R1

hostname R1

!

interface Loopback0

 ip address 1.1.1.1 255.255.255.255

 ip router isis

!        

interface FastEthernet0/0

 description to R2

 ip address 10.0.12.1 255.255.255.0

 ip router isis

!

interface FastEthernet0/1

 description to R3

 ip address 10.0.13.1 255.255.255.0

 ip router isis

!

router isis

 net 10.0000.0000.0001.00

=========================

R2

interface Loopback0

 ip address 2.2.2.2 255.255.255.255

 ip router isis

!        

interface FastEthernet0/0

 description to R5

 ip address 10.0.25.2 255.255.255.0

 ip router isis

!

interface FastEthernet0/1

 description to R1

 ip address 10.0.12.2 255.255.255.0

 ip router isis

!

router isis

 net 10.0000.0000.0002.00

=========================

R3

interface Loopback0

 ip address 3.3.3.3 255.255.255.255

 ip router isis

!        

interface FastEthernet0/0

 description to R1

 ip address 10.0.13.3 255.255.255.0

 ip router isis

!

interface FastEthernet0/1

 description to R4

 ip address 10.0.34.3 255.255.255.0

 ip router isis

!

router isis

 net 10.0000.0000.0003.00

=========================

R4

interface Loopback0

 ip address 4.4.4.4 255.255.255.255

 ip router isis

!        

interface FastEthernet0/0

 description to R3

 ip address 10.0.34.4 255.255.255.0

 ip router isis

!

interface FastEthernet0/1

 description to R5

 ip address 10.0.45.4 255.255.255.0

 ip router isis

!

router isis

 net 10.0000.0000.0004.00

=========================

R5

interface Loopback0

 ip address 5.5.5.5 255.255.255.255

 ip router isis

!        

interface FastEthernet0/0

 description to R4

 ip address 10.0.45.5 255.255.255.0

 ip router isis

!

interface FastEthernet0/1

 description to R2

 ip address 10.0.25.5 255.255.255.0

 ip router isis

!

interface FastEthernet1/0

 description to R6

 ip address 10.0.56.5 255.255.255.0

 ip router isis

!

router isis

 net 10.0000.0000.0005.00

=========================

R6

interface Loopback0

 ip address 6.6.6.6 255.255.255.255

 ip router isis

!        

interface FastEthernet0/0

 description to R5

 ip address 10.0.56.6 255.255.255.0

 ip router isis

!

router isis

 net 10.0000.0000.0006.00

=========================