Cisco core upgrade

The manual on how to upgrade a Catalyst 6509e system with sup720-10G supervisor and Virtual switching system(VSS) is located at: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/15-2SY/config_guide/sup2T/15_2_sy_swcg_2T/enhanced_fast_software_upgrade_efsu.html

For an issu on a stackwise-virtual set of Catalyst 9500 switches see: https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9500/software/release/16-10/configuration_guide/ha/b_1610_ha_9500_cg/configuring_nsf_with_sso.html