In 3550 does not support SIP Method in 12.4 T also.Cross-Platform Release Notes for Cisco IOS Release 12.4T, Part 2: Platform-Specific Information:http://www.cisco.com/en/US/products/ps6441/prod_release_note09186a00804a19a2.html
For interfaces that operate at 20,000,000 (20 million) bits per second or less, you must use 32-bit byte and packet counters. For interfaces that operate faster than 20 million bits per second, and slower than 650,000,000 bits per second, you must us...
RSPAN consists of at least one RSPAN source session, an RSPAN VLAN, and at least one RSPAN destination session. You separately configure RSPAN source sessions and RSPAN destination sessions on different network devices. To configure an RSPAN source s...