Quality of Service Using Virtual Channel Translation

Abstract

Virtual channels are used to improve quality of service through a large port count switch. Data frames are sent from one small switch to another small switch within the large port count switch on virtual channels. The use of virtual channels helps prevent congestion caused by a first external source device sending data to a first external destination device from affecting a second external source device sending data to a second external destination device.

1 . A Fibre Channel switch for switching Fibre Channel data frames, the switch comprising:
 a first small Fibre Channel switch; and   a second small Fibre Channel switch coupled to the first small Fibre Channel switch,   wherein each small Fibre Channel switch includes:
 a plurality of ports including a plurality of external ports for coupling to external devices and a plurality of internal ports for connection to a small Fibre Channel switch, wherein the individual links connected to the small switches are organized into a plurality of virtual channels; 
 a plurality of buffers, each buffer associated with a respective virtual channel; and 
 logic operable to determine an identification of a destination of a Fibre Channel data frame for routing purposes based on the destination address of the Fibre Channel data frame and to determine an identification of a virtual channel available for general data flow to apply to received Fibre Channel data frames, wherein the identification of the virtual channel can be done by one of at least two bases, and 
   wherein the first small Fibre Channel switch uses a first basis to identify the virtual channel and the second small Fibre Channel switch uses a second, different basis to identify the virtual channel.   
     
     
         2 . A switch for switching data frames, the switch comprising:
 a first small switch; and   a second small switch coupled to the first small switch,   wherein each small switch includes:
 a plurality of ports including a plurality of external ports for coupling to external devices and a plurality of internal ports for connection to a small switch, wherein the individual links connected to the small switches are organized into a plurality of virtual channels; 
 a plurality of buffers, each buffer associated with a respective virtual channel; and 
 logic operable to determine an identification of a destination of a data frame for routing purposes based on the destination address of the data frame and to determine an identification of a virtual channel available for general data flow to apply to received data frames, wherein the identification of the virtual channel can be done by one of at least two bases, and 
   wherein the first small switch uses a first basis to identify the virtual channel and the second small switch uses a second, different basis to identify the virtual channel.