yuna_admirer
24-11-2002, 23:27
Tui post phần debug của OSPF process lên , bà con tự xem nhé :
R1#debug ip packet
IP packet debugging is on
R1#
R1#
00:34:15: IP: s=172.16.12.1 (local), d=224.0.0.5 (Serial0), len 64, sending
broad/multicast
00:34:16: IP: s=10.0.0.3 (Ethernet0), d=224.0.0.5, len 84, rcvd 0
00:34:16: IP: s=172.16.12.2 (Serial0), d=224.0.0.5, len 84, rcvd 0
00:34:16: IP: s=172.16.12.1 (local), d=224.0.0.5 (Serial0), len 84, sending
broad/multicast
00:34:16: IP: s=10.0.0.5 (Ethernet0), d=224.0.0.5, len 84, rcvd 0
00:34:16: IP: s=10.0.0.1 (local), d=224.0.0.6 (Ethernet0), len 84, sending
broad/multicast
00:34:16: IP: s=10.0.0.3 (Ethernet0), d=224.0.0.5, len 64, rcvd 0
00:34:17: IP: s=172.16.12.2 (Serial0), d=224.0.0.5, len 68, rcvd 0
00:34:17: IP: s=10.0.0.5 (Ethernet0), d=224.0.0.5, len 72, rcvd 0
00:34:17: IP: s=10.0.0.5 (Ethernet0), d=10.0.0.1, len 84, rcvd 0
00:34:17: IP: s=172.16.12.1 (local), d=224.0.0.5 (Serial0), len 84, sending
broad/multicast
00:34:17: IP: s=172.16.12.2 (Serial0), d=224.0.0.5, len 84, rcvd 0
00:34:18: IP: s=172.16.12.2 (Serial0), d=224.0.0.5, len 80, rcvd 0
00:34:18: IP: s=10.0.0.1 (local), d=10.0.0.5 (Ethernet0), len 84, sending
00:34:18: IP: s=10.0.0.3 (Ethernet0), d=224.0.0.5, len 80, rcvd 0
00:34:18: IP: s=10.0.0.5 (Ethernet0), d=10.0.0.1, len 84, rcvd 0
00:34:18: IP: s=10.0.0.1 (local), d=224.0.0.6 (Ethernet0), len 80, sending
broad/multicast
00:34:18: IP: s=10.0.0.5 (Ethernet0), d=10.0.0.1, len 64, rcvd 0
00:34:18: IP: s=172.16.12.1 (local), d=224.0.0.5 (Serial0), len 84, sending
broad/multicast
00:34:18: IP: s=172.16.12.2 (Serial0), d=224.0.0.5, len 84, rcvd 0
00:34:18: IP: s=172.16.12.1 (local), d=224.0.0.5 (Serial0), len 68, sending
broad/multicast
00:34:18: IP: s=10.0.0.1 (local), d=224.0.0.5 (Ethernet0), len 72, sending
broad/multicast
00:34:18: IP: s=10.0.0.5 (Ethernet0), d=224.0.0.5, len 84, rcvd 0
00:34:20: IP: s=10.0.0.3 (Ethernet0), d=224.0.0.5, len 84, rcvd 0
00:34:20: IP: s=10.0.0.1 (local), d=224.0.0.6 (Ethernet0), len 84, sending
broad/multicast
00:34:20: IP: s=172.16.12.1 (local), d=224.0.0.5 (Serial0), len 64, sending
broad/multicast
R1#u a
00:34:22: IP: s=10.0.0.3 (Ethernet0), d=224.0.0.5, len 72, rcvd 0
00:34:23: IP: s=172.16.12.2 (Serial0), d=224.0.0.5, len 84, rcvd 0
00:34:23: IP: s=10.0.0.3 (Ethernet0), d=224.0.0.5, len 84, rcvd 0
00:34:23: IP: s=10.0.0.1 (local), d=224.0.0.6 (Ethernet0), len 84, sending
broad/multicast
00:34:23: IP: s=10.0.0.5 (Ethernet0), d=10.0.0.1, len 84, rcvd 0
00:34:23: IP: s=10.0.0.5 (Ethernet0), d=224.0.0.5, len 84, rcvd 0ll
All possible debugging has been turned off
R1#
00:34:23: IP: s=10.0.0.5 (Ethernet0), d=224.0.0.5, len 80, rcvd 0
00:34:23: IP: s=172.16.12.1 (local), d=224.0.0.5 (Serial0), len 80, sending
broad/multicast
00:34:23: IP: s=172.16.12.2 (Serial0), d=224.0.0.5, len 80, rcvd 0
00:34:23: IP: s=10.0.0.3 (Ethernet0), d=224.0.0.5, len 84, rcvd 0
00:34:23: IP: s=172.16.12.2 (Serial0), d=224.0.0.5, len 84, rcvd 0
00:34:23: IP: s=172.16.12.1 (local), d=224.0.0.5 (Serial0), len 84, sending
broad/multicast
00:34:23: IP: s=10.0.0.5 (Ethernet0), d=224.0.0.5, len 84, rcvd 0
R1#
[b]Liwh à , cái debug interface state machine vì một lý do nào đó đã "biến mất" cu có giử thì post lên nhé.
yuna_admirer
25-11-2002, 13:25
Tiếp tục post : Đây là hoạt động của OSPF sau khi database đã build xong . OSPF chạy thuật giải SPF ( nói sau) để build bảng Route :
router s ospf 1
Rub(config-router)#area 1 stub
Rub(config-router)#^Z
Rub#
Rub#
02:02:22: %SYS-5-CONFIG_I: Configured from console by console
02:02:23: OSPF: running SPF for area 1
02:02:23: OSPF: Initializing to run spf
02:02:23: It is a router LSA 192.168.30.1. Link Count 3
02:02:23: Processing link 0, id 192.168.30.10, link data 192.168.30.9, type 1
02:02:23: No RTR Back link
02:02:23: Processing link 1, id 192.168.30.8, link data 255.255.255.248, type 3
02:02:23: Add better path to LSA ID 192.168.30.15, gateway 192.168.30.8, dist 64
02:02:23: Add path: next-hop 192.168.30.9, interface Serial1
02:02:23: Processing link 2, id 192.168.30.1, link data 255.255.255.255, type 3
02:02:23: Add better path to LSA ID 192.168.30.1, gateway 192.168.30.1, dist 1
02:02:23: Add path: next-hop 192.168.30.1, interface Loopback1
02:02:23: OSPF: Adding Stub nets
02:02:23: OSPF: delete lsa id 192.168.30.1, type 0, adv rtr 192.168.30.1 from delete list
02:02:23: OSPF: insert route list LS ID 192.168.30.1, type 0, adv rtr 192.168.30.1
02:02:23: OSPF: delete lsa id 192.168.30.15, type 0, adv rtr 192.168.30.1 from delete list
02:02:23: OSPF: insert route list LS ID 192.168.30.15, type 0, adv rtr 192.168.30.1
02:02:23: OSPF: Entered old delete routine
02:02:23: OSPF: Delete path to router 192.168.30.10 via 192.168.30.10 spf 13
02:02:23: OSPF: delete lsa id 192.168.30.10, type 1, adv rtr 192.168.30.10 from delete list
02:02:23: OSPF: running spf for summaries area 1
02:02:23: OSPF: Start processing Summary LSA 192.168.10.0, mask 255.255.255.224, adv 192.168.30.10, age 74, seq 0x80000004 (Area 1)
02:02:23: OSPF: ABR not reachable 192.168.30.10
02:02:23: OSPF: Start processing Summary LSA 192.168.10.32, mask 255.255.255.240, adv 192.168.30.10, age 74, seq 0x80000003 (Area 1)
02:02:23: OSPF: ABR not reachable 192.168.30.10
02:02:23: OSPF: Start processing Summary LSA 192.168.20.0, mask 255.255.255.252, adv 192.168.30.10, age 74, seq 0x80000004 (Area 1)
02:02:23: OSPF: ABR not reachable 192.168.30.10
02:02:23: OSPF: Start processing Summary LSA 192.168.20.2, mask 0.0.0.0, adv 192.168.30.10, age 74, seq 0x80000001 (Area 1)
02:02:23: OSPF: ABR not reachable 192.168.30.10
02:02:23: OSPF: sum_delete_old_routes area 1
02:02:23: OSPF: sum-Deleting old route 192.168.20.2
02:02:23: OSPF: Delete path to router 192.168.20.2 via 192.168.30.10 spf 13
02:02:23: OSPF: sum-Deleting old route 192.168.20.0
02:02:23: OSPF: sum-Deleting old route 192.168.10.32
02:02:23: OSPF: sum-Deleting old route 192.168.10.0
02:02:23: OSPF: delete lsa id 192.168.20.2, type 4, adv rtr 192.168.30.10 from delete list
02:02:23: OSPF: delete lsa id 192.168.20.0, type 3, adv rtr 192.168.30.10 from delete list
02:02:23: OSPF: delete lsa id 192.168.10.32, type 3, adv rtr 192.168.30.10 from delete list
02:02:23: OSPF: delete lsa id 192.168.10.0, type 3, adv rtr 192.168.30.10 from delete list
02:02:23: OSPF: Started Building Type 5 External Routes
02:02:23: OSPF: ex_delete_old_routes
02:02:23: OSPF: Started Building Type 7 External Routes
02:02:23: OSPF: ex_delete_old_routes
02:02:33: OSPF: running SPF for area 1
02:02:33: OSPF: Initializing to run spf
02:02:33: It is a router LSA 192.168.30.1. Link Count 2
02:02:33: Processing link 0, id 192.168.30.8, link data 255.255.255.248, type 3
02:02:33: Add better path to LSA ID 192.168.30.15, gateway 192.168.30.8, dist 64
02:02:33: Add path: next-hop 192.168.30.9, interface Serial1
02:02:33: Processing link 1, id 192.168.30.1, link data 255.255.255.255, type 3
02:02:33: Add better path to LSA ID 192.168.30.1, gateway 192.168.30.1, dist 1
02:02:33: Add path: next-hop 192.168.30.1, interface Loopback1
02:02:33: OSPF: Adding Stub nets
02:02:33: OSPF: delete lsa id 192.168.30.1, type 0, adv rtr 192.168.30.1 from delete list
02:02:33: OSPF: insert route list LS ID 192.168.30.1, type 0, adv rtr 192.168.30.1
02:02:33: OSPF: delete lsa id 192.168.30.15, type 0, adv rtr 192.168.30.1 from delete list
02:02:33: OSPF: insert route list LS ID 192.168.30.15, type 0, adv rtr 192.168.30.1
02:02:33: OSPF: Entered old delete routine
02:02:33: OSPF: running spf for summaries area 1
02:02:33: OSPF: Start processing Summary LSA 192.168.10.0, mask 255.255.255.224, adv 192.168.30.10, age 84, seq 0x80000004 (Area 1)
02:02:33: OSPF: ABR not reachable 192.168.30.10
02:02:33: OSPF: Start processing Summary LSA 192.168.10.32, mask 255.255.255.240, adv 192.168.30.10, age 84, seq 0x80000003 (Area 1)
02:02:33: OSPF: ABR not reachable 192.168.30.10
02:02:33: OSPF: Start processing Summary LSA 192.168.20.0, mask 255.255.255.252, adv 192.168.30.10, age 84, seq 0x80000004 (Area 1)
02:02:33: OSPF: ABR not reachable 192.168.30.10
02:02:33: OSPF: Start processing Summary LSA 192.168.20.2, mask 0.0.0.0, adv 192.168.30.10, age 84, seq 0x80000001 (Area 1)
02:02:33: OSPF: ABR not reachable 192.168.30.10
02:02:33: OSPF: sum_delete_old_routes area 1
02:02:33: OSPF: Started Building Type 5 External Routes
02:02:33: OSPF: ex_delete_old_routes
02:02:33: OSPF: Started Building Type 7 External Routes
02:02:33: OSPF: ex_delete_old_routes
Rub#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
U - per-user static route, o - ODR
Gateway of last resort is not set
192.168.30.0/29 is subnetted, 2 subnets
C 192.168.30.0 is directly connected, Loopback1
C 192.168.30.8 is directly connected, Serial1
172.16.0.0/24 is subnetted, 1 subnets
C 172.16.2.0 is directly connected, Ethernet0
10.0.0.0/24 is subnetted, 1 subnets
C 10.1.1.0 is directly connected, Loopback0
Rub#
02:03:05: OSPF: Detect change in LSA type 1, LSID 192.168.30.10, from 192.168.30.10 area 1
02:03:05: OSPF: Detect change in LSA type 3, LSID 192.168.20.0, from 192.168.30.10 area 1
02:03:05: OSPF: Schedule partial SPF - type 3 id 192.168.20.0 adv rtr 192.168.30.10
02:03:05: OSPF: Detect change in LSA type 3, LSID 192.168.10.32, from 192.168.30.10 area 1
02:03:05: OSPF: Schedule partial SPF - type 3 id 192.168.10.32 adv rtr 192.168.30.10
02:03:05: OSPF: Detect change in LSA type 3, LSID 192.168.10.0, from 192.168.30.10 area 1
02:03:05: OSPF: Schedule partial SPF - type 3 id 192.168.10.0 adv rtr 192.168.30.10
02:03:05: OSPF: Schedule partial SPF - type 3 id 0.0.0.0 adv rtr 192.168.30.10
02:03:05: OSPF: Service partial SPF 4/0/0
02:03:05: OSPF: Start partial processing Summary LSA 192.168.20.0, mask 255.255.255.252, adv 192.168.30.10, age 11, seq 0x80000005 (Area 1)
02:03:05: OSPF: ABR not reachable 192.168.30.10
02:03:05: OSPF: delete lsa id 192.168.20.0, type 3, adv rtr 192.168.30.10 from delete list
02:03:05: OSPF: lsa id 192.168.20.0 not on delete list
02:03:05: OSPF: Start partial processing Summary LSA 192.168.10.32, mask 255.255.255.240, adv 192.168.30.10, age 11, seq 0x80000004 (Area 1)
02:03:05: OSPF: ABR not reachable 192.168.30.10
02:03:05: OSPF: delete lsa id 192.168.10.32, type 3, adv rtr 192.168.30.10 from delete list
02:03:05: OSPF: lsa id 192.168.10.32 not on delete list
02:03:05: OSPF: Start partial processing Summary LSA 192.168.10.0, mask 255.255.255.224, adv 192.168.30.10, age 11, seq 0x80000005 (Area 1)
02:03:05: OSPF: ABR not reachable 192.168.30.10
02:03:05: OSPF: delete lsa id 192.168.10.0, type 3, adv rtr 192.168.30.10 from delete list
02:03:05: OSPF: lsa id 192.168.10.0 not on delete list
02:03:05: OSPF: Start partial processing Summary LSA 0.0.0.0, mask 0.0.0.0, adv 192.168.30.10, age 11, seq 0x80000001 (Area 1)
02:03:05: OSPF: ABR not reachable 192.168.30.10
02:03:05: OSPF: delete lsa id 0.0.0.0, type 3, adv rtr 192.168.30.10 from delete list
02:03:05: OSPF: lsa id 0.0.0.0 not on delete list
02:03:10: OSPF: running SPF for area 1
02:03:10: OSPF: Initializing to run spf
02:03:10: It is a router LSA 192.168.30.1. Link Count 3
02:03:10: Processing link 0, id 192.168.30.10, link data 192.168.30.9, type 1
02:03:10: No RTR Back link
02:03:10: Processing link 1, id 192.168.30.8, link data 255.255.255.248, type 3
02:03:10: Add better path to LSA ID 192.168.30.15, gateway 192.168.30.8, dist 64
02:03:10: Add path: next-hop 192.168.30.9, interface Serial1
02:03:10: Processing link 2, id 192.168.30.1, link data 255.255.255.255, type 3
02:03:10: Add better path to LSA ID 192.168.30.1, gateway 192.168.30.1, dist 1
02:03:10: Add path: next-hop 192.168.30.1, interface Loopback1
02:03:10: OSPF: Adding Stub nets
02:03:10: OSPF: delete lsa id 192.168.30.1, type 0, adv rtr 192.168.30.1 from delete list
02:03:10: OSPF: insert route list LS ID 192.168.30.1, type 0, adv rtr 192.168.30.1
02:03:10: OSPF: delete lsa id 192.168.30.15, type 0, adv rtr 192.168.30.1 from delete list
02:03:10: OSPF: insert route list LS ID 192.168.30.15, type 0, adv rtr 192.168.30.1
02:03:10: OSPF: Entered old delete routine
02:03:10: OSPF: running spf for summaries area 1
02:03:10: OSPF: Start processing Summary LSA 0.0.0.0, mask 0.0.0.0, adv 192.168.30.10, age 16, seq 0x80000001 (Area 1)
02:03:10: OSPF: ABR not reachable 192.168.30.10
02:03:10: OSPF: Start processing Summary LSA 192.168.10.0, mask 255.255.255.224, adv 192.168.30.10, age 16, seq 0x80000005 (Area 1)
02:03:10: OSPF: ABR not reachable 192.168.30.10
02:03:10: OSPF: Start processing Summary LSA 192.168.10.32, mask 255.255.255.240, adv 192.168.30.10, age 16, seq 0x80000004 (Area 1)
02:03:10: OSPF: ABR not reachable 192.168.30.10
02:03:10: OSPF: Start processing Summary LSA 192.168.20.0, mask 255.255.255.252, adv 192.168.30.10, age 16, seq 0x80000005 (Area 1)
02:03:10: OSPF: ABR not reachable 192.168.30.10
02:03:10: OSPF: Start processing Summary LSA 192.168.20.2, mask 0.0.0.0, adv 192.168.30.10, age 121, seq 0x80000001 (Area 1)
02:03:10: OSPF: ABR not reachable 192.168.30.10
02:03:10: OSPF: sum_delete_old_routes area 1
02:03:10: OSPF: Started Building Type 5 External Routes
02:03:10: OSPF: ex_delete_old_routes
02:03:10: OSPF: Started Building Type 7 External Routes
02:03:10: OSPF: ex_delete_old_routes
02:03:10: OSPF: Detect change in LSA type 1, LSID 192.168.30.10, from 192.168.30.10 area 1
Rub#
02:03:20: OSPF: running SPF for area 1
02:03:20: OSPF: Initializing to run spf
02:03:20: It is a router LSA 192.168.30.1. Link Count 3
02:03:20: Processing link 0, id 192.168.30.10, link data 192.168.30.9, type 1
02:03:20: Add better path to LSA ID 192.168.30.10, gateway 192.168.30.10, dist 64
02:03:20: Add path: next-hop 192.168.30.10, interface Serial1
02:03:20: Processing link 1, id 192.168.30.8, link data 255.255.255.248, type 3
02:03:20: Add better path to LSA ID 192.168.30.15, gash ip roteway 192.168.30.8, dist 64
02:03:20: Add path: next-hop 192.168.30.9, interface Serial1
02:03:20: Processing link 2, id 192.168.30.1, link data 255.255.255.255, type 3
02:03:20: Add better path to LSA ID 192.168.30.1, gateway 192.168.30.1, dist 1
02:03:20: Add path: next-hop 192.168.30.1, interface Loopback1
02:03:20: OSPF: Add Router Route to 192.168.30.10 via 192.168.30.10. Metric: 64
02:03:20: OSPF: insert route list LS ID 192.168.30.10, type 1, adv rtr 192.168.30.10
02:03:20: It is a ute
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
U - per-user static route, o - ODR
Gateway of last resort is 192.168.30.10 to network 0.0.0.0
192.168.30.0/29 is subnetted, 2router LSA 192.168.30.10. Link Count 2
02:03:20: Processing link 0, id 192.168.30.1, link data 192.168.30.10, type 1
02:03:20: Ignore newdist 128 olddist 0
02:03:20: Processing link 1, id 192.168.30.8, link data 255.255.255.248, type 3
02:03:20: Add better path to LSA ID 192.168.30.15, gateway 192.168.30.8, dist 128
02:03:20: Add path: next-hop 192.168.30.10, interface subnets
C 192.168.30.0 is directly connected, Loopback1
C 192.168.30.8 is directly connected, Serial1
192.168.10.0/24 is variably subnetted, 2 subnets, 2 masks
O IA 192.168.10.32/28 [110/202] via 192.168.30.10, 00:00:02, Serial1
O IA 192.168.10.0/27 [110/192] via 192.168.30.10, 00:00:02, Serial1
172.16.0.0/24 is subnetted, 1 subnets
C 172.16.2.0 is directly connected, Ethernet0
192.168.20.0/30 is subnetted, 1 subnets
O IA 192.168.20.0 [110/128] via 192.168.30.10, 00:00:02, Serial1
10.0.0.0/24 is subnetted, 1 subnets
C 10.1.1.0 is directly coSerial1
02:03:20: OSPF: Adding Stub nets
02:03:20: OSPF: delete lsa id 192.168.30.1, type 0, adv rtr 192.168.30.1 from delete list
02:03:20: OSPF: insert route list LS ID 192.168.30.1, type 0, adv rtr 192.168.30.1
02:03:20: OSPF: delete lsa id 192.168.30.15, type 0, adv rtr 192.168.30.1 from delete list
02:03:20: OSPF: insert route list LS ID 192.168.30.15, type 0, annected, Loopback0
O*IA 0.0.0.0/0 [110/65] via 192.168.30.10, 00:00:03, Serial1
Rub#dv rtr 192.168.30.1
02:03:20: OSPF: Entered old delete routine
02:03:20: OSPF: running spf for summaries area 1
02:03:20: OSPF: Start processing Summary LSA 0.0.0.0, mask 0.0.0.0, adv 192.168.30.10, age 26, seq 0x80000001 (Area 1)
02:03:20: Add better path to LSA ID 0.0.0.0, gateway 0.0.0.0, dist 65
02:03:20: Add path: next-hop 192.168.30.10, interface Serial1
02:03:20: Add Summary Route to 0.0.0.0. Metric: 65, Next Hop: 192.168.30.10
02:03:20: OSPF: insert route list LS ID 0.0.0.0, type 3, adv rtr 192.168.30.10
02:03:20: OSPF: Start processing Summary LSA 192.168.10.0, mask 255.255.255.224, adv 192.168.30.10, age 26, seq 0x80000005 (Area 1)
02:03:20: Add better path to LSA ID 192.168.10.0, gateway 0.0.0.0, dist 192
02:03:20: Add path: next-hop 192.168.30.10, interface Serial1
02:03:20: Add Summary Route to 192.168.10.0. Metric: 192, Next Hop: 192.168.30.10
02:03:20: OSPF: insert route list LS ID 192.168.10.0, type 3, adv rtr 192.168.30.10
02:03:20: OSPF: Start processing Summ
Rub#ary LSA 192.168.10.32, mask 255.255.255.240, adv 192.168.30.10, age 26, seq 0x80000004 (Area 1)
02:03:20: Add better path to LSA ID 192.168.10.32, gateway 0.0.0.0, dist 202
02:03:20: Add path: next-hop 192.168.30.10, interface Serial1
02:03:20: Add Summary Route to 192.168.10.32. Metric: 202, Next Hop: 192.168.30.10
02:03:20: OSPF: insert route list LS ID 192.168.10.32, type 3, adv rtr 192.168.30.10
02:03:20: OSPF: Start processing Summary LSA 192.168.20.0, mask 255.255.255.252, adv 192.168.30.10, age 26, seq 0x80000005 (Area 1)
02:03:20: Add better path to LSA ID 192.168.20.0, gateway 0.0.0.0, dist 128
02:03:20: Add path: next-hop 192.168.30.10, interface Serial1
02:03:20: Add Summary Route to 192.168.20.0. Metric: 128, Next Hop: 192.168.30.10
02:03:20: OSPF: insert route list LS ID 192.168.20.0, type 3, adv rtr 192.168.30.10
02:03:20: OSPF: Start processing Summary LSA 192.168.20.2, mask 0.0.0.0, adv 192.168.30.10, age 131, seq 0x80000001 (Area 1)
02:03:20: Add better path to LSA ID 192.168.20.2, gateway 0.0.0.0, dist 128
02:03:20: Add path: next-hop 192.168.30.10, interface Serial1
02:03:20: OSPF: Add Router Route to 192.168.20.2 from summary ASBR LSA. Metric: 128
02:03:20: OSPF: insert route list LS ID 192.168.20.2, type 4, adv rtr 192.168.30.10
02:03:20: OSPF: sum_delete_old_routes area 1
02:03:20: OSPF: Started Building Type 5 External Routes
02:03:20: OSPF: ex_delete_old_routes
02:03:20: OSPF: Started Building Type 7 External Routes
02:03:20: OSPF: ex_delete_old_routes
Rub#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
U - per-user static route, o - ODR
Gateway of last resort is 192.168.30.10 to network 0.0.0.0
192.168.30.0/29 is subnetted, 2 subnets
C 192.168.30.0 is directly connected, Loopback1
C 192.168.30.8 is directly connected, Serial1
192.168.10.0/24 is variably subnetted, 2 subnets, 2 masks
O IA 192.168.10.32/28 [110/202] via 192.168.30.10, 00:00:16, Serial1
O IA 192.168.10.0/27 [110/192] via 192.168.30.10, 00:00:16, Serial1
172.16.0.0/24 is subnetted, 1 subnets
C 172.16.2.0 is directly connected, Ethernet0
192.168.20.0/30 is subnetted, 1 subnets
O IA 192.168.20.0 [110/128] via 192.168.30.10, 00:00:16, Serial1
10.0.0.0/24 is subnetted, 1 subnets
C 10.1.1.0 is directly connected, Loopback0
O*IA 0.0.0.0/0 [110/65] via 192.168.30.10, 00:00:17, Serial1
Rub#u all
All possible debugging has been turned off
Rub#
Lần này sẽ nói về Operation của OSPF.
Thiết lập neighbor:
Ban đầu, khi router bắt đầu chạy OSPF thì nó sẽ gửi Hello packet ra tất cả các interface nào được enable OSPF trên đó. Lúc đó các router kế cận nó (connected) sẽ nhận được những packet này, và xem xét tất cả những field có trong packet để rút ra kết luận có thể thiết lập neighbor được hay không? Trong packet này sẽ có các field quan trọng như: Area ID, hello/dead interval, DR, password trên interface đó và một bit N/P cho biết router area này thuộc loại nào.
Thiết lậ p adjacencies:
Sau khi đã trở thành neighbor với nhau thì tuỳ theo kiểu interface kết nối mà 2 router sẽ quyết định xem có thiết lập adjacencies không:
*Point-to-point: (******, leased line) đối với kiểu interface này thì chỉ có 2 router nối trực tiếp với nhau, do đó adjacencies sẽ được thiết lập.
*Broadcast(Ethernet, TokenRing, FDDI) do có nhiều Router cùng chia sẽ một link kết nối, như vậy sẽ xảy ra trường hợp trên một link physical mà có rất nhiều link logical.Và ứng với mỗi link logical đó, thì sẽ có bấy nhiêu LSA packet được gửi đi. Chúng ta hãy làm thử một phép tính nhỏ: nếu mạng Ethernet có 10 router nối với nhau, mỗi router sẽ thiết lập adjacencies đến 9 router còn lại thì sẽ có 10*9/2 = 45 adjacencies/link. Do đó, trong trường hợp này, trong mạng sẽ chọn ra 1 router là Designated Router(DR) thiết lập adjacencies đến các router còn lại trong mạng để lắng nghe tất cả các Link-State information (nghĩa là router có update, thì A chỉ send đến DR,BDR rồi DR mới send lại cho các router khác). Ngoài ra còn 1 router nữa sẽ làm BakupDR(BDR), BDR cũng thiết lập adjacencies đến tất cả những router còn lại (cả DR) để khi DR bị down, BDR sẽ lên thế chỗ không làm mạng bị gián đoạn.
bầu chọn DR,BDR: thì Cisco router sẽ lựa chọn theo các tiêu chí sau theo thứ tự tính ưu tiên giảm dần:
+ Priority: cấp độ ưu tiên của mỗi router, priority nào cao hơn thì sẽ được chọn.
+ Router ID: càng cao thì sẽ được chọn
Một chú ý nho nhỏ là việc bầu chọn này chỉ diễn ra ở giai đoạn 2-way. Nên khi có một router trong mạng được sửa priority là 255 (maximum) thì DR và BDR vẫn không thay đổi. Khi làm lab, bạn có thể sử dụng lệnh [/b]clear ip ospf process trên DR và BDR và show ip ospf neighbor để xem DR và BDR thay đổi thế nào.
*[B]Non-Broadcast Multi Access(NBMA): (Frame-relay, X25…) thì cũng tương tự như Broadcast, network sẽ bầu chọn lên DR và BDR thiết lập adjacencies đến tất cả những router còn lại trong mạng.
Trao đổi LSA:
Như bài trước Liwh đã nói LSA là thứ mà OSPF dùng để tính toán nên bảng routing table. OSPF đã cung cấp 2 địa chỉ multicast là 224.0.0.6 cho DR,BDR và 224.0.0.5 cho các router còn lại (DROther) chạy OSPF trong mạng. Ngoài ra còn có một kĩ thuật gọi là flooding, dành cho việc trao đổi các LSA packet giữa các router có thiết lập adjacencies với nhau.
Ban đầu, khi thiết lập xong adjacencies, thì 2 router thiết lập adjacencies sẽ tiếp tục bình chọn Master/Slave. Master sẽ là người điều khiển việc trao đổi các LSA packet ban đầu với nhau hay còn gọi là Database Description( DD) để đồng bộ LSDatabase. DD thực chất chỉ là các LSA header, để giúp cho 2 router có cái nhìn cơ bản về mạng hiện thời (quan trọng nhất ở đây chỉ là sao cho 2 LSDatabase có các LS entry giống nhau).
Sau khi việc đồng bộ hoá đã hoàn tất, 2 router sẽ đến phần lấy chi tiết các LS entry mà mình chỉ có phần header không thôi. Tức là khi Router A gửi 1 DD cho B nói là mình có 1 entry về mạng 172.16.2.0, entry này trong B không có. Lúc này B sẽ gửi 1 LSRequest, yêu cầu A gửi thông tin chi tiết về entry 172.16.2.0 mà B yêu cầu như netmask, các Router có trong mạng đó.
Đến lúc này, các router đã có đủ thông tin để tạo nên bảng routing table của riêng mình.
Ta nói về Flooding:
*Point-to-point: thì khi có update, một router (bắt nguồn update) trong mạng sẽ gửi 1 LSUpdate packet đến router còn lại theo địa chỉ 224.0.0.5 (AllSPF).
*Broadcast: giả sử network có update là stub của một DROther, lúc này, một LSUpdate sẽ được gửi theo địa chỉ 224.0.0.6 đến DR và BDR. Lúc này, DR và BDR sẽ chuyển ngược lại cho DROther theo địa chỉ 224.0.0.5. Như vậy, toàn bộ router trong mạng sẽ nhận được LSUpdate.
*NBMA:tương tự như Broadcast, nhưng các update sẽ được gửi theo kiểu unicast. Tức là gửi trực tiếp địa chỉ DR,BDR; còn DR thì gửi nhiều bản đến từng router riêng biệt.
Sau đó các router sẽ gửi LSUpdate ra tất cả các interface còn lại của mình.
Theo lí thuyết thì từ khi active OSPF đến khi hoàn tất bản LSDatabase thì router sẽ trải qua 6 bước:
Init: send Hello (có cả các neighbor trong mạng)
2-way: nhận được Hello thiết lập kết nối chiều khi nhận thấy có RouterId của mình trong neighbor field của Hello, bầu chọn ra DR và BDR (nếu là Broadcast hay NBMA).
ExStart: bầu chọn Master/Slave
ExChange: trao đổi DD với nhau
Load: gửi chi tiết về các LS entry nhận từ neighbor mà router không có.
Full: hoàn tất việc thiết lập Adjacencies.
To blackdot: bạn có case nào hay không, send cho mình với. Thanks
Liwh đã không lên đây viết bài rất lâu, nhưng đây là mùa thi nên mình có nhiều bài vở để học. Mong các bạn thông cảm, hy vọng đến hết tháng 2 thì Liwh sẽ rảnh rang hơn. Nếu cần hãy liên hệ với Liwh ở hộp mail Lord_TAM@yahoo.com hay gọi 8995715 cũng được, hộp mail kia Liwh mất pass rùi .
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