Border Gateway Protocol (BGP) BGP, BGP . , , BGP: .

, RIP, OSPF EIGRP, , , BGP (PAs).
BGP:
: BGP 7
BGP- (Path Attributes)
BGP BGP , , , , , BGP .
BGP- , .
- Well-Known Mandatory
- Well-Known Discretionary
- Optional Transitive
- Optional Non-Transitive
, Well-Known. Well-Known , . Optional. Optional , BGP .
mandatory discretionary, Well-Known. Mandatory , . , , . Discretionary, , , .
- . , . , .
1 , TPA1 ATL. , show ip bgp
, BGP. , Next Hop
, Metric (MED)
, LocPrf (Local Preference)
, Weight
, Path (AS Path)
.
TPA1#show ip bgp BGP table version is 4, local router ID is 10.10.10.1 Status codes: s suppressed, d damped, h history, * valid, > best, i internal, r RIB-failure, S Stale Origin codes^ I IGP, e EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path *> 100.100.100.0/24 10.10.10.2 0 200 i
Origin
ORIGIN BGP- , . , : IGP, EGP Incomplete. 1, , Cisco , i
, e
, ?
. , 1, , IGP. , . . IGP , (Gateway Protocol). , OSPF, BGP, BGP. , IGP - , . , , BGP.
EGP (Exterior Gateway Protocol), BGP. .
Incomplete , BGP , . , Border Gateway Protocol - , IGP.
, . , , BGP . . , , , .
AS Path
AS Path - well-known mandatory . , Border Gateway Protocol., 1, , TPA. TPA1, TPA AS 100 AS Path, , , AS iBGP.

TPA1 ATL, 100 . , ATL ATL2 AS. , ATL2 - AS, AS 200. , , AS path, 2, AS, (100), - AS, (342).
2: BGP AS Path

Next Hop
, BGP Next Hop. , , . Next Hop . , , , Next Hop BGP , IGP. , , iBGP eBGP.
, , Next Hop IP- , . . Next Hop hop-by-hop.
BGP, eBGP , Next Hop ( ) IP- eBGP, . IP- eBGP Next Hop, iBGP iBGP. Next Hop, IP-, , . , AS, . , BGP AS-to-AS hop-to-hop.
. , , BGP Next Hop , . , BGP , Next Hop.
, . iBGP , Next Hop , . neighbor
, 3.
ATL (config)# router bgp 200 ATL (config-router)# neighbor 10.10.10.1 next-hop-self
BGP Weight ()
Weight () - BGP, Cisco. , , Cisco , Weight .
Weight , . Weight - , . Weight - 0 65535, , . , 32768. 0.
? , BGP. . , , . - , BGP.
BGP Best Path ( )
, , IGP , . OSPF , . BGP , . BGP. 2 ( ), Cisco BGP.

, , . , - , , BGP. , , .