Wireless Access

Hello,

This morning I ran into a strange issue with an iPad application and our Brother Printer (QL-710W).  The printer was not receiving print requests from the app.  I turned off Drop Broadcast and Unknown Multicast temporarily to see if there were any packets being dropped, and found:

01:17:32.891198 IP 10.14.100.10.5353 > 224.0.0.251.5353: 0 [5q] [5n] ANY (QU)? BRN008092DB3B7D.local. ANY (QU)? Brother QL-710W._pdl-datastream._tcp.local. ANY (QU)? Brother QL-710W._printer._tcp.local. ANY (QU)? Brother QL-710W._ipp._tcp.local. ANY (QU)?
01:17:33.149539 IP 10.14.100.10.5353 > 224.0.0.251.5353: 0 [5q] [5n] ANY (QM)? BRN008092DB3B7D.local. ANY (QM)? Brother QL-710W._pdl-datastream._tcp.local. ANY (QM)? Brother QL-710W._printer._tcp.local. ANY (QM)? Brother QL-710W._ipp._tcp.local. ANY (QM)?
01:17:33.401330 IP 10.14.100.10.5353 > 224.0.0.251.5353: 0 [5q] [5n] ANY (QM)? BRN008092DB3B7D.local. ANY (QM)? Brother QL-710W._pdl-datastream._tcp.local. ANY (QM)? Brother QL-710W._printer._tcp.local. ANY (QM)? Brother QL-710W._ipp._tcp.local. ANY (QM)?
01:17:33.661375 IP 10.14.100.10.5353 > 224.0.0.251.5353: 0*- [0q] 11/0/0 (Cache flush) A 10.14.100.10, (Cache flush) PTR BRN008092DB3B7D.local., (Cache flush) SRV BRN008092DB3B7D.local.:9100 0 0, (Cache flush) TXT "txtvers=1" "qtotal=1" "pdl=application/o
01:17:33.665537 IP 10.14.100.10.5353 > 224.0.0.251.5353: 0*- [0q] 8/0/0 (Cache flush) TXT "txtvers=1" "qtotal=1" "pdl=application/octet-stream,image/urf" "rp=ipp/print" "note=" "ty=Brother QL-710W" "product=(Brother QL-710W)" "adminurl=http://BRN008092DB3
01:17:33.697456 IP 10.14.100.10.138 > 255.255.255.255.138: NBT UDP PACKET(138)
01:17:33.698949 IP 10.14.100.10.137 > 255.255.255.255.137: NBT UDP PACKET(137): REGISTRATION; REQUEST; BROADCAST
01:17:33.906882 IP 10.14.100.10.137 > 255.255.255.255.137: NBT UDP PACKET(137): REGISTRATION; REQUEST; BROADCAST
01:17:34.160992 IP 10.14.100.10.137 > 255.255.255.255.137: NBT UDP PACKET(137): REGISTRATION; REQUEST; BROADCAST
01:17:34.683404 IP 10.14.100.10.5353 > 224.0.0.251.5353: 0*- [0q] 11/0/0 (Cache flush) A 10.14.100.10, (Cache flush) PTR BRN008092DB3B7D.local., (Cache flush) SRV BRN008092DB3B7D.local.:9100 0 0, (Cache flush) TXT "txtvers=1" "qtotal=1" "pdl=application/o
01:17:34.684101 IP 10.14.100.10.5353 > 224.0.0.251.5353: 0*- [0q] 8/0/0 (Cache flush) TXT "txtvers=1" "qtotal=1" "pdl=application/octet-stream,image/urf" "rp=ipp/print" "note=" "ty=Brother QL-710W" "product=(Brother QL-710W)" "adminurl=http://BRN008092DB3
01:17:36.724482 IP 10.14.100.10.5353 > 224.0.0.251.5353: 0*- [0q] 11/0/0 (Cache flush) A 10.14.100.10, (Cache flush) PTR BRN008092DB3B7D.local., (Cache flush) SRV BRN008092DB3B7D.local.:9100 0 0, (Cache flush) TXT "txtvers=1" "qtotal=1" "pdl=application/o
01:17:36.724912 IP 10.14.100.10.5353 > 224.0.0.251.5353: 0*- [0q] 8/0/0 (Cache flush) TXT "txtvers=1" "qtotal=1" "pdl=application/octet-stream,image/urf" "rp=ipp/print" "note=" "ty=Brother QL-710W" "product=(Brother QL-710W)" "adminurl=http://BRN008092DB3
01:17:39.568874 IP 10.14.100.10 > 224.0.0.252: igmp v2 report 224.0.0.252
01:17:40.803394 IP 10.14.100.10.5353 > 224.0.0.251.5353: 0*- [0q] 11/0/0 (Cache flush) A 10.14.100.10, (Cache flush) PTR BRN008092DB3B7D.local., (Cache flush) SRV BRN008092DB3B7D.local.:9100 0 0, (Cache flush) TXT "txtvers=1" "qtotal=1" "pdl=application/o
01:17:40.805711 IP 10.14.100.10.5353 > 224.0.0.251.5353: 0*- [0q] 8/0/0 (Cache flush) TXT "txtvers=1" "qtotal=1" "pdl=application/octet-stream,image/urf" "rp=ipp/print" "note=" "ty=Brother QL-710W" "product=(Brother QL-710W)" "adminurl=http://BRN008092DB3
01:17:42.223673 IP 10.14.100.10 > 224.0.0.251: igmp v2 report 224.0.0.251

Where 10.14.100.10 is the printer.  It appears that it is trying to using IGMPv2, and various ._tcp.local. strings which may not be defined in our AirGroup setup.  I am looking for some help in whitelisting the above multicast packets to ensure that we can re-enable Drop Broadcast and Unknown Multicast.

It looks as if AirPlay has some of these included, ie. _printer._tcp and _ipp._tcp.  Do I need to specifically call out the pre-pended Brother Printer information to let it pass, or?

The real answer is that you need to understand what protocol the App uses to print (Airprint, Maybe) and enable that in Airgroup services and make sure that is also enabled on your brother printer.  ON the ipad, most apps should use iPrint, so enable that in the Airgroup services and enable that in the printer as well.

You could run yourself in circles trying to enable a custom protocol (ipp) for every app/printer pair, instead of using a standard one like airprint that is already defined on the platform and printer already.  If that does not work, you will need to define a "printer" service in Airgroup that has the strings you see advertised, and enable it, so that your app can "see" the printer and hope the printer responds.

It looks like the multicast may have been dropped due to BCMC optimization being enabled.  On another controller with a similar WLAN, BCMC optimization was disabled while Drop Broadcast and Unknown Multicast was enabled.  This worked fine and the multicasts noted above were being propagated out as expected.