From: https://www.juniper.net/documentation/en_US/junos12.3/topics/reference/general/routing-ptotocols-address-representation.html
"A confederation segment (sequence or set) has a path length of 0. " On 12 June 2017 at 13:53, Aaron Gould <[email protected]> wrote: > I'm working through a Confederation Lab for JNCIP-SP study > > > > Why is r3 choosing that the prefix with the longer AS PATH is better ? > > > > I thought shortest AS Path was typically more attractive > > > > JNCIP book... > https://www.juniper.net/assets/us/en/local/pdf/study- > guide/study-guide-jncip > .pdf > > > > on page 444 of 708 ...the topology is just one page prior... > > > > 4th bullet... > > > > - Configure r1 and r2 to redistribute a 192.168.100/24 static route into > IBGP and ensure that all other routers forward through r1 when its IBGP > session is up. ( i haven't done any tweaks on attributes yet to make r1 > more attractive because i wanted to first understand why r2's path is > preferred from r3's perspective even though it has longer AS PATH ) > > > > i wonder if this has something to do with it - "Inactive reason: Not Best > in > its group - Router ID" > > > > [edit] > > r3@lab-mx104:r3# run show route receive-protocol bgp 10.0.6.1 > 192.168.100.0 > > > > inet.0: 38 destinations, 41 routes (38 active, 0 holddown, 0 hidden) > > Prefix Nexthop MED Lclpref AS path > > 192.168.100.0/24 10.0.6.1 100 I > > > > [edit] > > r3@lab-mx104:r3# run show route receive-protocol bgp 10.0.2.6 > 192.168.100.0 > > > > inet.0: 38 destinations, 41 routes (38 active, 0 holddown, 0 hidden) > > Prefix Nexthop MED Lclpref AS path > > * 192.168.100.0/24 10.0.6.2 100 (65001) > I > > > > [edit] > > r3@lab-mx104:r3# run show route protocol bgp 192.168.100.0 > > > > inet.0: 38 destinations, 41 routes (38 active, 0 holddown, 0 hidden) > > + = Active Route, - = Last Active, * = Both > > > > 192.168.100.0/24 *[BGP/170] 00:51:05, localpref 100, from 10.0.2.6 > > AS path: (65001) I, validation-state: unverified > > > to 10.0.4.2 via lt-0/1/0.32 > > [BGP/170] 00:50:56, localpref 100, from 10.0.6.1 > > AS path: I, validation-state: unverified > > > to 10.0.4.14 via lt-0/1/0.31 > > > > [edit] > > r3@lab-mx104:r3# run show route protocol bgp 192.168.100.0 detail > > > > inet.0: 38 destinations, 41 routes (38 active, 0 holddown, 0 hidden) > > 192.168.100.0/24 (2 entries, 1 announced) > > *BGP Preference: 170/-101 > > Next hop type: Indirect > > Address: 0x2bd4e80 > > Next-hop reference count: 6 > > Source: 10.0.2.6 > > Next hop type: Router, Next hop index: 874 > > Next hop: 10.0.4.2 via lt-0/1/0.32, selected > > Session Id: 0x158 > > Protocol next hop: 10.0.6.2 > > Indirect next hop: 0x2c68110 1048622 INH Session ID: 0x201 > > State: <Active Int Ext> > > Local AS: 65000 Peer AS: 65001 > > Age: 51:08 Metric2: 1 > > Validation State: unverified > > Task: BGP_65001.10.0.2.6+50172 > > Announcement bits (3): 2-KRT 4-BGP_RT_Background 5-Resolve > tree 2 > > AS path: (65001) I > > Accepted > > Localpref: 100 > > Router ID: 10.0.3.4 > > BGP Preference: 170/-101 > > Next hop type: Indirect > > Address: 0x2bd4844 > > Next-hop reference count: 4 > > Source: 10.0.6.1 > > Next hop type: Router, Next hop index: 1099 > > Next hop: 10.0.4.14 via lt-0/1/0.31, selected > > Session Id: 0x152 > > Protocol next hop: 10.0.6.1 > > Indirect next hop: 0x2c68000 1048575 INH Session ID: 0x1fc > > State: <NotBest Int Ext> > > Inactive reason: Not Best in its group - Router ID > > Local AS: 65000 Peer AS: 65000 > > Age: 50:59 Metric2: 1 > > Validation State: unverified > > Task: BGP_65000.10.0.6.1+179 > > AS path: I > > Accepted > > Localpref: 100 > > Router ID: 10.0.6.1 > > > > > > - Aaron Gould > > > > > > _______________________________________________ > juniper-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/juniper-nsp > _______________________________________________ juniper-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/juniper-nsp
