[Boost-users] [asio] Receiving non-UDP multicast frames?

From: Eric Hill (eric_at_[hidden])
Date: 2007-06-06 10:49:27

I have been requested to write a tiny diagnostic application that will  
listen for Cisco Discovery Protocol (CDP) messages from Cisco switches on  
a workstation so that the workstation will "know" what switch port it is  
plugged into.  I have found the following information with my limited  
google-foo:

CDP Packet Format:  
http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm#xtocid12

CDP Information:  
http://www.cisco.com/en/US/products/hw/switches/ps663/products_tech_note09186a0080094713.shtml#cdp

The latter link says that CDP uses a destination multicast address  
01-00-0c-cc-cc-cc, HDLC protocol type 0x2000 on an Ethernet segment.  This  
is where I get lost.  Is that an Ethernet MAC broadcast, or a socket-based  
broadcast?  Can I capture those CDP advertisements with asio?

Eric