{"draft":"draft-ietf-idr-aigp-18","doc_id":"RFC7311","title":"The Accumulated IGP Metric Attribute for BGP","authors":["P. Mohapatra","R. Fernando","E. Rosen","J. Uttaro"],"format":["ASCII","HTML"],"page_count":"15","pub_status":"PROPOSED STANDARD","status":"PROPOSED STANDARD","source":"Inter-Domain Routing","abstract":"Routing protocols that have been designed to run within a single\r\nadministrative domain (IGPs) generally do so by assigning a metric\r\nto each link and then choosing, as the installed path between two\r\nnodes, the path for which the total distance (sum of the metric of\r\neach link along the path) is minimized.  BGP, designed to provide\r\nrouting over a large number of independent administrative domains\r\n(autonomous systems), does not make its path-selection decisions\r\nthrough the use of a metric.  It is generally recognized that any\r\nattempt to do so would incur significant scalability problems as\r\nwell as inter-administration coordination problems.  However, there\r\nare deployments in which a single administration runs several\r\ncontiguous BGP networks.  In such cases, it can be desirable, within\r\nthat single administrative domain, for BGP to select paths based on a\r\nmetric, just as an IGP would do.  The purpose of this document is to\r\nprovide a specification for doing so.","pub_date":"August 2014","keywords":[],"obsoletes":[],"obsoleted_by":[],"updates":[],"updated_by":[],"see_also":[],"doi":"10.17487\/RFC7311","errata_url":null}