BGP????

1
BGP????
???????? 2007?1?
2
????
??? BGP??????? ??? BGP????
3
BGP ????

• BGP???????,???AS????????
• ??????????????
• ?????????
• ???Metric????
• ????????????
• ?????????
• ??CIDR(???????)
• ????????????

4
BGP ???????

• ????TCP,???179
• ???????
• ?????keepalive????TCP????
• ???????????

5
????( Autonomous System )

• ???????(AS)?
• ??????????????
• ???????????--IGP
• ??????????? EGP

6
BGP????
7
BGP????-IBGP?EBGP
AS100
AS300
AS200
8
BGP??????

• ?????,BGP Speaker??????????
• BGP Speaker???????????????
• BGP Speaker?EBGP??????????BGP?????(??EBGP?IBGP)
• ?????,BGP Speaker??????BGP?????????

9
BGP??????
AS200
RTB
AS100
S011.1.1.2/16
S011.1.1.1/16
RTD
S011.4.1.2/24
L11.1.1.1/8
RTA
E011.2.1.1/16
S011.4.1.1/24
E011.2.1.2/16
L211.4.2.1/24
L210.1.1.1/8
RTC
10
BGP??????

• BGP Speaker ?IBGP????????????IBGP???

?IBGP?????????????,BGP?????????? ??,AS???????????
????
11
BGP??????

• BGP Speaker ?IBGP????????????EBGP?????IGP?BGP?????
  ???

12
IBGP???
X 12
X 12
Rtr-A
Rtr-B
IBGP
R-12
AS 12
X 12
AS 14
AS 42
EBGP
R-14
Rtr-D
Rtr-C

• ??IBGP???????????
• ??IBGP???????????

13
??BGP????????????
AS200
18.0.0.1/8
OSPF
RTB
OSPF????18.0.0.1/8 ?IGP(OSPF)????? ???????RTB? BGP
????
14
??BGP????????????
AS200
18.0.0.1/8
OSPF
RTB
OSPF????18.0.0.1/8 ?IGP(OSPF)????? ???????RTB? BGP
????
15
??BGP???????????
AS200
18.0.0.1/8
RTB
????????18.0.0.1/8 ????????????? RTB?BGP????
16
BGP????

• BGP???????
• Open
• KeepAlive
• Update
• Notification

17
BGP???

• BGP?????????,???????????,??????BGP???

Marker(16 byte)
Length(2 byte)
Type(1 byte)
18
Open??

• Open????????????????

19
KeepAlive??

• KeepAlive????????

Marker(16 byte)
Length(2 byte)
Type(1 byte)
20
Update??

• Update??????????????

21
Notification??

• Notification??????????????

???? 1 2 3 4 5 6
???? ???? OPEN??? UPDATE??? ?????? ???? ??
22
BGP??????
23
BGP????????

• ??TCP??BGP???,??open??
• ?????,???????????????,??UPDATE??????????
• ??????????KEEPALIVE?????BGP??????
• ???BGP?????????,???NOTIFICATION????BGP??

24
????
??? BGP??????? ??? BGP????
25
BGP?????

• ????????
• ???????
• ??????
• ????
• ?????16???

26
??BGP????

• 1?Origin
• 2?AS-Path
• 3?Next hop
• 4?MED
• 5?Local-Preference
• 6?Atomic-Aggregate
• 7?Aggregator
• 8?Community

9?Originator-ID 10?Cluster-List 11?Destination
Pref (MCI) 12?Advertiser (Baynet) 13?Rcid-Path
(Baynet) 14?MP_Reach_NLRI 15?MP_Unreach_NLRI 16?Ex
tended_Communities
27
?? (Origin) ??

• ???,????????????Origin??
• ??????????????BGP?????,?origin???IGP
• ?????EGP???,?origin???EGP
• ?????,Origin???? Incomplete

28
AS??(AS-Path)??
D(18.0.0.0/8)
AS300
AS200
RTA
AS400
30.0.0.1
D,dl 400 300 200
30.0.0.2
RTB
AS100
AS500
D,d2 500 200
D,d1 400 300 200 gtD,d2 500 200
29
???
?
RTA
Network10.0.0.0/8 AS-Path387 213
RTC
RTB
AS 213 10.0.0.0/8
Network10.0.0.0/8 AS-Path213
RTA???????????
30
????AS-Path
????
2 Mbps
AS 462
Network10.0.0.0/8 AS-Path462 123
2 Mbps
RTA
RTB
64 kbps
AS 123 10.0.0.0/8
????
AS 387
?????AS-number ??? AS-path??
31
???(Next Hop)??
RTA ?????10.0.0.2??18.0.0
.0/8 ?????10.0.0.3??20.0.0.0/8 ?????21.0.0.1??19.0
.0.0/8
RTC ?????10.0.0.1??19.0
.0.0/8 ?????10.0.0.3??20.0.0.0/8
AS200
RTC
EBGP
RTA
18.0.0.0/8
10.0.0.1
AS100
21.0.0.2
10.0.0.2
IBGP
IBGP
20.0.0.0/8
21.0.0.1
10.0.0.3
RTD
19.0.0.0/8
RTB
RTB ?????10.0.0.2??18.0.0.
0/8 ?????10.0.0.3??20.0.0.0/8
32
???????(Local-preference)
33
MED(Multi-Exit-DISC)??
34
BGP????

• ????
• ?RTC???????RTA???(MED???)?????

192.10.0.0/16
E0
E0
35
??(Community)??

• ?????????????????,??????????????????,?????????????
  
• no-export
• ??????/AS??BGP???
• no-advertise
• ??????BGP???
• local-AS
• ????EBGP???
• Internet
• ??????????

36
BGP??????

• ????,??BGP????????
• ????????????,?????
• ????????????
• ????????????(???????)
• ??AS???????
• ?????????IGP,EGP,Incomplete?????
• ??MED?????
• ??RouterID?????

37
? ?

• BGP?????
• BGP?????
• BGP?????

38
RFCs of BGP4

• 1930 Autonomous System???,???????
• 1774 BGP-4 ????
• 1773 BGP-4 ??????
• 1772 BGP?Internet????
• 1771 ????Border Gateway Protocol 4 (BGP-4)
• 1745 BGP4?IGP---OSPF ????
• 1675 BGP MIB

39
RFCs of BGP4

• 1965 BGP ?Autonomous System ??
• 1997 BGP ????
• 1998 BGP ??????????????
• 2385 ??MD5????BGP????
• 2796 IBGP?????? Vs. ?????

40
RFCs of BGP4 ??

• 2842 BGP-4 ????
• 2858 BGP-4 ?MP-BGP???
• 2918 BGP-4?????

41
??!