vrIpOspfExternLsaChecksumSum 1.3.6.1.4.1.562.2.4.1.100.6.7.101.1.4

The 32-bit unsigned sum of the LS checksums of the external link-state database. This sum can be used to determine if there has been a change in a router's link state database, and to compare the link-state database of two routers.