# 5类LSA ：外部路由前缀 + ASBR的router_id IOU5#sh ip ospf data extOSPF Router with ID (5.5.5.5) (Process ID 1)Type-5 AS External Link StatesLS age: 71Options: (No TOS-capability, DC, Upward)LS Type: AS External LinkLink State ID: 10.1.55.0 (External Network Number )Advertising Router: 5.5.5.5LS Seq Number: 80000002Checksum: 0x61E7Length: 36Network Mask: /24Metric Type: 2 (Larger than any link state path)MTID: 0 Metric: 20 # 种子metricForward Address: 0.0.0.0External Route Tag: 0# 区域内路由OE T5 + T1/T2 IOU4# sh ip ospf data OSPF Router with ID (4.4.4.4) (Process ID 1)Router Link States (Area 0) Link ID ADV Router Age Seq# Checksum Link count 2.2.2.2 2.2.2.2 1 (DNA) 0x80000005 0x00EBE8 1 3.3.3.3 3.3.3.3 1 (DNA) 0x80000005 0x00AD1E 1 4.4.4.4 4.4.4.4 294 0x80000006 0x00F05A 4 5.5.5.5 5.5.5.5 211 0x80000004 0x006863 3Type-5 AS External Link States Link ID ADV Router Age Seq# Checksum Tag 10.1.55.0 5.5.5.5 211 0x80000003 0x005FE8 0IOU4#sh ip ro 10.1.55.55 Routing entry for 10.1.55.0/24Known via "ospf 1", distance 110, metric 20, type extern 2, forward metric 64Last update from 10.1.45.5 on Serial2/1, 01:15:51 agoRouting Descriptor Blocks:* 10.1.45.5, from 5.5.5.5, 01:15:51 ago, via Serial2/1Route metric is 20, traffic share count is 1
# 4类LSA： ASBR的router_id + 本区域ABR的router_id IOU1#sh ip ospf da asbr-summary OSPF Router with ID (1.1.1.1) (Process ID 1)Summary ASB Link States (Area 2)Routing Bit Set on this LSA in topology Base with MTID 0LS age: 840Options: (No TOS-capability, DC, Upward)LS Type: Summary Links(AS Boundary Router)Link State ID: 5.5.5.5 (AS Boundary Router address)Advertising Router: 2.2.2.2LS Seq Number: 80000003Checksum: 0x5944Length: 28Network Mask: /0MTID: 0 Metric: 128 Routing Bit Set on this LSA in topology Base with MTID 0LS age: 814Options: (No TOS-capability, DC, Upward)LS Type: Summary Links(AS Boundary Router)Link State ID: 5.5.5.5 (AS Boundary Router address)Advertising Router: 3.3.3.3LS Seq Number: 80000003Checksum: 0x3B5ELength: 28Network Mask: /0MTID: 0 Metric: 128 # 域间路由： T5 + T4 + T1/T2 IOU1#sh ip ospf da OSPF Router with ID (1.1.1.1) (Process ID 1)Router Link States (Area 2) Link ID ADV Router Age Seq# Checksum Link count 1.1.1.1 1.1.1.1 751 0x80000004 0x00E906 2 2.2.2.2 2.2.2.2 783 0x80000007 0x008C74 1 3.3.3.3 3.3.3.3 756 0x80000007 0x004EA9 1Summary ASB Link States (Area 2) Link ID ADV Router Age Seq# Checksum 5.5.5.5 2.2.2.2 783 0x80000003 0x005944 5.5.5.5 3.3.3.3 756 0x80000003 0x003B5EType-5 AS External Link States Link ID ADV Router Age Seq# Checksum Tag 10.1.55.0 5.5.5.5 727 0x80000003 0x005FE8 0
# 5类LSA的外部路由OE2选择： # 1、外部路由的metric小优先 IOU1(config-router)#redistribute connected route-map loop metric 10 IOU4# sh ip ro O E2 10.1.55.0/24 [110/10] via 10.1.234.3, 00:00:03, Serial2/0[110/10] via 10.1.234.2, 00:00:03, Serial2/0 IOU4#sh ip ro 10.1.55.55 Routing entry for 10.1.55.0/24Known via "ospf 1", distance 110, metric 10, type extern 2, forward metric 74Last update from 10.1.234.2 on Serial2/0, 00:04:44 agoRouting Descriptor Blocks:* 10.1.234.3, from 1.1.1.1, 00:04:44 ago, via Serial2/0Route metric is 10, traffic share count is 110.1.234.2, from 1.1.1.1, 00:04:44 ago, via Serial2/0Route metric is 10, traffic share count is 1# 2、外部路由的metric相等，forward metric小优先； IOU1(config-router)#redistribute connected route-map loop metric 20IOU4# sh ip ro
转载于:https://blog.51cto.com/f1yinsky/2044175
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