How can I implement QOS on Cisco 1721 routers with the MultiVOIP?You may use DIFFSERV if your router supports it.
Configuring the CISCO routers to support DIFFSERV:
Router # configure terminal
Router (config) # int S0/0 (This will allow you to access the serial interface of the Cisco or the Wan port).
Router (config--if) # fair-queue( The default value is O.K. Congestive discard threshold = 64 messages, Dynamic Queue = 256, and Reservable Queue = 0).
Router (config-if) # exit
Router (config) # exit
Router # show run (This command will allow you to view and confirm the settings. Confirm that fair queue is enabled on the WAN port).
MultiVOIP set up:
Enable DIFFSERV in the IP settings.
Enabling DIFFSERV causes all voice packets sent out by the MultiVOIP to have the TOS byte set to 0x40.
The binary and hex numbers are 0100 0000 and 0x40 respectively.