Host 2 queries for printers

The following procedure depicts a service process for mDNS queries for a wireless printer in the form of an example.

Procedure
  1. Host 2 sends an mDNS query for printers.
  2. There is no inbound filter in VLAN 2 of Switch 3 therefore it receives the query.
  3. Switch 3 checks the outbound filter in VLAN 2. As there is no specific outbound filter the default action is permit all.
  4. Switch 3 floods the query in VLAN 2 (except the source port.)
  5. Switch 1 receives the query and check the inbound filters. Permit for the instance name, Host 2, allows the packet on VLAN 2.
  6. Switch 1 checks the outbound filter for VLAN 2. As there is no specific filter and global filter is permit all, it will flood the packet in VLAN 2 (except the source port.)
  7. Switch 1 checks the reflection status. Reflection is enabled on VLAN 2 and VLAN 3. Since VLAN 2 is an incoming VLAN, it will not pass the reflection on VLAN 2.
  8. Switch 1 checks the outbound filters on VLAN 3. There is no rule to deny Host two query and the global filter is set to permit all so it will forward the packet to VLAN 3.
  9. Switch 2 receives the service and checks for any inbound and outbound filters in VLAN 3.
  10. There is no specific inbound and outbound filter in VLAN 3 therefore it will flood the query in VLAN 3 (except the source port.)
  11. Reflection is not enabled in Switch 2 therefore it will not pass any further reflection.
  12. Wireless printer 2 responses to the query and switch 2 does not have any inbound and outbound filters therefore it will flood the response to VLAN 3 (except the source port.)
  13. Switch 1 receives the packet as there are no inbound filters in VLAN 3. VLAN 3 has an outbound filter set to deny wireless printer service. The service will not flood VLAN 3.
  14. Switch 1 checks the reflection status which is enabled in VLAN 2 and 3. Since the incoming VLAN is 3, the packet will not forward to VLAN 3.
  15. Switch 1 checks the outbound filter in VLAN 2. As there is no specific filter, it will forward the response to VLAN 2.
  16. Switch 3 receives the response on VLAN 2 as there is no inbound filter to deny this service.
  17. Switch 3 does not have any outbound filters in VLAN 2, so it will flood the response in VLAN 2 (except the source port.)
  18. Host 2 receives the Wireless Printer 2 service response.