Configuring Authentication PasswordsYou can assign an authentication password for routers in Level 1 and for routers in Level 2.Because Level 1 and Level 2 routers do not communicate with each other, you can assign different passwords for Level 1 routers and forLevel 2 routers. However, if you want the routers in the level to communicate with each other, configure them with the same password.To configure a simple text password, use the following commands.• Configure authentication password for an area.ROUTER ISIS modearea-password [hmac-md5] passwordThe Dell OS supports HMAC-MD5 authentication.This password is inserted in Level 1 LSPs, Complete SNPs, and Partial SNPs.• Set the authentication password for a routing domain.ROUTER ISIS modedomain-password [encryption-type | hmac-md5] passwordThe Dell OS supports both DES and HMAC-MD5 authentication methods.This password is inserted in Level 2 LSPs, Complete SNPs, and Partial SNPs.To view the passwords, use the show config command in ROUTER ISIS mode or the show running-config isis command inEXEC Privilege mode.To remove a password, use either the no area-password or no domain-password commands in ROUTER ISIS mode.Setting the Overload BitAnother use for the overload bit is to prevent other routers from using this router as an intermediate hop in their shortest path first (SPF)calculations. For example, if the IS-IS routing database is out of memory and cannot accept new LSPs, Dell Networking OS sets theoverload bit and IS-IS traffic continues to transit the system.To set or remove the overload bit manually, use the following commands.• Set the overload bit in LSPs.ROUTER ISIS modeset-overload-bitThis setting prevents other routers from using it as an intermediate hop in their shortest path first (SPF) calculations.• Remove the overload bit.ROUTER ISIS modeno set-overload-bitExample of Viewing the Overload Bit SettingWhen the bit is set, a 1 is placed in the OL column in the show isis database command output. The overload bit is set in both theLevel-1 and Level-2 database because the IS type for the router is Level-1-2.Dell#show isis databaseIS-IS Level-1 Link State DatabaseLSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OLB233.00-00 0x00000003 0x07BF 1074 0/0/0496 Intermediate System to Intermediate System
