DOCUMENT:Q168500 09-AUG-2001 [winnt] TITLE :Router Identification Designation in OSPF PRODUCT :Microsoft Windows NT PROD/VER:WinNT:4.0 OPER/SYS: KEYWORDS:kbnetwork ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server version 4.0 - Microsoft Routing and Remote Access Service Update for Windows NT Server version 4.0 ------------------------------------------------------------------------------- SUMMARY ======= Each router running Open Shortest Path First (OSPF) in an Autonomous System (AS) is assigned a 32-bit unique identifier called a router ID. Although it looks like an IP address, it is only used to identify the router and is not an IP address. MORE INFORMATION ================ The router ID is used to identify the router in an Autonomous System and is advertised in the OSPF Hello packets sent between routers. Some OSPF configuration information is determined by the highest router ID. In the case of a tie when determining the designated router in an AS, the highest router ID takes precedence. Although the router need not have any relationship to IP addresses on the router, it is generally accepted practice to make the router ID either the highest or lowest IP address on the router. If the router ID is changed the OSPF protocol should be reinitialized. Additional query words: RRAS ====================================================================== Keywords : kbnetwork Technology : kbWinNTsearch kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbAudDeveloper kbRRASNTSearch kbRRASNT400 Version : WinNT:4.0 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2001.