APs. Something that my computer is not doing.

• Is there a way I can track, log or debug this?
• What can I do to test the Ruckus ports and compare them to the AE and Computer ports?
• Can I modify the AE or computer ports to improve this situation?
• Is there some global state for the Switch (or the Router) that I've missed?

I'm happy to provide more details (configuration files, etc.) if this would help. Also, I'm definitely new to all of this. I've got a reasonable understanding of how all of this stuff works, but I'm really just crawling along. I'm aware that Bonjour has problems across networks and there are bridges available, etc., that solve those problems. Please note, we are not in that situation as there is only one Class C network that everything sits on.

Answer 1

Andrew,

Bonjour relies on IP Multicast, so there are two possible issues:

1. The router (the switch appears to be acting as a router) is not configured to forward multicast traffic between the wired and wireless networks. If you enable multicast, be sure to enable igmp snooping on the switch as well, or you will be flooding the multicast traffic out all of the wired switch ports in that network.

2. A lot of enterprise wireless Access Points are configured by default to not transmit multicast traffic out to the air because it can consume valuable airtime and degrade the performance of the wireless network. It is possible to enable multicast if needed, but be aware multicast traffic is transmitted at the lowest data rate the wireless network is configured to support. Some enterprise AP's can be configured to optimize Multicast traffic by converting it to Unicast, check your documentation.

Even then it still might not work. Apple never designed Airplay to work across different subnets. However, it still may be possible to get it to work. Most enterprise wireless vendors have "special" support for Bonjour (or it's official name: Multicast Domain Name Service - MDNS). I believe Ruckus does have support for this, again you will have to consult your documentation.

-Neil

Answer 2

I don't know what I did to resolve this problem. I recall configuring Ruckus and the Cisco switch with cleaner VLAN settings. I never needed to bonjour to work across VLANs, so that wasn't the issue. There was some tricky Ruckus setting work required because of how their system handles the default VLAN when the ruckus access point initializes with DHCP and its IP address is not on one of the WLANs it supports.

@RonMaupin suggested I answer my own question to prevent it popping up on the unanswered question list. I hope this is sufficient and meets community standards.