本產品的文件集力求使用無偏見用語。針對本文件集的目的,無偏見係定義為未根據年齡、身心障礙、性別、種族身分、民族身分、性別傾向、社會經濟地位及交織性表示歧視的用語。由於本產品軟體使用者介面中硬式編碼的語言、根據 RFP 文件使用的語言,或引用第三方產品的語言,因此本文件中可能會出現例外狀況。深入瞭解思科如何使用包容性用語。
思科已使用電腦和人工技術翻譯本文件,讓全世界的使用者能夠以自己的語言理解支援內容。請注意,即使是最佳機器翻譯,也不如專業譯者翻譯的內容準確。Cisco Systems, Inc. 對這些翻譯的準確度概不負責,並建議一律查看原始英文文件(提供連結)。
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協定在網際網路服務提供商(ISP)環境中被廣泛用作內部網關協定(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、一些偵錯、擷取和輸出,以增進瞭解。
在本檔案中,IS-IS表示「整合IS-IS」。 部署了整合IS-IS,這意味著IS-IS正在路由網際網路協定(IP)。
IS-IS的真正力量在於它使用TLV(Type-Length-Value)使得IS-IS協定具有高可擴充性。
隨著新功能的引入,它們可以通過TLV新增到協定中。
在OSPF協定中,可以將路由器的任何介面分配給特定區域。然而,IS-IS中的區域概念是不同的。一般來說,這裡的每台路由器都屬於一個區域。
這個想法源於最初建立的IS-IS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,地址屬於特定的介面。
IS-IS協定有兩個級別或層次:級別1和級別2。
第1級對應於OSPF區域內路由,而第2級對應於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,每台Cisco路由器都作為1-2級(L1/L2)路由器提供。
1級路由器可能與1級和1-2級(L1/L2)路由器相鄰。
第2級路由器可能與第2級或第1-2級(L1/L2)路由器相鄰。
僅L1和僅L2路由器之間沒有鄰接關係。
IS-IS第1級路由器具有所有區域內拓撲各自區域的鏈路狀態資訊。為了將資料包路由到其他區域,它使用距離最近的2級(L1/L2)路由器。
第1級區域的行為與OSPF完全末節區域的行為非常相似。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。
將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級路由器的行為非常接近OSPF區域邊界路由器(ABR)。L1/L2路由器同時傳送L1和L2 hello。
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 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 |
如果區域ID匹配,則使用L1鄰接,否則不使用Adjacency |
如果區域ID匹配,則使用L1鄰接,否則不使用Adjacency |
無鄰接關係 |
L1/L2 |
如果區域ID匹配,則使用L1鄰接,否則不使用Adjacency |
如果區域ID匹配,則為L1和L2鄰接,否則僅為L2鄰接 |
L2鄰接,區域ID不重要 |
L2 |
無鄰接關係 |
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高於它所能支援的MTU(在介面上),它將丟棄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。 |
Circuit-Type |
此屬性在介面上配置並定義什麼型別的hello,即L1或L2在特定介面上傳送。 L1/L2路由器可以選擇性地在一個介面上只傳送L1 hello,而在另一個介面上只傳送L2 hello。 如果L1/L2路由器嘗試與僅使用L1的路由器建立對等關係,並且L1/L2介面配置了「isis circuit-type level-2」,則它只向介面傳送L2 hello消息,並且與L1路由器的鄰接關係不會出現。 路由器必須傳送相容型別的hello。 |
驗證 |
IS-IS可以單獨對hello和鏈路狀態協定資料單元(LSP)進行身份驗證。如果hello身份驗證正確且LSP身份驗證失敗,則鄰接會出現,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,則它會預設為忽略TLV。 但是,當一台路由器達到INIT狀態而另一台路由器丟棄資料包且不形成鄰接時,由於功能不匹配,會發生一些事件。 作為一般建議,功能TLV必須匹配才能成功建立鄰接關係。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 network point-to-point」,而另一端是預設網路型別,則系統會丟棄hello,且不建立鄰接關係。 兩端的網路型別必須匹配。 |
海洛斯 |
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。
Down:這是初始狀態。這意味著沒有收到來自鄰居的hello。
正在初始化:此狀態表示本地路由器已成功收到來自鄰居路由器的hello資料包,但是,不確定該鄰居路由器是否也成功收到本地hello資料包。
Up:現在,確認鄰居路由器收到本地路由器的hello資料包。
子網屬於192.168.X.0型別,其中X顯示在圖中的介面之間。
環回的型別為192.168.YY.YY,其中Y為1,而Router為R1。因此,R1的環回ip是192.168.11.11。
L1、L1/L2和L2分別是第1級、第1-2級和第2級路由器。
IS-IS協定需要在介面級別和全域性級別進行配置。
!
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。兩者都是1級路由器。 它們之間存在L1鄰接關係。
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網段上只提供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,用於在建立鄰接關係之前檢測介面上的MTU。
建立鄰接關係後,不會由於MTU問題而發生資料包丟棄,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,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始終傳送正常呼叫時間的三分之一(即10秒)的hello消息。
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。這也可從以下輸出中驗證。
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。
因為R4是L1/L2路由器,所以它同時傳送L1和L2 hello(如前所述)。
R2僅是第1層路由器,且區域ID相同,因此形成L1鄰接關係。
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 Routeing 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 Routeing 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 Routeing 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1-2級,R5為2級。因此形成了L2鄰接關係。
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2級,R7為2級。因此形成了L2鄰接關係。
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。路由表中顯示了由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。此處觀察到了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路由器與OSPF主幹路由器類似。所有資訊都存在於L2路由器中。來自L1區域的環回作為L2路由器的路由表中的L2路由存在。
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 |
---|---|---|
2.0 |
09-Jan-2023 |
重新認證 |
1.0 |
14-Dec-2015 |
初始版本 |