experimental topology
Note: Unless otherwise specified, R1 or SW1 in the description corresponds to the device whose device name ends with 1 in the topology, R2 or SW2 corresponds to the device whose device name ends with 2 in the topology, and so on; in addition, in the same network segment , the host bit of the IP address is its device number, for example, if the g0/0 interface of R3 is in the 192.168.1.0/24 network segment, its IP address is 192.168.1.3/24, and so on
Experimental requirements
Configure IP addresses
as shown in the figure. Configure IS-IS by region as shown in the figure to complete network-wide intercommunication. The NET address is shown in the figure. It
is required that R1 and R2/R3 only establish Level-1 adjacency
. R2 and R3 only establish Level-1 adjacency. Relationship
Modify the cost of each link as shown in the figure.
Configure route penetration on R2 and R3, so that R1 can learn the detailed routes of 100.1.1.0 and 24 network segments, and select the optimal path.
Configure interface verification on the backbone network
Experimental solution:
1. Configure the IP address part is omitted.
2. Configure IS-IS by region according to the figure to complete the intercommunication of the whole network. The NET address is shown in the figure
Analysis: The IS-IS configuration method is to first create the IS-IS process, configure the NET address, and then enable IS-IS on the interface that needs to be declared
Step 1: Create an IS-IS process on R1 and configure the NET address
[R1]isis 1
[R1-isis-1]network-entity 49.0000.0000.0000.0001.00
Step 2: Enable IS-IS on the interface connecting R2 and R3 on R1
[R1]interface g0/0
[R1-GigabitEthernet0/0]isis enable 1
[R1]interface g0/1
[R1-GigabitEthernet0/1]isis enable 1
Step 3: The configuration steps on R2, R3, and R4 are the same as those on R1, and enable IS-IS on all interfaces. step by step
3. Require R1 and R2/R3 to establish only Level-1 adjacency
Analysis: The default level of IS-IS routers is Level-1-2, R1, R2, and R3 are in the same area, so R1 and R2/R3 will establish Level-1 and Level-2 adjacencies at the same time, resulting in the establishment of duplicate Adjacency increases the performance pressure of the router and wastes network bandwidth.
R1 and R2/R3 belong to the same area, so it is only necessary to establish a Level-1 adjacency relationship and change the router level of R1 to Level-1.
Step 1: Change the router level of R1 to Level-1
[R1]isis 1
[R1-isis-1]is-level level-1
Effect test: Check the adjacency of R1, and find that only the adjacency of Level-1 remains between R1 and R2/R3
[R1]display isis peer
Peer information for IS-IS(1)
-----------------------------
System ID: 0000.0000.0002
Interface: GE0/0 Circuit Id: 0000.0000.0002.01
State: Up HoldTime: 7s Type: L1(L1L2) PRI: 64
System ID: 0000.0000.0003
Interface: GE0/1 Circuit Id: 0000.0000.0003.01
State: Up HoldTime: 9s Type: L1(L1L2) PRI: 64
4. R2 and R3 are required to establish only Level-1 adjacency
Analysis: The default level of IS-IS routers is Level-1-2, and R2 and R3 are in the same area, so R2 and R3 will establish Level-1 and Level-2 adjacencies at the same time, resulting in the establishment of re-adjacency, increasing the router's Performance pressure, wasting network bandwidth
R2 and R3 belong to the same area, so only need to establish a Level-1 adjacency relationship; but because R2 and R3 are connected to other area routers at the same time, so the router level cannot be changed to Level-1, only It can be solved by changing the interface adjacency level to Level-1
Step 1: Change the adjacency level of the directly connected interface between R2 and R3 to Level-1
[R2]interface g0/2
[R2-GigabitEthernet0/2]isis circuit-level level-1
[R3]interface g0/2
[R3-GigabitEthernet0/2]isis circuit-level level-1
Effect test: Check the adjacency relationship between R2 and R3, and find that only Level-1 adjacency remains between R2 and R3
[R2]display isis peer
Peer information for IS-IS(1)
-----------------------------
System ID: 0000.0000.0001
Interface: GE0/0 Circuit Id: 0000.0000.0002.01
State: Up HoldTime: 28s Type: L1 PRI: 64
System ID: 0000.0000.0004
Interface: GE0/1 Circuit Id: 0000.0000.0004.01
State: Up HoldTime: 8s Type: L2(L1L2) PRI: 64
System ID: 0000.0000.0003
Interface: GE0/2 Circuit Id: 0000.0000.0003.03
State: Up HoldTime: 8s Type: L1 PRI: 64
5. Modify the cost of each link according to the diagram
Step 1: Modify Cost
[R1]interface g0/0
[R1-GigabitEthernet0/0]isis cost 5
[R1]interface g0/1
[R1-GigabitEthernet0/1]isis cost 10
6. Configure route penetration on R2 and R3, so that R1 can learn the detailed routes of 100.1.1.0 and 24 network segments, and choose the optimal path
Analysis: According to the principles of the IS-IS protocol, the Level-2 detailed route will not be passed to the Level-1 router by default, but a default route will be automatically generated by the Level-1-2 router in the area and advertised to the Level-1 router. The default route will not calculate the cost outside the area, so in this experiment environment, when reaching the network segment 100.1.1.0/24 on R1, it will choose to go through R2. This path is not the optimal path to the network segment.
To realize R1 selecting the optimal path, it is necessary to configure route percolation on the Level-1-2 router, and allow the detailed routes of Level-2 to be published to the Level-1 router. Let R1 learn the optimal route to the 100.1.1.0/24 network segment
Step 1: Configure route leaking on R2 and R3
[R2]isis 1
[R2-isis-1]address-family ipv4
[R2-isis-1-ipv4]import-route isis level-2 into level-1
[R3]isis 1
[R3-isis-1]address-family ipv4
[R3-isis-1-ipv4]import-route isis level-2 into level-1
Effect test: Check the routing table of R1, and find that the detailed route of the 100.1.1.0/24 network segment has been learned, and it points to R3
[R1]display ip routing-table
Destinations : 21 Routes : 21
Destination/Mask Proto Pre Cost NextHop Interface
0.0.0.0/0 IS_L1 15 5 192.168.1.2 GE0/0
0.0.0.0/32 Direct 0 0 127.0.0.1 InLoop0
100.1.1.0/24 IS_L1 15 25 192.168.2.3 GE0/1
……
7. Configure interface authentication on the backbone network
Analysis: In IS-IS, the network composed of continuous Level-2 and Level-1-2 routers is the backbone network. In this topology, the network composed of R2, R4, and R3 is the backbone network, which needs to be interconnected Configure interface authentication on the interface
Step 1: Configure IS-IS interface authentication on the interface connecting R2, R4, and R3
[R2-GigabitEthernet0/1]isis authentication-mode simple plain 123456
[R3-GigabitEthernet0/1]isis authentication-mode simple plain 123456
[R4-GigabitEthernet0/0]isis authentication-mode simple plain 123456
[R4-GigabitEthernet0/1]isis authentication-mode simple plain 123456
Effect test: After restarting the interface or resetting the IS-IS process, it is found that the IS-IS adjacency relationship can still be successfully established, indicating that the verification configuration is correct