D-Link DGS-6600-48TS Configuration Guide - Page 302

Volume 4-Layer 3 Configurations / Chapter 30-Border Gateway Protocol (BGP) BGP Configuration commands Command enable [privilege LEVEL] configure terminal router bgp AS-NUMBER bgp always-compare-med Explanation Enter privileged EXEC mode. Enter Global configuration mode. Enter the following information to configure BGP routing process and enter into BGP configuration mode. Enter the following command to enforce MED comparison between all paths. Configuration Example The following example shows you how to configure the Switch to compare the MED from alternative paths, regardless of the autonomous system the paths were received from: dgs-6600:2>enable dgs-6600:15#configure terminal dgs-6600:15(config)#router bgp 65534 dgs-6600:15(config-router)#bgp always-compare-med dgs-6600:15(config-router)# Configuring BGP to Not Use As-Path Factor for Selecting the Best Path Use the bgp bestpath as-path ignore command to configure BGP so that it does not use the as-path factor to select the best path. The following are the best path selection rules: 1) If the next hop associated with the route is unreachable, then the route is dropped. 2) Then route with the largest weight is selected. 3) If the next hop associated with the router is unreachable, then the route is dropped. 4) Then the route with the largest weight is selected. 5) If the weight cannot be determined, then the largest LOCAL_PREF is used to determine the preferred route. 6) If the preferred route still cannot be determined, then the route with the shortest AS_PATH list is preferred. 7) If the preferred route still cannot be determined, then the lowest origin type is preferred. 8) If the preferred route still cannot be determined, then the lowest MED is preferred. 9) If the preferred route still cannot be determined, then eBGP is preferred over iBGP paths. 10) The path with the lowest IGP metric is preferred to the BGP next hop. 11) Determine is multiple paths require installation in the routing table for BGP Multipath. 12) When both paths are external, prefer the path that was received first (the oldest one). Skip this step if the bgp bestpath compare-routerid command is configured. 13) Prefer the route that comes from the BGP router with the lowest router ID. 14) If the originator or router ID is the same for multiple paths, prefer the path with the minimum cluster list length. 15) Prefer the path that comes from the lowest neighbor address. The bgp always-compare-med, bgp bestpath as-path ignore, bgp bestpath compare-router-id or bgp default local-preference commands to customize the path selection process. Command enable [privilege LEVEL] DGS-6600 Configuration Guide Explanation Enter privileged EXEC mode. 302