Routing Table路由表

• Directly connected networks直接連接的網路
• Dynamic routes動態路由
• Static routes靜態路由
• Default routes預設路由

• Route source: Identifies how the route was learned. Directly connected interfaces have two route source codes. "C" identifies a directly connected network. "L" identifies the local IPv4 address assigned to the router’s interface.路由來源：標示該路由是如何被學習到的。直接連接介面有兩種路由來源代碼。「C」代表直接連接的網路。「L」代表指定給路由器介面的本地 IPv4 位址。
• Destination network: For directly connected networks, the destination networks are local to the router. The destination network address is indicated with a network address and subnet mask in the form of the prefix. Note that "L" entries, which identify the local IPv4 address of the interface, have a prefix of /32.目的網路：對直接連接的網路而言，目的網路就是路由器本身所在的本地網路。目的網路位址以網路位址與前綴形式的子網路遮罩表示。請注意，代表介面本地 IPv4 位址的「L」項目，前綴為 /32。
• Outgoing interface: Identifies the exit interface to use when forwarding packets to the destination network.出口介面：標示轉送封包到目的網路時要使用的出口介面。

• Route source: Identifies how the route was learned. "O" in the figure indicates that the source of the entry was the OSPF dynamic routing protocol.路由來源：標示該路由是如何被學習到的。圖中的「O」表示該項目的來源是 OSPF 動態路由協定。
• Destination network: Identifies the address of the remote network. The router knows how to reach 172.16.1.0/24 network.目的網路：標示遠端網路的位址。路由器知道如何到達 172.16.1.0/24 網路。
• Administrative distance: Identifies the trustworthiness of the route source. Lower values indicate the preferred route source. OSPF has a default administrative distance value of 110.管理距離：標示路由來源的可信度。數值越低，表示越優先採用的路由來源。OSPF 預設的管理距離值為 110。
• Metric: Identifies the value assigned to reach the remote network. Lower values indicate preferred routes. This OSPF route has a metric of 2 for the destination network 172.16.1.0/24.度量值：標示到達遠端網路所指定的數值。數值越低，表示越優先的路由。此 OSPF 路由到目的網路 172.16.1.0/24 的度量值為 2。
• Next-hop: Identifies the IPv4 address of the next router to forward the packet to. The IPv4 address of the next-hop is 192.168.10.2.下一跳：標示要轉送封包的下一個路由器的 IPv4 位址。此下一跳的 IPv4 位址為 192.168.10.2。
• Route time stamp: Identifies how much time has passed since the route was learned. The information in the example entry was learned 3 minutes and 23 seconds ago.路由時間戳記：標示自學習到此路由以來經過的時間。範例項目中的資訊是在 3 分 23 秒前學習到的。
• Outgoing interface: Identifies the exit interface to use to forward a packet toward the final destination. The packets destined to the 172.16.1.0/24 network will be forwarded out of the GigabitEthernet 0/1 interface.出口介面：標示轉送封包到最終目的地時要使用的出口介面。目的地為 172.16.1.0/24 網路的封包會經由 GigabitEthernet 0/1 介面轉送出去。

• Route source: Identifies how the route was learned. Static routes have a route source code "S".路由來源：標示該路由是如何被學習到的。靜態路由的路由來源代碼為「S」。
• Destination network: The destination network address is indicated with a network address and subnet mask in the prefix. The router knows how to reach 192.168.30.0/24 network.目的網路：目的網路位址以網路位址與前綴形式的子網路遮罩表示。路由器知道如何到達 192.168.30.0/24 網路。
• Administrative distance: Identifies the trustworthiness of the route source. Lower values indicate the preferred route source. Static routes have a default administrative value of 1.管理距離：標示路由來源的可信度。數值越低，表示越優先採用的路由來源。靜態路由預設的管理距離值為 1。
• Metric: Identifies the value assigned to reach the remote network. Static routes do not calculate metrics the same way as dynamic routes; metric is set. The default value for the metric of a static route is 0.度量值：標示到達遠端網路所指定的數值。靜態路由的度量值計算方式與動態路由不同，其度量值是固定設定的。靜態路由度量值的預設值為 0。
• Next-hop:Identifies the IPv4 address of the next router to forward the packet to. The IPv4 address of the next-hop is 192.168.10.2.下一跳：標示要轉送封包的下一個路由器的 IPv4 位址。此下一跳的 IPv4 位址為 192.168.10.2。

• Route source: Identifies how the route was learned. The default route is marked with an asterisk (*). Depending on the source of a default route, an asterisk is added to the route source (S* in the example.)路由來源：標示該路由是如何被學習到的。預設路由會以星號（*）標示。依據預設路由的來源不同，星號會加在路由來源代碼上（範例中為 S*）。
• Destination network: The destination network for the default route is 0.0.0.0/0.目的網路：預設路由的目的網路為 0.0.0.0/0。
• Administrative distance: Identifies the trustworthiness of the route source. Lower values indicate the preferred route source. The default route has the same administrative distance as a source of a default route. In the example, the default route's source is a static route, with a default administrative distance value of 1.管理距離：標示路由來源的可信度。數值越低，表示越優先採用的路由來源。預設路由的管理距離與提供該預設路由的來源相同。在此範例中，預設路由的來源是靜態路由，其預設管理距離值為 1。
• Metric: Identifies the value assigned to reach the remote network. The default route inherits the metric value from the route source. In the example, since the default route is statically configured, the metric is 0.度量值：標示到達遠端網路所指定的數值。預設路由會繼承其路由來源的度量值。在此範例中，由於預設路由是靜態設定的，度量值為 0。
• Next-hop:Identifies the IPv4 address of the next router to forward the packet to. The IPv4 address of the next-hop for the default route in the example is 10.1.1.1.下一跳：標示要轉送封包的下一個路由器的 IPv4 位址。範例中預設路由的下一跳 IPv4 位址為 10.1.1.1。

RouterA# show ip route
Codes: L - local, C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, + - replicated route

Gateway of last resort is 10.1.1.1 to network 0.0.0.0

C 10.1.1.0/24 is directly connected, GigabitEthernet0/0
L 10.1.1.2/32 is directly connected, GigabitEthernet0/0
R 172.16.0.0/16 [120/1] via 192.168.10.2, 00:01:08, GigabitEthernet0/1
O 172.16.1.0/24 [110/2] via 192.168.10.2, 00:03:23, GigabitEthernet0/1
D 192.168.20.0/24 [90/156160] via 10.1.1.1, 00:01:23, GigabitEthernet0/0
S 192.168.30.0/24 [1/0] via 192.168.10.2
C 192.168.10.0/24 is directly connected, GigabitEthernet0/1
L 192.168.10.1/32 is directly connected, GigabitEthernet0/1
S* 0.0.0.0/0 [1/0] via 10.1.1.1

• C: Indicates directly connected networks; the first and seventh entries are directly connected networks.C：表示直接連接的網路；第一與第七筆項目為直接連接的網路。
• L: Indicates local interfaces within connected networks; the second and eighth entries are local interfaces.L：表示連接網路內的本地介面；第二與第八筆項目為本地介面。
• R: Indicates RIP; the third entry is the RIP route.R：表示 RIP；第三筆項目為 RIP 路由。
• O: Indicates OSPF; the fourth entry is an OSPF route.O：表示 OSPF；第四筆項目為 OSPF 路由。
• D: Indicates EIGRP; the fifth entry is an EIGRP route. The letter D stands for Diffusing Update Algorithm (DUAL), which is the update algorithm that EIGRP uses. The code letter E was previously taken by the legacy Exterior Gateway Protocol (EGP).D：表示 EIGRP；第五筆項目為 EIGRP 路由。字母 D 代表 EIGRP 所使用的更新演算法「擴散更新演算法」（Diffusing Update Algorithm，DUAL）。字母 E 先前已被舊式的外部閘道協定（Exterior Gateway Protocol，EGP）使用。
• S: Indicates static routes; the sixth and ninth entries are static routes.S：表示靜態路由；第六與第九筆項目為靜態路由。
• Asterisk (*): Indicates that this static route is a candidate for the default route.星號（*）：表示此靜態路由是預設路由的候選項目。