I was having trouble finding documentation for this. Is the cdp source-interface command supported under SXI for 6500s?
page 15 says:
12.2(11)T This command was introduced.
12.2(33)SRA This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX This command is supported in the Cisco IOS Release 12.2SX train. Support
in a specific 12.2SX release of this train depends on your feature set,
platform, and platform hardware."