BGP学習ノート(一)
BGP aggregate-address
1.
aggregate-address address mask
1.
aggregate-address address mask
1) : BGP aggregate-address 172.16.0.0 255.255.252.0, 172 ,/22 。 BGP show ip bgp :
rtrB#show ip bgp
BGP table version is 20, local router ID is 172.17.1.1
Network Next Hop Metric LocPrf Weight Path
*> 172.16.0.0/24 10.1.1.2 0 0 2 i
*> 172.16.0.0/22 10.1.1.2 0 2 i
*> 172.16.1.0/24 10.1.1.2 0 0 2 i
*> 172.16.2.0/24 10.1.1.2 0 0 2 i
*> 172.16.3.0/24 10.1.1.2 0 0 2 i
2) BGP : BGP , network , redistribute BGP , , BGP 。
Redistribute connected metric 20
aggregate-address 172.16.0.0 255.255.252.0
show ip bgp R1 BGP , (original “?” BGP )
3) BGP 。 RB BGP R C 4 , RA---RB---RC EBGP , RB,RA RC BGP 4 。 RB 4 , RA, ,RA BGP BGP ,AS-PATH “ ” RA AS 。
RB :aggregate-address 172.16.0.0 255.255.252.0
RA :
rtrC#show ip bgp
BGP table version is 32, local router ID is 172.17.1.2
s codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 172.16.0.0/24 172.17.1.1 0 1 2 i
*> 172.16.0.0/22 172.17.1.1 0 1 i
*> 172.16.1.0/24 172.17.1.1 0 1 2 i
*> 172.16.2.0/24 172.17.1.1 0 1 2 i
*> 172.16.3.0/24 172.17.1.1 0 1 2 i
4) BGP 。 、 NULL0 IGP , BGP , BGP 。
ip route 172.16.0.0 255.255.252.0 Null0
redistribute static
,RA origin ?, incomplete。
2.aggregate-address address mask as-set
, AS-PATH , AS , AS#。 AS-SET , AS-PATH , AS-path , R , as-set , AS , AS , 。( as-set , AS-path AS AS )
as-set :*> 172.16.0.0/22 10.1.1.1 0 1 i
:aggregate-address 172.16.0.0 255.255.252.0 as-set
BGP ,
*> 172.16.0.0/22 0.0.0.0 32768 {65530,2} i
AS 。