BGP
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, , , BGP , , . , BGP.

BGP:
BGP-
, BGP AS-to-AS, , BGP (.. eBGP) . , eBGP, - , , . , . , BGP :
- (TTL), time-to-live
1
. EBGP. - , .
eBGP - TCP-, . , . BGP, , , TCP-, TCP- 179
. BGP TCP- 179
, . . BGP , , . , .
IPv6? , , BGP IPv6, IPv6. eBGP ( iBGP) IPv6- , IPv4 . eBGP, :
- BGP AS (
router bgp local_as_number
). - eBGP IP- AS (
neighbor ip-_of_neighbor remote-as remote_as_number
).
1 EBGP TPA1 ATL.

1: eBGP
ATL#conf t Enter configuration commands, one per line. End with CNTL/Z. ATL(config)#router bgp 220 ATL(config-router)#neighbor 30.30.30.1 remote-as 110 ATL(config-router)#end ATL# TPAl#conf t Enter configuration commands, one per line. End with CNTL/Z. TPA1(config)router bgp 110 TPA1(config-router)#neighbor 30.30.30.2 remote-as 220 TPA1(config-router)#end TPA1# TPAl#show ip bgp summary BGP router identifier 30.30.30.1, local AS number 110 BGP table version is 4, main routing table version 4 1 network entries using 120 bytes of memory 1 path entries using 52 bytes of memory 1/1 BGP path/bestpath attribute entries using 124 bytes of memory 1 BGP AS-PATH entries using 24 bytes of memory 0 BGP route-map cache entries using 0 bytes of memory 0 BGP filter-list cache entries using 0 bytes of memory BGP using 320 total bytes of memory BGP activity 2/1 prefixes, 2/1 paths, scan interval 60 secs Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 30.30.30.2 4 220 413 414 4 0 0 06:12:46 1 TPA1#
: BGP,debug ip bgp
, . . , ,show ip bgp neighbors
.
eBGP , IPv6, , IPv4. , IPv4 IPv6 . Cisco BGP (NLRI) BGP. 2 IPv6.
2: EBGP IPv6
ATL#conf t Enter configuration commands, one per line. End with CNTL/Z. ATL(config)#router bgp 220 ATL(config-router)#neighbor 2201:1212:1212::2 remote-as 110 ATL(config-router-af)#neighbor 2201:1212:1212::2 activate ATL(config-router-af)#end ATL#
iBGP-
, , - . , iBGP-. iBGP, TPA1 TPA2? . , , . , BGP, , , (Split Horizon Rule) iBGP. , iBGP iBGP. , iBGP .
, iBGP, . , , , BGP, ? , ?
loopback- . , BGP, , . , Cisco , loopback IP- .
: iBGP , loopback- BGP. (IGP), OSPF EIGRP.
3 iBGP TPA TPA1. , , .
3: iBGP
TPA#conf t Enter configuration commands, one per line. End with CNTL/Z. TPA(config)router bgp 110 TPA(config-router)#neighbor 8.8.8.8 remote-as 110 TPA(config-router)#neighbor 8.8.8.8 update-source loopbackO TPA(config-router)#end TPA# TPAl#conf t Enter configuration commands, one per line. End with CNTL/Z. TPA1(config)#router bgp 110 TPA1(config-router)#neighbor 5.5.5.5 remote-as 110 TPA1(config-router)#neighbor 5.5.5.5 update-source loopbackO TPA1(config-router)#end TPA1#
eBGP Multihop
eBGP- , , . iBGP loopback . : , eBGP ? , loopback eBGP, . , loopback ?
BGP eBGP multihop. eBGP multihop . BGP TTL 1, . ? BGP , eBGP multihop. 4 eBGP multihop TPA1 ATL. multihop, loopback .
4: eBGP Multihop
ATL#conf t Enter configuration commands, one per line. End with CNTL/Z. ATL(config)#router bgp 220 ATL(config-router)#neighbor 8.8.8.8 remote-as 110 ATL(config-router)#neighbor 8.8.8.8 update-source loopbackO ATL(config-router)#neighbor 8.8.8.8 ebgp-multihop 2 ATL(config-router)#end ATL# TPAl#conf t Enter configuration commands, one per line. End with CNTL/Z. TPA1(config)router bgp 110 TPA1(config-router)#neighbor 7.7.7.7 remote-as 220 TPA1(config-router)#neighbor 7.7.7.7 update-source loopbackO TPA1(config-router)#neighbor 7.7.7.7 ebgp-multihop 2 TPA1(config-router)#end TPA1#
BGP
BGP, . , BGP, , - , . , (eBGP iBGP) - .
Cisco . (.. ) , . , ( ) . service password-encryption
, .
Message Digest 5 (MD5) . 5 , TPA1 ATL.
5. BGP-
ATL#conf t Enter configuration commands, one per line. End with CNTL/Z. ATL(config)#router bgp 220 ATL(config-router)#neighbor 8.8.8.8 remote-as 110 ATL(config-router)#neighbor 8.8.8.8 update-source loopbackO ATL(config-router)#neighbor 8.8.8.8 ebgp-multihop 2 ATL(config-router)#neighbor 8.8.8.8 password MySuperSecret121 ATL(config-router)#end ATL# TPAl#conf t Enter configuration commands, one per line. End with CNTL/Z. TPA1(config)router bgp 110 TPA1(config-router)#neighbor 7.7.7.7 remote-as 220 TPA1(config-router)#neighbor 7.7.7.7 update-source loopbackO TPA1(config-router)#neighbor 7.7.7.7 ebgp-multihop 2 ATL(config-router)#neighbor 7.7.7.7 password MySuperSecret121 TPA1(config-router)#end TPA1#