??? NetSim-IP ????-RIP?IGRP?EIGRP?OSPF

1
??? NetSim-IP ????-RIP?IGRP?EIGRP?OSPF

• ????
• ???????????
• ??RIP?IGRP?EIGRP?OSPF????,?????(dynamic)???,??????
  ?,??????????tracert??

2
????(????)

• ???????????????????,????????????????,?????????????
  ???????,???????????????,???????????????????????,??
  ???????,???????????,??????????,??????????
• ??????????????????,????????????,??????????????
• ??????????????????????????,????Internet?,?????????
  ????,????????????????????????????????????????????,
  ??????????????

3
????????

• ???????????????????????,????????,?????????????????
  ??????,?????????????,???????(routing
  update)????????????????????,?????????????????
• ???????????,??????????????,???????????????????,???
  ?????????????,??????????,??????????????,??????????
  ??????????????,??????????????,??????

4
????????

• ??????????,??????????????????????????????,????????
  ?,?????????,????????????????????,?????????????????
  ?????,?????????????,???????????????????????????,??
  ????????????,????????
• ??????????(convergence),??????????????????????????
  ?,???????????

5
??????

• ???(Optimality)???????????????????????,??????????
  ?????????????????
• ??(Flexibility)??????????????,?????????????,?????
  ?????????????????????????,?????????????,??????????
  ???????????????
• ????(Rapid convergence)?????????,????????????????
  ?????,??????????,???????????????,???????????,?????
  ????????
• ???????(Robustness Simplicity)????????,????????
  ???,??????????????????????,???????????,???????????
  ??????????????,?????????

6
??????

• ???????????????????,????????????????
• ??????(Interior Gateway ProtocolIGP)
• ??????(Exterior Gateway ProtocolEGP)

7
??????

• IGP?????
• ??????(Routing Information ProtocolRIP)
• ????????(Interior Gateway Routing ProtocolIGRP)
• ???????????(Open Shortest Path FirstOSPF)
• ???????????(Enhanced Interior Gateway Routing
  ProtocolEIGRP)
• EGP????
• ??????(Border Gateway ProtocolBGP)
• ??????(Exterior Gateway ProtocolEGP)

8
??????

• ?????????????,???????????,?????????????,?????????
  ????,?????????????,???????,?????????????????????,?
  ??????????
• ?????????????????,?????????????????,????????????,
  ?????????????,????????????????????????,???????????
  ?????????????????

9
??????

• ?????????????????????????,????????????????,??????
  ??????????????????????
• ?????????????????????,??????????,?????????????????
  ???????????????????,???????

10
??????

• ???????????????????????????,???????????????,?????
  ????????????
• ?????????????????????????????,??????????IGP,?????
  ?????EGP?

11
??????

• ?????????
• ??????(distance-vector)???????????????,??????????
  ????,??????????,??????????????????,???????,???????
  ????,????????????,????????????????,??????????????
  ??????????????

12
??????

• ????????????????????,?????????????,??????????????
  ???????,??????????????????????????,???????????????
  ???????????????????????????,??,???????????????,???
  ?????????????(Link State AdvertisementLSA),??????
  ?????????,??LSA??????????????,????????????????????
  LSA,?????????????????

13
RIP??

• RIP?????????????????IGP??,?????????,??????????,???
  ??????RFC1058?RFC1723?RIP????UDP?????????,?30?????
  ??????,??????????????,???????????????????????,????
  ??????,RIP??????????????,????????????,????????????
  ?,???????????

14
RIP??

• RIP??????(hop count)???????????,??????????????????
  ???????????????????????????????,???????,?RIP??????
  ??????RIP?????????15,???????????????????????15,???
  16??????????,?????RIP??????????????

15
IGRP??

• IGRP?????????????,??Cisco??????????????IGRP???????
  ?RIP??15???????,??Cisco??????????,????RIP?????,???
  IGRP,???????????????,???????????????
• ???????,IGRP?90???????????,?3??????(?270?),???????
  ???????????,?????????????7??????630??,Cisco
  IOS?????????????

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IGRP??

• ?????????????????,IGRP?????????????,??????????????
  ????????????
• IGRP??????????????,??????RIP???,????IGRP?Cisco????
  ?,????????????????

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EIGRP??

• EIGRP????Cisco?1990??????,????,??IGRP?????,???????
  IGRP?????,??????????????????
• EIGRP?IGRP??????,????????????????????,???????EIGRP
  ?????????IGRP?????,?????????????,EIGRP??????????,
  ?????????????????????

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EIGRP??

• EIGRP?????
• ??????????,???????
• ????????????(Variable Length Subnet
  MaskingVLSM)?
• ?????????
• EIGRP???RIP??IGRP?????????,???????????????????????
  ,??????????,?????????,?????????????????,?????????
  ??,??EIGRP???????,??????????

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OSPF??

• OSPF?????IGP??,?????????(autonomous
  systemAS)???????RIP??,OSPF???????,?RIP??????????
• ??OSPF???????????,??RIP?IGRP????????????????,OSPF?
  ??LSA??????????????,???????LSA?????????????,??????
  ?????SPF???,?????????????????

20
OSPF??

• ?OSPF???,???????????????,????????,????????????????
  ,??????????????????????,?????????????????????,??,?
  ??????????????,?????????????????????

21
Routing Categories

• ??????????
• ????(Distance Vector)
• ?RIP?IGRP
• ????(Link State)
• ?OSPF
• ?????(Hybrid) ?EIGRP

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Routing Categories
???? ????
??????????? ???????????????????????
??????????? ???????????????
?????????,????? ??????????,?????
?????????????? ?????????????????????????
???????????????? ???????????????,???????????????????????
???????? ?????????????????????
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Shortest Path Approaches

• Distance Vector Protocols
• Neighbors exchange list of distances to
  destinations
• Best next-hop determined for each destination
• Ford-Fulkerson (distributed) shortest path
  algorithm
• Link State Protocols
• Link state information flooded to all routers
• Routers have complete topology information
• Shortest path ( hence next hop) calculated
• Dijkstra (centralized) shortest path algorithm

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Distance Vector

• Table Synthesis
• Neighbors exchange table entries
• Determine current best next hop
• Inform neighbors
• Periodically
• After changes

• Local Signpost
• Direction
• Distance
• Routing Table
• For each destination list
• Next Node
• Distance

25
Iteration Node 1 Node 2 Node 3 Node 4 Node 5
Initial (-1, ?) (-1, ?) (-1, ?) (-1, ?) (-1, ?)
1
2
3
Table entry _at_ node 3 for dest SJ
Table entry _at_ node 1 for dest SJ
San Jose
26
Iteration Node 1 Node 2 Node 3 Node 4 Node 5
Initial (-1, ?) (-1, ?) (-1, ?) (-1, ?) (-1, ?)
1 (-1, ?) (-1, ?) (6,1) (-1, ?) (6,2)
2
3
1
0
San Jose
2
27
Iteration Node 1 Node 2 Node 3 Node 4 Node 5
Initial (-1, ?) (-1, ?) (-1, ?) (-1, ?) (-1, ?)
1 (-1, ?) (-1, ?) (6, 1) (-1, ?) (6,2)
2 (3,3) (5,6) (6, 1) (3,3) (6,2)
3
3
1
3
0
San Jose
2
6
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Iteration Node 1 Node 2 Node 3 Node 4 Node 5
Initial (-1, ?) (-1, ?) (-1, ?) (-1, ?) (-1, ?)
1 (-1, ?) (-1, ?) (6, 1) (-1, ?) (6,2)
2 (3,3) (5,6) (6, 1) (3,3) (6,2)
3 (3,3) (4,4) (6, 1) (3,3) (6,2)
1
3
3
0
San Jose
6
4
2
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Iteration Node 1 Node 2 Node 3 Node 4 Node 5
Initial (3,3) (4,4) (6, 1) (3,3) (6,2)
1 (3,3) (4,4) (4, 5) (3,3) (6,2)
2
3
1
5
3
3
0
San Jose
4
2
Network disconnected Loop created between nodes
3 and 4
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Iteration Node 1 Node 2 Node 3 Node 4 Node 5
Initial (3,3) (4,4) (6, 1) (3,3) (6,2)
1 (3,3) (4,4) (4, 5) (3,3) (6,2)
2 (3,7) (4,4) (4, 5) (5,5) (6,2)
3
5
7
3
5
3
0
San Jose
2
4
Node 4 could have chosen 2 as next node because
of tie
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Iteration Node 1 Node 2 Node 3 Node 4 Node 5
Initial (3,3) (4,4) (6, 1) (3,3) (6,2)
1 (3,3) (4,4) (4, 5) (3,3) (6,2)
2 (3,7) (4,4) (4, 5) (5,5) (6,2)
3 (3,7) (4,6) (4, 7) (5,5) (6,2)
7
5
7
0
5
San Jose
2
4
6
Node 2 could have chosen 5 as next node because
of tie
32
Iteration Node 1 Node 2 Node 3 Node 4 Node 5
1 (3,3) (4,4) (4, 5) (3,3) (6,2)
2 (3,7) (4,4) (4, 5) (2,5) (6,2)
3 (3,7) (4,6) (4, 7) (5,5) (6,2)
4 (2,9) (4,6) (4, 7) (5,5) (6,2)

7
7
9
5
0
San Jose
6
2
Node 1 could have chose 3 as next node because of
tie
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Counting to Infinity Problem
Nodes believe best path is through each
other (Destination is node 4)
Update Node 1 Node 2 Node 3
Before break (2,3) (3,2) (4, 1)
After break (2,3) (3,2) (2,3)
1 (2,3) (3,4) (2,3)
2 (2,5) (3,4) (2,5)
3 (2,5) (3,6) (2,5)
4 (2,7) (3,6) (2,7)
5 (2,7) (3,8) (2,7)

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Routing Loop Solutions

• ????
• ?????????
• ???? (Split Horizon)
• ????????? (Hold-Down)
• ??????(Poison Reverse Updates)

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Link-State Algorithm

• Basic idea two step procedure
• Each source node gets a map of all nodes and link
  metrics (link state) of the entire network
• Find the shortest path on the map from the source
  node to all destination nodes
• Broadcast of link-state information
• Every node i in the network broadcasts to every
  other node in the network
• IDs of its neighbors Niset of neighbors of i
• Distances to its neighbors Cij j ?Ni
• Flooding is a popular method of broadcasting
  packets

36
Execution of Dijkstras algorithm
?
?
?
?
Iteration N D2 D3 D4 D5 D6
Initial 1 3 2 5 ? ?
1 1,3 3 2 4 ? 3
2 1,2,3 3 2 4 7 3
3 1,2,3,6 3 2 4 5 3
4 1,2,3,4,6 3 2 4 5 3
5 1,2,3,4,5,6 3 2 4 5 3
?
?
?
?
?
37
Shortest Paths in Dijkstras Algorithm
38
Routed Protocol

• ??????(Routed Protocol?Routable Protocol) ????
• IP
• IPX
• AppleTalk
• DecNET

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Routing Protocol

• ????????
• ??????(interior gateway protocol)
• ??????(external gateway protocol)
• ?????????????,??????,? ?????????
• ????????,??????,?????? ????
• ?????????
• RIP?RIPv2?OSPF?IGRP?EIGRP?IS-IS?BGP

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Timers Basics
RIP?IGRP???????
  RIP IGRP
Update 30 90
Invalid 90 270
Hold-Down 240 Update x 3 10
Flush   Update x 7
40
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Default Distances
Route Source Default Distance
Directly Connected Interface 0
Static Route 1
Enhanced IGRP Summary Route 5
External BGP 20
Internal Enhanced IGRP 90
IGRP 100
OSPF 110
IS-IS 115
RIP 120
EGP 140
Internal BGP 200
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Summary

•  IGRP?EIGRP?????????Cisco???
  ??,?Cisco??????????
• ???????????????,????? ??????,????????????
• ????????????????????? ??

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????(??RIP????)

• ??RIP???????????????????????????RIP??????????2???,
  ?????????RIP???????????RIP,???router
  rip???,????????????,?????????Router
  (config-router),????RIP?????????,???network
  lt????gt????
• ??????????,?????????????,????????????????????????C
  lass A?B?C??????,?????????????????,??????????B???1
  72.16.0.0,???5?C?????????RIP???,????????172.16.0.0
  ???

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??(Router 1)RIP????
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??RIP????

• ??RIP???????????UDP?????????,???????(??????????)??
  ???,????????????(Router 1)???(Router
  2)???????(Router 1)???(Router 3)?????????????

46
????(Router 1)???(Router 2)????
47
????(Router 1)???(Router 3)????
48
PC1 tracert PC2??????
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RIPv2

• ????RIPv2????(config-router)??????version 2?????
• ???RIP?????????????passive-interface??,????????RIP
  ?????,??
• (config-router) passive-interface serial 0
• ??debug ip rip?????????RIP??????,no debug ip
  rip????????

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??IGRP????

• ??IGRP??????????RIP???????,????RIP???????,?????no
  router rip??????
• IGRP??????
• router igrp ltAS??gt
• IGRP???RIP????,???AS??,AS???????????,IGRP?????????
  ?????(IGP),??????????????????????AS 100?

51
??IGRP????
52
??IGRP????

• ??IGRP?????????????UDP?????????,???????(??????????
  )?????,????????????(Router 1)???(Router
  2)???????(Router 1)???(Router 3)?????????????

53
????(Router 1)???(Router 2)????
54
????(Router 1)???(Router 3)????
55
PC1 tracert PC2??????
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??IGRP????

• ?????IGRP?????????????passive-interface??,??debug
  ip igrp events?????????IGRP??????,debug ip igrp
  transactions??????????????????,undebug
  all??????????debug???

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??EIGRP????

• ??EIGRP??????????IGRP???????,????IGRP?????????no
  router igrp ltAS??gt??????
• EIGRP???IGRP????,EIGRP??????
• router eigrp ltAS??gt

58
??EIGRP????
59
??EIGRP????

• ?????EIGRP?????????????passive-interface??,??show
  ip eigrp?????????EIGRP???????

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??OSPF????

• ??OSPF??????????EIGRP???????,????IGRP?????????no
  router eigrp ltAS??gt??????OSPF???EIGRP????,????????
  ????,??????
• network lt????gt lt????gt area ltarea??gt
• ??????NetSim-Cisco?????????????,?????????????????,
  ???????????255.255.255.0??????0.0.0.255?area??????
  ??????????????????

61
??OSPF????
62
????

1. ???????????????????????
2. ????????????????
3. ???????????????
4. ??????????
5. ?????????????????,?????
6. ?????????????????
7. ?????????????????
8. ????????,?????????????????
9. ???????????????????
10. ?????????????
11. ????OSPF??????
12. ?????????????????