Cisco also plans to extend one of its existing technologies, called Network Based Application Recognition, to its wireless LAN firmware. For the first time, Cisco WLAN controllers will be able to dissect packets and compare them to a database of about 1,500 application signatures to identify a specific application — such as a video conference versus a Netflix video, or a Skype voice call — to be prioritized, blocked, or given bandwidth limits, for example.
Bonjour, originally called Rendezvous when introduced in the early 2000s, is Apples latest implementation of zero configuration networking or Zeroconf, which is a group of open Layer 2 protocols to automatically and quickly set up an IP network, without having to set up services such as Dynamic Host Configuration Protocol, DNS, and DNS Service Directory. (More background is online at a page maintained by Stuart Cheshire, Zeroconfs pioneer, who was later hired by Apple.)
And in simple home Wi-Fi networks, thats just what happens: Apple clients broadcast for services, the services identify themselves, and client and service simply connect, paving the way for specific Apple protocols like AirPrint for printers and AirPlay for sharing multimedia among Apple clients via an intervening Apple TV box
But the strengths of Bonjour become problematic in more complex networks, which now can have hundreds, thousands or tens of thousands of iPhones and iPads advertising for services, but unable to connect if theyre on separate subnets. And the discovery traffic can, according to some colleges and universities, sometimes hit 90% of the network load. The problems are pressing enough that last week a group of higher education IT managers finalized a petition to Apple, asking for a range of Bonjour, and related, changes to make the protocols better citizens on enterprise networks.
Cisco is the third WLAN vendor to address these issues with a Bonjour gateway.
On a Cisco WLAN, Apple clients will advertise for Bonjour services, just as they do now, says Chris Spain, vice president of product marketing for Ciscos wireless business unit. The Cisco access point then will tunnel those requests back to the WLAN controller, and match them with an inventory of available AirPrint printers, Apple TVs, iTunes libraries and the like on any subnet in the enterprise network. The controller identifies the user, matches the authenticated user with his or her access privileges and grants access to the requested Bonjour service or not, based on group policies.
So faculty but not students might have access to Apple TVs in specific rooms, or to certain AirPrint printers.
Ciscos Webcast promotional page puts it this way: With the Cisco Bonjour Gateway, available in a future software update, the wireless controller will answer device service queries in proxy of the server. Once the client gets a response it can connect via layer 3. Now file servers, printers, video devices, or any Bonjour server device can be accessed across subnetsmaking it easy for users to access the services they need.
Spain says Cisco is currently testing the gateway to find out how and to what degree it can reduce Bonjour discovery traffic. In effect, with the intervening controller, every Bonjour request-response appears to the client device as a local, single-network transaction. Because the controller acts as a proxy for other Bonjour services on other subnets, it can minimize broadcasts, at least in theory.
We think the gateway will reduce the total amount of Bonjour traffic over the network, says Spain.