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本文件說明中繼系統對中繼系統 (IS-IS) 通訊協定相鄰和區域類型。
本文件所述內容不限於特定軟體和硬體版本。
本文中的資訊是根據特定實驗室環境內的裝置所建立。文中使用到的所有裝置皆從已清除(預設)的組態來啟動。如果您的網路運作中,請確保您瞭解任何指令可能造成的影響。
IS-IS協定被廣泛用作網際網路服務提供商(ISP)環境中的內部網關協定(IGP)。本文檔的範圍是提供有關IS-IS區域型別、配置和故障排除的資訊。文中提供一個範例網路情境及其組態,並附上一些偵錯、擷取和輸出,加深瞭解。
在本文檔中,IS-IS表示整合IS-IS。整合IS-IS部署,這意味著IS-IS是路由網際網路協定(IP)。 IS-IS的真正力量在於它使用型別長度值(TLV),使得IS-IS協定具有高度可擴充性。 隨著新功能的引入,它們可以增加到TLV的協定中。
在OSPF協定中,任何路由器的介面都可以分配給特定區域。但是,IS-IS中的區域概念不同。一般來說,此處每個路由器都屬於一個區域。
這種想法源於最初建立的IS-IS,用於路由無連線網路協定(CLNP),其中地址屬於裝置(路由器),而在網際網路協定(IP)中,地址屬於特定介面。
IS-IS協定有兩個級別或層次結構:級別1和級別2。
級別1對應於OSPF區域內路由,而級別2對應於OSPF主幹區域0路由。
2級區域將所有區域與主幹區域連線起來。
預設情況下,每個Cisco路由器都作為1-2級(L1/L2)路由器提供。
1級路由器可能會與1級和1-2級(L1/L2)路由器相鄰。
第2級路由器可能與第2級路由器或第1-2級(L1/L2)路由器相鄰。
僅L1路由器與僅L2路由器之間沒有鄰接關係。
IS-IS第1級路由器擁有其自己區域內所有區域內拓撲的鏈路狀態資訊。為了將資料包路由到其他區域,它使用最接近的Level 2 capable (L1/L2)路由器。 第1級區域的行為與OSPF完全末節區域非常相似。L1是傳送L1 Hello的唯一路由器。
IS-IS L1/L2路由器維護兩個鏈路狀態資料庫資訊。
一個用於級別1,另一個用於級別2。
運行兩個不同的「最短路徑優先」(SPF)計算;一個在第1級鏈路狀態資料庫中,另一個在第2級鏈路狀態資料庫中。
IS-IS第1-2級路由器的行為與OSPF區域邊界路由器(ABR)非常接近。L1/L2路由器傳送L1和L2 Hello資料包。
預設情況下,L1/L2路由器允許字首從L1區域單向傳遞到L2區域,但不允許反向傳遞。
但是,如果需要將字首從L2區域移動到L1區域,則需要IS-IS配置下的redistribute命令。
IS-IS第2級路由器具有區域內和區域間路由的鏈路狀態資訊。
L2路由器僅傳送L2 Hello。IS-IS第2級區域可與OSPF主幹區域0進行比較。
IS-IS鄰接表
路由器型別 |
L1 |
L1/L2 |
L2 |
L1 |
L1鄰接(如果區域ID匹配),否則無鄰接 |
L1鄰接(如果區域ID匹配),否則無鄰接 |
無鄰接 |
L1/L2 |
L1鄰接(如果區域ID匹配),否則無鄰接 |
L1和L2鄰接(如果區域ID匹配),否則,僅L2鄰接 |
L2鄰接,區域ID不重要 |
L2 |
無鄰接 |
L2鄰接,區域ID不重要 |
L2鄰接,區域ID不重要 |
MTU |
如果某個IS-IS路由器收到的ISIS hello資料包的MTU高於其可支援的MTU(在介面上),它會丟棄Hello,因此鄰接關係不會出現。在最佳實踐中,兩端的MTU必須相同。 |
電路型別 |
此屬性是在介面上配置的,用於定義什麼型別的hello,即特定介面上傳送L1或L2。 L1/L2路由器可以選擇性地在一個介面上傳送L1僅hello資料包,而在另一個介面上傳送L2僅hello資料包。 如果L1/L2路由器嘗試與僅L1路由器對等且L1/L2介面配置了isis circuit-type level-2,則它僅向介面傳送L2 hello消息,且與L1路由器的鄰接關係未出現。 路由器必須傳送相容型別的hello。 |
驗證 |
IS-IS可以單獨驗證Hello和鏈路狀態協定資料單元(LSP)。如果Hello身份驗證正確,並且LSP身份驗證失敗,則鄰接關係啟動,但更新不會交換。 如果為IS-IS hello或PDU(協定資料單元)配置了身份驗證,則身份驗證的兩端必須匹配。 |
功能TLV |
如果IS-IS路由器不支援來自另一個IS-IS路由器的功能TLV,則它會靜默地忽略TLV。 但是,當一台路由器到達INIT狀態時,由於功能不匹配,會發生一些事件,而另一台路由器丟棄資料包且不形成鄰接關係。 作為一般建議,功能TLV必須匹配才能成功形成鄰接關係。有關功能TLV詳細資訊的討論不在本檔案的範圍之內。 |
網路型別 |
IS-IS中有兩種網路型別:廣播和點對點。廣播是預設網路型別。 如果一端配置了isis網路點對點,而另一端是預設網路型別,則系統會丟棄hello資料包,不會出現鄰接關係。 兩端的網路型別必須匹配。 |
海洛 |
Hello計時器無需匹配即可啟動鄰接關係。 |
IS-IS中只有三種鄰接狀態。
子網屬於192.168.X.0型別,其中X顯示在圖中的介面之間。
環回型別為192.168.YY.YY,其中Y為1,而Router為R1。因此,對於R1環回,ip是192.168.11.11。
L1、L1/L2和L2分別為1級、1-2級和2級路由器。
IS-IS協定需要在介面級別和全局級別進行配置。
!
interface Loopback1
ip address 192.168.11.11 255.255.255.255
ip router isis 1
!
interface FastEthernet0/0
ip address 192.168.1.1 255.255.255.0
ip router isis 1
interface FastEthernet1/0
ip address 192.168.2.1 255.255.255.0
ip router isis 1
!
router isis 1
net 49.0000.0000.0001.00
is-type level-1
!
!
interface Loopback1
ip address 192.168.22.22 255.255.255.255
ip router isis 1
!
interface FastEthernet0/0
ip address 192.168.1.2 255.255.255.0
ip router isis 1
interface FastEthernet1/0
ip address 192.168.3.2 255.255.255.0
ip router isis 1
!
router isis 1
net 49.0000.0000.0002.00
is-type level-1
!
!
interface Loopback1
ip address 192.168.33.33 255.255.255.255
ip router isis 1
!
interface FastEthernet0/0
ip address 192.168.2.3 255.255.255.0
ip router isis 1
interface FastEthernet1/0
ip address 192.168.4.3 255.255.255.0
ip router isis 1
!
router isis 1
net 49.0000.0000.0003.00
is-type level-1
!
!
interface Loopback1
ip address 192.168.44.44 255.255.255.255
ip router isis 1
!
interface FastEthernet0/0
ip address 192.168.3.4 255.255.255.0
ip router isis 1
!
interface FastEthernet1/0
ip address 192.168.4.4 255.255.255.0
ip router isis 1
!
interface FastEthernet1/1
ip address 192.168.5.4 255.255.255.0
ip router isis 1
!
interface FastEthernet2/0
ip address 192.168.6.4 255.255.255.0
ip router isis 1
!
router isis 1
net 49.0000.0000.0004.00
!
!
interface Loopback1
ip address 192.168.55.55 255.255.255.255
ip router isis 1
!
interface FastEthernet0/0
ip address 192.168.5.5 255.255.255.0
ip router isis 1
!
interface FastEthernet1/0
ip address 192.168.7.5 255.255.255.0
ip router isis 1
!
router isis 1
net 50.0000.0000.0005.00
is-type level-2-only
!
!
interface Loopback1
ip address 192.168.66.66 255.255.255.255
ip router isis 1
!
interface FastEthernet0/0
ip address 192.168.6.6 255.255.255.0
ip router isis 1
!
interface FastEthernet1/0
ip address 192.168.8.6 255.255.255.0
ip router isis 1
!
router isis 1
net 50.0000.0000.0006.00
is-type level-2-only
!
!
interface Loopback1
ip address 192.168.77.77 255.255.255.255
ip router isis 1
!
interface FastEthernet0/0
ip address 192.168.7.7 255.255.255.0
ip router isis 1
!
interface FastEthernet1/0
ip address 192.168.8.7 255.255.255.0
ip router isis 1
!
router isis 1
net 50.0000.0000.0007.00
is-type level-2-only
!
R1和R2中的區域ID相同。這兩台都是1級路由器。 它們之間存在L1鄰接。
R1#show isis neighbors
Tag 1:
System Id Type Interface IP Address State Holdtime Circuit Id
R2 L1 Fa0/0 192.168.1.2 UP 7 R2.01
由於R1和R2都是L1路由器並且屬於同一區域,因此R1和R2之間的LAN網段上僅提供L1型別的IS-IS hello。
R1#debug isis adj-packets fastEthernet 0/0
*Nov 25 19:25:53.995: ISIS-Adj: Sending L1 LAN IIH on FastEthernet0/0, length 1497
*Nov 25 19:25:54.071: ISIS-Adj: Rec L1 IIH from ca02.1c80.0000 (FastEthernet0/0), cir type L1, cir id 0000.0000.0002.01, length 1497
-- The highlighted portion shows the Mac Address and the circuit id of R2, it also shows that L1 IS-IS hello packet was received from R2 --
*Nov 25 19:25:54.075: ISIS-Adj: New adjacency, level 1 for ca02.1c80.0000
-- The above line shows that R1 has discovered a new neighbour capable of L1 adjacency, having the mac address ca02.1c80.0000 R2 --
*Nov 25 19:25:54.991: ISIS-Adj: Sending L1 LAN IIH on FastEthernet0/0, length 1497
*Nov 25 19:25:55.047: ISIS-Adj: Rec L1 IIH from ca02.1c80.0000 (FastEthernet0/0), cir type L1, cir id 0000.0000.0002.01, length 1497
*Nov 25 19:25:55.051: ISIS-Adj: L1 adj count 1
*Nov 25 19:25:55.055: ISIS-Adj: L1 adjacency state goes to Up
-- Once both the routers mutually agree on interface settings and other global parameters (e.g. authentication, circuit-type, mtu etc.) the L1 adjacency finally comes up --
ISIS HELLO
.... ..01 = Circuit type: Level 1 only (0x01) >>> Circuit type is Level 1
0000 00.. = Reserved: 0x00
SystemID {Sender of PDU}: 0000.0000.0002 >>> Identification of R2
Holding timer: 10 >>> Hold timer for hellos
PDU length: 1497 >>> Entire PDU in bytes
.100 0000 = Priority: 64 >>> Default Priority for DR election
0... .... = Reserved: 0
SystemID {Designated IS}: 0000.0000.0002.01 >>> SystemID + Pseudonode ID
Protocols Supported (1)
NLPID(s): IP (0xcc) >>> IS-IS is routing IP
Area address(es) (2)
Area address (1): 49 >>> Area id of R2
IP Interface address(es) (4)
IPv4 interface address: 192.168.1.2 (192.168.1.2) >>> IP of R2’s fa0/0
Restart Signaling (3)
Restart Signaling Flags: 0x00
.... .0.. = Suppress Adjacency: False
.... ..0. = Restart Acknowledgment: False
.... ...0 = Restart Request: False
IS Neighbor(s) (6)
IS Neighbor: ca:01:1d:a4:00:00 (ca:01:1d:a4:00:00) >>> Mac of R2 ( fa0/0 )
Padding (255)
Padding (255)
Padding (255)
Padding (255)
Padding (255)
Padding (157)
ISIS HELLO
.... ..01 = Circuit type: Level 1 only (0x01) >>> Circuit type is Level 1
0000 00.. = Reserved: 0x00
SystemID {Sender of PDU}: 0000.0000.0001 >>> Identification of R1
Holding timer: 30 >>> Hold time for hellos
PDU length: 1497 >>> Entire PDU in bytes
.100 0000 = Priority: 64 >>> Default Priority for DR election
0... .... = Reserved: 0
SystemID {Designated IS}: 0000.0000.0001.01 >>> SystemID + Pseudonode Id
Protocols Supported (1)
NLPID(s): IP (0xcc) >>> IS-IS is routing IP
Area address(es) (2)
Area address (1): 49 >>> Area id of R1
IP Interface address(es) (4)
IPv4 interface address: 192.168.1.1 (192.168.1.1) >>> IP of R1 fa0/0 interface
Restart Signaling (3)
Restart Signaling Flags: 0x00
.... .0.. = Suppress Adjacency: False
.... ..0. = Restart Acknowledgment: False
.... ...0 = Restart Request: False
IS Neighbor(s) (6)
IS Neighbor: ca:02:1c:80:00:00 (ca:02:1c:80:00:00)>>> Mac of R1 fa0/0 interface
Padding (255)
Padding (255)
Padding (255)
Padding (255)
Padding (255)
Padding (157)
Cisco IOS®實施了一種機制,用於在建立鄰接之前檢測介面上的MTU。
建立鄰接關係後,不會由於MTU問題發生資料包丟棄,因此可以防止資料庫損壞。
填充IS-IS Hello會增加其大小,直到介面的MTU為止,並且觀察另一端是否可以接受具有此MTU的Hello資料包。
如果在另一端有較低的MTU退出,則該端會丟棄Hello,因此鄰接關係不會出現。
在IS-IS中,廣播LAN網段中的DR始終傳送正常hello時間的三分之一(即10秒)的hello。 從DR的角度來看,Hello時間為3.33秒,保持時間為10秒。在之前的捕獲示例中,R2是DR。這也可以從下面的輸出進行驗證。
R2#sh clns interface fastEthernet 0/0
FastEthernet0/0 is up, line protocol is up
Checksums enabled, MTU 1497, Encapsulation SAP
ERPDUs enabled, min. interval 10 msec.
CLNS fast switching enabled
CLNS SSE switching disabled
DEC compatibility mode OFF for this interface
Next ESH/ISH in 31 seconds
Routing Protocol: IS-IS
Circuit Type: level-1-2
Interface number 0x1, local circuit ID 0x1
Level-1 Metric: 10, Priority: 64, Circuit ID: R2.01
DR ID: R2.01
Level-1 IPv6 Metric: 10
Number of active level-1 adjacencies: 1
Next IS-IS LAN Level-1 Hello in 1 seconds
R2和R4之間的區域ID相同。R2為級別1,R4為級別1-2。
由於R4是L1/L2路由器,因此它同時傳送L1和L2 hello(如前所述)。
R2是L1唯一路由器,區域ID相同,因此形成L1鄰接。
R2#show isis neighbors
Tag 1:
System Id Type Interface IP Address State Holdtime Circuit Id
R4 L1 Fa1/0 192.168.3.4 UP 8 R4.01
*Nov 26 03:56:25.299: ISIS-Adj: Sending L1 LAN IIH on FastEthernet1/0, length 1497
*Nov 26 03:56:25.355: ISIS-Adj: Rec L1 IIH from ca04.0cf4.0000 (FastEthernet1/0), cir type L1L2, cir id 0000.0000.0004.01, length 1497
*Nov 26 03:56:25.355: ISIS-Adj: New adjacency, level 1 for ca04.0cf4.0000
*Nov 26 03:56:26.299: ISIS-Adj: Sending L1 LAN IIH on FastEthernet1/0, length 1497
*Nov 26 03:56:26.339: ISIS-Adj: Rec L1 IIH from ca04.0cf4.0000 (FastEthernet1/0), cir type L1L2, cir id 0000.0000.0004.01, length 1497
*Nov 26 03:56:26.343: ISIS-Adj: L1 adj count 1
*Nov 26 03:56:26.343: ISIS-Adj: L1 adjacency state goes to Up
*Nov 26 03:56:26.347: ISIS-Adj: Run level-1 DR election for FastEthernet1/0
*Nov 26 03:56:26.351: ISIS-Adj: New level-1 DR 0000.0000.0004 on FastEthernet1/0
*Nov 26 03:56:26.467: ISIS-Adj: Rec L2 IIH from ca04.0cf4.0000 (FastEthernet1/0), cir type L1L2, cir id 0000.0000.0004.01, length 1497
*Nov 26 03:56:26.471: ISIS-Adj: is-type mismatch
-- The above line in output is due to the fact that R2 is L1 only and hence does not understand the L2 hellos from the L1/L2 Router R2 --
ISO 10589 ISIS InTRA Domain Routing Information Exchange Protocol
Intra Domain Routing Protocol Discriminator: ISIS (0x83)
PDU Header Length: 27
Version: 1
System ID Length: 0
...1 0000 = PDU Type: L2 HELLO (16)
000. ... = Reserved: 0x00
Version2 (==1): 1
Reserved (==0): 0
Max.AREAs: (0==3): 0
ISIS HELLO
.... ..11 = Circuit type: Level 1 and 2 (0x03)
0000 00.. = Reserved: 0x00
SystemID {Sender of PDU}: 0000.0000.0004
Holding timer: 30
PDU length: 1497
.100 0000 = Priority: 64
0... .... = Reserved: 0
SystemID {Designated IS}: 0000.0000.0004.01
Protocols Supported (1)
NLPID(s): IP (0xcc)
Area address(es) (2)
Area address (1): 49
IP Interface address(es) (4)
IPv4 interface address: 192.168.3.4 (192.168.3.4)
Restart Signaling (3)
Restart Signaling Flags: 0x00
.... .0.. = Suppress Adjacency: False
.... ..0. = Restart Acknowledgment: False
.... ...0 = Restart Request: False
Padding (255)
Padding (255)
Padding (255)
Padding (255)
Padding (255)
Padding (165)
ISO 10589 ISIS InTRA Domain Routing Information Exchange Protocol
Intra Domain Routing Protocol Discriminator: ISIS (0x83)
PDU Header Length: 27
Version: 1
System ID Length: 0
...0 1111 = PDU Type: L1 HELLO (15)
000. .... = Reserved: 0x00
Version2 (==1): 1
Reserved (==0): 0
Max.AREAs: (0==3): 0
ISIS HELLO
.... ..11 = Circuit type: Level 1 and 2 (0x03)
0000 00.. = Reserved: 0x00
SystemID {Sender of PDU}: 0000.0000.0004
Holding timer: 30
PDU length: 1497
.100 0000 = Priority: 64
0... .... = Reserved: 0
SystemID {Designated IS}: 0000.0000.0004.01
Protocols Supported (1)
NLPID(s): IP (0xcc)
Area address(es) (2)
Area address (1): 49
IP Interface address(es) (4)
IPv4 interface address: 192.168.3.4 (192.168.3.4)
Restart Signaling (3)
Restart Signaling Flags: 0x00
.... .0.. = Suppress Adjacency: False
.... ..0. = Restart Acknowledgment: False
.... ...0 = Restart Request: False
IS Neighbor(s) (6)
Padding (255)
Padding (255)
Padding (255)
Padding (255)
Padding (255)
Padding (157)
ISO 10589 ISIS InTRA Domain Routing Information Exchange Protocol
Intra Domain Routing Protocol Discriminator: ISIS (0x83)
PDU Header Length: 27
Version: 1
System ID Length: 0
...0 1111 = PDU Type: L1 HELLO (15)
000. .... = Reserved: 0x00
Version2 (==1): 1
Reserved (==0): 0
Max.AREAs: (0==3): 0
ISIS HELLO
.... ..01 = Circuit type: Level 1 only (0x01)
0000 00.. = Reserved: 0x00
SystemID {Sender of PDU}: 0000.0000.0002
Holding timer: 30
PDU length: 1497
.100 0000 = Priority: 64
0... .... = Reserved: 0
SystemID {Designated IS}: 0000.0000.0002.02
Protocols Supported (1)
NLPID(s): IP (0xcc)
Area address(es) (2)
Area address (1): 49
IP Interface address(es) (4)
IPv4 interface address: 192.168.3.2 (192.168.3.2)
Restart Signaling (3)
Restart Signaling Flags: 0x00
.... .0.. = Suppress Adjacency: False
.... ..0. = Restart Acknowledgment: False
.... ...0 = Restart Request: False
IS Neighbor(s) (6)
Padding (255)
Padding (255)
Padding (255)
Padding (255)
Padding (255)
Padding (157)
R4和R5之間的區域ID不同。R4為級別1-2,R5為級別2。因此,形成L2鄰接。
R4#show isis neighbors
Tag 1:
System Id Type Interface IP Address State Holdtime Circuit Id
R2 L1 Fa0/0 192.168.3.2 UP 19 R4.01
R5 L2 Fa1/1 192.168.5.5 UP 4 R5.01
R5和R7之間的區域ID相同。R5為第2級,R7為第2級。因此,形成L2鄰接。
R5#show isis neighbors
Tag 1:
System Id Type Interface IP Address State Holdtime Circuit Id
R4 L2 Fa0/0 192.168.5.4 UP 29 R5.01
R7 L2 Fa1/0 192.168.7.7 UP 4 R7.01
如前所述,L1路由器僅具有區域內的LSA,並使用最近的L1/L2路由器到達網路的其它部分。 L1區域的行為與OSPF完全末節區域相同。在路由表中可看到L1/L2路由器R4生成的預設路由。使用此預設路由,可以到達外部目的地。
R1#sh 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, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is 192.168.2.3 to network 0.0.0.0
i*L1 0.0.0.0/0 [115/20] via 192.168.2.3, 00:25:31, FastEthernet1/0
[115/20] via 192.168.1.2, 00:25:31, FastEthernet0/0
192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.1.0/24 is directly connected, FastEthernet0/0
L 192.168.1.1/32 is directly connected, FastEthernet0/0
192.168.2.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.2.0/24 is directly connected, FastEthernet1/0
L 192.168.2.1/32 is directly connected, FastEthernet1/0
i L1 192.168.3.0/24 [115/20] via 192.168.1.2, 00:25:31, FastEthernet0/0
i L1 192.168.4.0/24 [115/20] via 192.168.2.3, 03:17:05, FastEthernet1/0
i L1 192.168.5.0/24 [115/30] via 192.168.2.3, 00:25:31, FastEthernet1/0
-----------Output Omitted -----------
L1/L2路由器維護兩個鏈路狀態資料庫,一個用於L1區域,另一個用於L2區域。因此,需要兩個不同的SPF計算。
L1/L2路由器在L1區域中傳送預設路由,以便L1路由器可以到達網路的其它部分。此處可觀察L1和L2路由。
R4#sh 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, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
i L1 192.168.1.0/24 [115/20] via 192.168.3.2, 00:30:18, FastEthernet0/0
i L1 192.168.2.0/24 [115/20] via 192.168.4.3, 03:21:58, FastEthernet1/0
192.168.3.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.3.0/24 is directly connected, FastEthernet0/0
L 192.168.3.4/32 is directly connected, FastEthernet0/0
192.168.4.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.4.0/24 is directly connected, FastEthernet1/0
L 192.168.4.4/32 is directly connected, FastEthernet1/0
192.168.5.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.5.0/24 is directly connected, FastEthernet1/1
L 192.168.5.4/32 is directly connected, FastEthernet1/1
192.168.6.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.6.0/24 is directly connected, FastEthernet2/0
L 192.168.6.4/32 is directly connected, FastEthernet2/0
i L2 192.168.7.0/24 [115/20] via 192.168.5.5, 00:00:57, FastEthernet1/1
i L2 192.168.8.0/24 [115/20] via 192.168.6.6, 00:00:32, FastEthernet2/0
-----------Output Omitted -----------
L2路由器類似於OSPF主幹路由器。L2路由器中存在所有資訊。來自L1區域的環回在L2路由器的路由表中顯示為L2路由。
R7#sh 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, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
i L2 192.168.1.0/24 [115/40] via 192.168.8.6, 00:31:54, FastEthernet1/0
[115/40] via 192.168.7.5, 00:31:54, FastEthernet0/0
i L2 192.168.2.0/24 [115/40] via 192.168.8.6, 03:23:23, FastEthernet1/0
[115/40] via 192.168.7.5, 03:23:23, FastEthernet0/0
i L2 192.168.3.0/24 [115/30] via 192.168.8.6, 03:23:23, FastEthernet1/0
[115/30] via 192.168.7.5, 03:23:23, FastEthernet0/0
i L2 192.168.4.0/24 [115/30] via 192.168.8.6, 03:23:23, FastEthernet1/0
[115/30] via 192.168.7.5, 03:23:23, FastEthernet0/0
i L2 192.168.5.0/24 [115/20] via 192.168.7.5, 00:02:35, FastEthernet0/0
i L2 192.168.6.0/24 [115/20] via 192.168.8.6, 00:02:10, FastEthernet1/0
192.168.7.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.7.0/24 is directly connected, FastEthernet0/0
L 192.168.7.7/32 is directly connected, FastEthernet0/0
192.168.8.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.8.0/24 is directly connected, FastEthernet1/0
L 192.168.8.7/32 is directly connected, FastEthernet1/0
192.168.11.0/32 is subnetted, 1 subnets
i L2 192.168.11.11 [115/50] via 192.168.8.6, 03:23:23, FastEthernet1/0
[115/50] via 192.168.7.5, 03:23:23, FastEthernet0/0
192.168.22.0/32 is subnetted, 1 subnets
i L2 192.168.22.22 [115/40] via 192.168.8.6, 00:31:54, FastEthernet1/0
[115/40] via 192.168.7.5, 00:31:54, FastEthernet0/0
-----------Output Omitted -----------
目前尚無適用於此組態的具體疑難排解資訊。
修訂 | 發佈日期 | 意見 |
---|---|---|
3.0 |
25-Jun-2024 |
已更新替代文字、機器翻譯及格式設定。 |
2.0 |
09-Jan-2023 |
重新認證 |
1.0 |
14-Dec-2015 |
初始版本 |