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#xtocid1... CDP Information: http://www.cisco.com/en/US/products/hw/switches/ps663/products_tech_note0918... 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
Eric Hill wrote:
Is that an Ethernet MAC broadcast, or a socket-based broadcast?
Taking your sentence literally, I think those two things are orthogonal. Your platform might provide a socket-based interface for sending and receiving data at the ethernet layer. (I don't know if that's the case though.)
Can I capture those CDP advertisements with asio?
If there's a socket interface for it, then probably yes. Otherwise, I'm afraid not. Cheers, Chris
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Christopher Kohlhoff -
Eric Hill