The maximum number of IP interfaces for 5520 Series is based on the following formulas:
If you disable the VRF scaling boot configuration flag:
For interior node/non boundary node:
#NON DVR IP Interfaces + (# of VRRP interfaces) + (# of RSMLT interfaces) + 2(if IP Shortcuts is enabled) + 3x(# of VRFs) + 1(if DVR node) + (#DVR VLANs if DVR controller) cannot exceed 1000
For boundary node:
#NON DVR IP Interfaces + 2x(# of VRRP interfaces) + 2x(# of RSMLT interfaces) + 2(if IP Shortcuts is enabled) + 7x(# of VRFs) + 1(if DVR node) + 2x(#DVR VLANs if DVR controller) cannot exceed 1000
If you enable the VRF scaling boot configuration flag:
For interior node/non boundary node:
#NON DVR IP Interfaces + (# of VRRP interfaces) + (# of RSMLT interfaces) + 2(if IP Shortcuts is enabled) + 3(if L3VSN is enabled) + 1(if DVR node) + (#DVR VLANs if DVR controller) cannot exceed 1000
For boundary node:
#NON DVR IP Interfaces + 2x(# of VRRP interfaces) + 2x(# of RSMLT interfaces) + 2(if IP Shortcuts is enabled) + 7(if L3VSN is enabled) + 1(if DVR node) + 2x(#DVR VLANs if DVR controller) cannot exceed 1000
For additional detail, see IP Interface Maximums Clarification.