http://okaweb.ec.kyushu-u.ac.jp/lectures/in/

1
????????(????)

• ????
• http//okaweb.ec.kyushu-u.ac.jp/lectures/in/

2
?????????

• AS (Autonomous System)
• ???????????????
• 16???
• IGP (Interior Gateway Protocol)
• AS ???????
• ??????????????
• RIP,OSPF
• EGP (Exterior Gateway Protocol)
• AS ???????
• ??????????????
• BGP

3
???????

• ???????????????????????????????????????

133.5.10.0/24
4
AS,IGP,EGP

• ?????????????????????????????
• ????????????????????????????
• ??????????????????????????????????
• AS??????????????????????????????????????
• IGP
• AS??????????????????????????????
• EGP

5
AS ? EGP

• AS (Autonomous System)
• ???????
• EGP (Exterior Gateway Protocol)
• AS ???????????????
• ?????????????????
• ????????????????

6
RIP
7
RIP (Routing Information Protocol)
???
DST Next Metric 133.5.10.0/24 R0
1 133.5.10.0/24 R1 2
133.5.10.0/24
R2
R0
R1
8
RIP????????

• ???????????????????????
• destination?IP????
• next hop(destination????????)
• metric(1??16??????)
• route change flag(????????????)
• ????
• (RIP2??subnet mask)

9
??????????
133.5.7.0
180????????????????????????????16???????????????
??-????120????????????????
R
????!
133.5.17.0
10
?????????????????
133.5.7.0
???????
R
Metric ? 15
Metric 16
133.5.17.0
11
RIP????

• ????????????????????????????????????????????

133.5.10.0/24
R2
R0
R1
DST Next Metric 133.5.10.0/24 R0
1 133.5.10.0/24 R2 3
DST Next Metric 133.5.10.0/24 R1
2
12
RIP????

• ????????????????????????????????????????????

133.5.10.0/24
R2
R0
R1
DST Next Metric 133.5.10.0/24 R0
1 133.5.10.0/24 R2 3
DST Next Metric 133.5.10.0/24 R1
2
13
Split Horizon

• Simple Split Horizon
• ??????????????????????????????????
• Poison Reverse Update
• ?????????????????????? (15)????????????????

14
Simple Split Horizon

• ??????????????????????????????????

133.5.10.0/24
R2
R0
R1
DST Next Metric 133.5.10.0/24 R0
1
DST Next Metric 133.5.10.0/24 R1
2
15
Poison Reverse Update

• ?????????????????????? (15)????????????????

133.5.10.0/24
R2
R0
R1
DST Next Metric 133.5.10.0/24 R0
1
DST Next Metric 133.5.10.0/24 R1
15
16
Triggered Update

• ???????????????30????????????????????

133.5.10.0/24
R2
R0
R1
DST Next Metric 133.5.10.0/24 R0
1
DST Next Metric 133.5.10.0/24 R1
15
17
RIP2????????

• Subnet Mask?????
• VLSM(Variable Length Subnet Mask)??????
• ?????
• AS??EGP?BGP????????
• ????
• ???????
• 224.0.0.9????????????????????
• Next Hop
• ????????RIP2??????????????

RIP2
RIP2
OSPF
OSPF
18
OSPF
19
RIP???????????????????

• ??????????????????
• version 1?VLSM(Various Length Subnet Mask)???? ?
• version 1?????????????
• version 1??????????
• ?????????????????????
• ??????????????????????????????????????
• ??????????
• ????????(15)???????????

20
RIP (Routing Information Protocol )
???
???
???
???
21
OSPF (Open Shortest Path First )
???
???
???
???
???
???
???
???
??????????????? ??
??(???)???????
22
OSPF (Open Shortest Path First )

• ?????????
• ??????????? OSPF ??????
• ????????
• ????????? OSPF ??????????????(????????????????????
  ??????????????)????????????????
• ???????
• ?????????????????????????????????????

23
????(Neighbor)???
00
01
Hello
Hello
03
Hello
02
Hello
224.0.0.5 ?????????????????????
24
????(Neighbor)?????????
224.0.0.5
?????
?????
?????
25
????????
LSA Link State Advertisement
00
01
03
02
??????????
???????????????????????????????????????????
26
???????
00
N01
01
1
N11
1
1
10
1
N00
10
N10
N12
03
02
1
10
1
1
1
N13
1
N02
27
LSDB (Link State Data Base)
01
02
03
N12
00
N00
N01
N02
N10
N11
N13
00
1
1
1
01
10
1
10
10
1
1
1
02
03
1
1
N00
0
N01
0
0
N02
0
N10
0
0
N11
0
0
N12
0
0
N13
0
0
28
Dijkstra ?Shortest Path First ??????
00
N01
01
1
N11
1
1
10
1
N00
10
N10
N12
03
02
1
10
1
1
1
N13
1
N02
?????????
29
Dijkstra ?Shortest Path First ??????
00
N01
01
1
N11
1
1
10
1
N00
10
N10
N12
03
02
1
10
1
1
1
N13
1
N02
????????????
30
Dijkstra ?Shortest Path First ??????
00
N01
01
1
N11
1
1
10
1
N00
10
N10
N12
03
02
1
10
1
1
1
N13
1
N02
????????????
31
Dijkstra ?Shortest Path First ??????
00
N01
01
1
N11
1
1
10
1
N00
10
N10
03
N12
02
1
10
1
1
1
N13
1
N02
?????????????????
32
??????????
area 0.0.0.1
area 0.0.0.2
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OSPF ???(???)

• ????????????????OSPF??,??????????????????????????
  ???????????????,OSPF??30????,?????????????????????
  ????
• ??????????????????????????????????
• ???????????????OSPF??,?????????????????,?????????
  ????????????????????
• ????????????????OSPF??,????65536???????????????

34
BGP
35
????????????????
???B 214
???A 27
???C 221
?????????!!
36
?????????????????? CIDRClassless Inter-Domain
Routing
???B 214
???A 27
???C 221

• ????????
• ???????????
• ??????????
• ???????

???????????!!
37
?????
1.128.0.0/10
00000001.10000000/10
1.128.0.0/9
1.192.0.0/10
00000001.10000000/9
00000001.11000000/10

• ??????????
• ???????
• ? (network) prefix

38
BGP (Border Gateway Protocol)
network prefix
AS
AS
AS
network prefix
network prefix
network prefix
AS
network prefix
AS
AS
network prefix
network prefix
network prefix
AS
AS
network prefix
39
BGP Peer
AS as-01
network prefix np-00
AS as-00
network prefix np-01
40
BGP ??

• Peer ??????? TCP ???
• ??AS???AS? BGP Peer ????
• IBGP
• AS ?
• EBGP
• AS?
• AS Path (Path Vector) ????????
• ??????
• AS Path ????????????????

41
IBGP ? EBGP
AS 01
AS 00
Interior Border Gateway Protocol
Exterior Border Gateway Protocol
42
AS ??
AS02
AS01
AS04
AS03
AS05
AS04-AS02-AS01 AS04-AS05
43
IBGP??????????

• ??? IBGP ?????????????
• ????AS???????????
• ??????????

44
IBGP??????????(II)

• ????????????????

Cluster ID 00
Cluster ID 01
Route Reflector
45
??????????
AS01
AS02
AS00
AS03
AS05
AS04
AS07
AS06
46
??????????(II)

• ??????????????
• ??AS???????
• ??AS???????
• AUP (Acceptable Use Policy)

AS06
AS04
AS03
AS05
OK
47
????????????(?)
??????????
???? (??????)
APAN (????)
QGPOP (????)
SINET (??)
???? (??????)
OCN (??)
48
BGP ????????????

• POP (Point of Presence)
• NAP (Network Access Point)
• IX,IXP (Internet Exchange Point)

????
????
ISP
ISP
IX
POP,NAP
????
BGP Peer
BGP Peer
BGP Peer
ISP
ISP
ISP
ISP