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本文档介绍中间系统到中间系统 (IS-IS) 协议邻接关系和区域类型。
本文档不限于特定的软件和硬件版本。
本文档中的信息都是基于特定实验室环境中的设备编写的。本文档中使用的所有设备最初均采用原始(默认)配置。如果您的网络处于活动状态,请确保您了解所有命令的潜在影响。
IS-IS协议被广泛用作互联网服务提供商(ISP)环境中的内部网关协议(IGP)。本文档的范围是提供有关IS-IS区域类型、配置和故障排除的信息。它显示了一个示例网络场景及其配置,以及一些调试、捕获和输出,以便更好地理解。
在本文中,IS-IS表示集成IS-IS。集成IS-IS已部署,这意味着IS-IS是路由互联网协议(IP)。 IS-IS的真正力量在于它使用类型长度值(TLV)使得IS-IS协议具有高度可扩展性。 随着新功能的引入,它们可以与TLV一起添加到协议中。
在OSPF协议中,路由器的任何接口都可以分配给特定区域。但是,IS-IS中的区域概念不同。一般而言,这里的每台路由器属于一个区域。
这种想法源于最初创建IS-IS以路由无连接网络协议(CLNP),其中地址属于设备(路由器),而在Internet协议(IP)中,地址属于特定接口。
IS-IS协议有两个级别或层次结构,即级别1和级别2。
级别1对应于OSPF区域内路由,而级别2对应于OSPF主干区域0路由。
2级区域将所有区域与主干区域连接起来。
默认情况下,每台Cisco路由器都作为1-2级(L1/L2)路由器提供。
1级路由器可以与1级和1-2级(L1/L2)路由器邻接。
2级路由器可以与2级或1-2级(L1/L2)路由器邻接。
仅L1路由器和仅L2路由器之间没有邻接关系。
对于所有区域内拓扑,IS-IS第1级路由器具有其自己区域的链路状态信息。为了将数据包路由到其他区域,它使用最近的第2级路由器(L1/L2)。 第1级区域的行为与OSPF完全末节区域大致相同。L1是发送L1 Hello的唯一路由器。
IS-IS L1/L2路由器维护两个链路状态数据库信息。
一个用于级别1,另一个用于级别2。
将运行两个不同的最短路径优先(SPF)计算;一个在第1级链路状态数据库中,另一个在第2级链路状态数据库中。
IS-IS级别1-2路由器的行为非常接近OSPF区域边界路由器(ABR)。L1/L2路由器发送L1和L2 Hello数据包。
默认情况下,L1/L2路由器允许前缀从L1区域到L2区域单向通过,但不允许反向通过。
但是,如果需要将前缀从L2区域移动到L1区域,则需要在IS-IS配置下执行redistribute命令。
IS-IS第2级路由器具有区域内和区域间路由的链路状态信息。
L2路由器仅发送L2 Hello数据包。IS-IS第2级区域可与OSPF主干区域0进行比较。
IS-IS邻接表
路由器类型 |
L1 |
L1/L2 |
L2 |
L1 |
L1邻接(如果区域ID匹配),否则无邻接 |
L1邻接(如果区域ID匹配),否则无邻接 |
无邻接 |
L1/L2 |
L1邻接(如果区域ID匹配),否则无邻接 |
L1和L2邻接(如果区域ID匹配),否则仅L2邻接 |
L2邻接,区域ID不重要 |
L2 |
无邻接 |
L2邻接,区域ID不重要 |
L2邻接,区域ID不重要 |
MTU |
如果一个IS-IS路由器收到的ISIS hello数据包的MTU高于其可支持的MTU(在接口上),则它会丢弃hello,因此不会出现邻接关系。在最佳实践中,两端的MTU必须相同。 |
电路类型 |
此属性在接口上配置并定义哪种hello类型,即L1或L2在特定接口上发送。 L1/L2路由器可以选择性地在一个接口上只发送L1 hello数据包,而在另一个接口上只发送L2 hello数据包。 如果L1/L2路由器尝试与L1专用路由器对等,并且L1/L2接口配置了isis circuit-type level-2,则它仅向接口发送L2 hello数据包,且与L1路由器的邻接关系未建立。 路由器必须发送兼容类型的hello数据包。 |
身份验证 |
IS-IS可以分别对Hello和链路状态协议数据单元(LSP)进行身份验证。如果Hello数据包的身份验证正确,并且LSP身份验证失败,则邻接关系会建立,但更新不会交换。 如果为IS-IS hello或PDU(协议数据单元)配置了身份验证,则两端必须匹配。 |
功能TLV |
如果某个IS-IS路由器不支持来自另一个IS-IS路由器的功能TLV,则会静默忽略TLV。 但是,当一台路由器到达INIT状态时,由于功能不匹配,会发生一些事件,而另一台路由器会丢弃数据包且无法形成邻接关系。 作为一般建议,功能TLV必须匹配才能成功形成邻接关系。有关功能TLV的详细信息的讨论不属于本文档的讨论范围。 |
网络类型 |
IS-IS中有两种网络类型:广播和点对点。广播是默认网络类型。 如果一端配置了isis network point-to-point,而另一端是默认网络类型,则hello数据包将被丢弃,并且不会建立邻接关系。 两端的网络类型必须匹配。 |
Hello |
Hello计时器无需匹配即可建立邻接关系。 |
IS-IS中只有三种邻接状态。
子网属于192.168.X.0类型,其中X显示在图中的接口之间。
环回接口的类型为192.168.YY.YY,其中Y为1(当路由器为R1时)。因此,R1的环回IP是192.168.11.11。
L1、L1/L2和L2分别是1级、1-2级和2级路由器。
IS-IS协议需要在接口级别和全局级别进行配置。
!
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中的区域ID相同。两者都是1级路由器。 它们之间存在L1邻接。
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
由于R1和R2都是L1路由器并且属于同一区域,因此只有第1层类型IS-IS hello源于R1和R2之间的LAN网段。
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®实施了一种机制,用于在建立邻接之前检测接口上的MTU。
建立邻接关系后,不会因MTU问题发生丢包,从而防止数据库损坏。
填充IS-IS Hello会增加其大小,直到接口的MTU为止,并且观察另一端是否可以接受具有此MTU的Hello数据包。
如果在另一端退出较低的MTU,则该端会丢弃Hello数据包,因此不会建立邻接关系。
在IS-IS中,广播LAN网段中的DR始终发送hello数据包,发送时间为正常hello时间的三分之一,即10秒。 从DR的角度来看,Hello时间为3.33秒,保持时间为10秒。在之前的捕获示例中,R2是DR。这也可以从以下输出进行验证。
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之间的区域ID相同。R2为级别1,R4为级别1-2。
如前所述,由于R4是L1/L2路由器,因此它同时发送L1和L2 Hello。
R2是L1唯一路由器,区域ID相同,因此形成L1邻接关系。
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之间的区域ID不同。R4为级别1-2,R5为级别2。因此形成L2邻接。
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之间的区域ID相同。R5为级别2,R7为级别2。因此形成L2邻接。
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路由器只有区域内的LSA,并使用最近的L1/L2路由器到达网络的其他部分。 L1区域充当OSPF完全末节区域。路由表中显示L1/L2路由器R4生成的默认路由。使用此默认路由可以到达外部目的地。
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路由器维护两个链路状态数据库,一个用于L1区域,另一个用于L2区域。因此,需要两个不同的SPF计算。
L1/L2路由器在L1区域中发送默认路由,以便L1路由器可以到达网络的其它部分。此处观察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路由器类似于OSPF主干路由器。所有信息都存在于L2路由器中。来自L1区域的环回作为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 -----------
目前没有针对此配置的故障排除信息。
版本 | 发布日期 | 备注 |
---|---|---|
3.0 |
25-Jun-2024 |
更新的Alt文本、机器翻译和格式。 |
2.0 |
09-Jan-2023 |
重新认证 |
1.0 |
14-Dec-2015 |
初始版本 |