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tech:network:irdp:irdp

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IRDP

ICMP Router Discovery Protocol.

Home Physical Lab Topologies

Configuration

R1

en
conf t
int f0/0
ip addr 172.16.2.1 255.255.255.0
no shut
int f0/1
ip addr 172.16.1.1 255.255.255.0
no shut
end

R2

en
conf t
int f0/0
ip addr 172.16.2.2 255.255.255.0
no shut
int f0/1
ip addr 172.16.1.2 255.255.255.0
no shut
end

R3

Using R3 as IRDP Host.

en
conf t
int f0/0
ip addr 172.16.1.100 255.255.255.0
no shut
end

Pi0

sudo ip route add 172.16.0.0/16 via 172.16.2.2

Review Current State

R1#sh ip ro
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

      172.16.0.0/16 is variably subnetted, 4 subnets, 2 masks
C        172.16.1.0/24 is directly connected, FastEthernet0/1
L        172.16.1.1/32 is directly connected, FastEthernet0/1
C        172.16.2.0/24 is directly connected, FastEthernet0/0
L        172.16.2.1/32 is directly connected, FastEthernet0/0
R2#sh ip ro
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

      172.16.0.0/16 is variably subnetted, 4 subnets, 2 masks
C        172.16.1.0/24 is directly connected, FastEthernet0/1
L        172.16.1.2/32 is directly connected, FastEthernet0/1
C        172.16.2.0/24 is directly connected, FastEthernet0/0
L        172.16.2.2/32 is directly connected, FastEthernet0/0
R3#sh ip ro
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

      172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks
C        172.16.1.0/24 is directly connected, FastEthernet0/0
L        172.16.1.100/32 is directly connected, FastEthernet0/0

IRDP Configuration

R1

R1#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R1(config)#int f0/1
R1(config-if)#ip irdp
R1(config-if)#ip irdp maxadvertinterval 6
R1(config-if)#ip irdp minadvertinterval 3
R1(config-if)#ip irdp holdtime 18
R1(config-if)#ip irdp preference 100
R1(config-if)#end
R1#
*Mar  4 10:05:09.651: %SYS-5-CONFIG_I: Configured from console by console

R2

R2#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R2(config)#int f0/1
R2(config-if)#ip irdp
R2(config-if)#ip irdp maxadvertinterval 6
R2(config-if)#ip irdp minadvertinterval 3
R2(config-if)#ip irdp holdtime 18
R2(config-if)#ip irdp preference 18
R2(config-if)#end
R2#
*Mar  4 11:15:21.235: %SYS-5-CONFIG_I: Configured from console by console

This timing, last resort gateway not set.

R3#sh ip ro
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

      172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks
C        172.16.1.0/24 is directly connected, FastEthernet0/0
L        172.16.1.100/32 is directly connected, FastEthernet0/0

R3

Now configure IRDP client. This scene, using R3.

R3#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R3(config)#no ip routing
R3(config)#ip gdp ?
  eigrp  Discover routers transmitting EIGRP router updates
  irdp   Discover routers transmitting IRDP router updates
  rip    Discover routers transmitting RIP router updates

R3(config)#ip gdp irdp
R3(config)#^Z
R3#
*Mar  4 11:18:28.999: %SYS-5-CONFIG_I: Configured from console by console

Verification

R1#sh ip irdp
FastEthernet0/0 has router discovery disabled

FastEthernet0/1 has router discovery enabled

Advertisements will occur between every 3 and 6 seconds.
Advertisements are sent with broadcasts.
Advertisements are valid for 18 seconds.
Default preference will be 100.
Serial0/0/0 has router discovery disabled
R1#sh ip ro
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

      172.16.0.0/16 is variably subnetted, 4 subnets, 2 masks
C        172.16.1.0/24 is directly connected, FastEthernet0/1
L        172.16.1.1/32 is directly connected, FastEthernet0/1
C        172.16.2.0/24 is directly connected, FastEthernet0/0
L        172.16.2.1/32 is directly connected, FastEthernet0/0
R2#sh ip irdp
FastEthernet0/0 has router discovery disabled

FastEthernet0/1 has router discovery enabled

Advertisements will occur between every 3 and 6 seconds.
Advertisements are sent with broadcasts.
Advertisements are valid for 18 seconds.
Default preference will be 18.
Serial0/0/0 has router discovery disabled

R2#sh ip ro
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

      172.16.0.0/16 is variably subnetted, 4 subnets, 2 masks
C        172.16.1.0/24 is directly connected, FastEthernet0/1
L        172.16.1.2/32 is directly connected, FastEthernet0/1
C        172.16.2.0/24 is directly connected, FastEthernet0/0
L        172.16.2.2/32 is directly connected, FastEthernet0/0
R3#ping 172.16.2.250
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.2.250, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/202/1000 ms
R3#tracerou 172.16.2.250
R3#tracerou 172.16.2.250 ?
  numeric  display numeric address
  port     specify port number
  probe    specify number of probes per hop
  source   specify source address or name
  timeout  specify time out
  ttl      specify minimum and maximum ttl
  <cr>

R3#tracerou 172.16.2.250 numer
R3#tracerou 172.16.2.250 numeric
Type escape sequence to abort.
Tracing the route to 172.16.2.250
VRF info: (vrf in name/id, vrf out name/id)
  1 172.16.1.1 0 msec 4 msec 0 msec
  2 172.16.2.250 0 msec 4 msec 0 msec

then, shutdown R1 f0/1

R1#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R1(config)#int f0/1
R1(config-if)#shut
R1(config-if)#^Z
R1#
*Mar  4 10:13:01.207: %SYS-5-CONFIG_I: Configured from console by console
R1#
*Mar  4 10:13:02.411: %LINK-5-CHANGED: Interface FastEthernet0/1, changed state to administratively down
*Mar  4 10:13:03.411: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down
R3#sh ip ro
Gateway         Using  Interval  Priority   Interface
172.16.1.2      IRDP        4        18     FastEthernet0/0

Default gateway is 172.16.1.2

Host               Gateway           Last Use    Total Uses  Interface
ICMP redirect cache is empty
R3#ping 172.16.2.250
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.2.250, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/200/1000 ms
R3#tracerou 172.16.2.250 numeric
Type escape sequence to abort.
Tracing the route to 172.16.2.250
VRF info: (vrf in name/id, vrf out name/id)
  1 172.16.1.2 4 msec 0 msec 4 msec
  2 172.16.2.250 0 msec 0 msec 4 msec

then no shut R1 f0/1

R1#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R1(config)#int f0/1
R1(config-if)#no shut
R1(config-if)#
*Mar  4 10:14:57.655: %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to up
*Mar  4 10:14:58.655: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up

failback not occured.

R3#sh ip ro
Gateway         Using  Interval  Priority   Interface
172.16.1.2      IRDP        4        18     FastEthernet0/0
172.16.1.1      IRDP        7       100     FastEthernet0/0

Default gateway is 172.16.1.2

Host               Gateway           Last Use    Total Uses  Interface
ICMP redirect cache is empty
R3#traceroute 172.16.2.250 numeric
Type escape sequence to abort.
Tracing the route to 172.16.2.250
VRF info: (vrf in name/id, vrf out name/id)
  1 172.16.1.2 0 msec 0 msec 4 msec
  2 172.16.2.250 0 msec 0 msec 4 msec
R3#ping 172.16.2.250
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.2.250, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms

then shut down all interfaces.

R1#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R1(config)#int f0/1
R1(config-if)#shut
R1(config-if)#
*Mar  4 10:17:03.719: %LINK-5-CHANGED: Interface FastEthernet0/1, changed state to administratively down
*Mar  4 10:17:04.719: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down
R2#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R2(config)#int f0/1
R2(config-if)#shut
R2(config-if)#
*Mar  4 11:27:15.311: %LINK-5-CHANGED: Interface FastEthernet0/1, changed state to administratively down
*Mar  4 11:27:16.311: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down
R3#sh ip ro
Gateway         Using  Interval  Priority   Interface

Default gateway is not set

Host               Gateway           Last Use    Total Uses  Interface
ICMP redirect cache is empty
R3#ping 172.16.2.250
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.2.250, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
R3#traceroute 172.16.2.250 numeric
Type escape sequence to abort.
Tracing the route to 172.16.2.250
VRF info: (vrf in name/id, vrf out name/id)
  1  *  *  *
  2  *  *  *
  3  *  *  *
  4  *  *

lost ip connectivity.

no shut!!

R1#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R1(config)#
*Mar  4 10:18:47.711: %SYS-5-CONFIG_I: Configured from console by console
R1(config)#int f0/1
R1(config-if)#no shut
R1(config-if)#
*Mar  4 10:18:59.167: %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to up
*Mar  4 10:19:00.167: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up
R2#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R2(config)#int f0/1
R2(config-if)#no shut
R2(config-if)#
*Mar  4 11:29:10.751: %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to up
*Mar  4 11:29:11.751: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up
R1(config-if)#do sh ip irdp
FastEthernet0/0 has router discovery disabled

FastEthernet0/1 has router discovery enabled

Advertisements will occur between every 3 and 6 seconds.
Advertisements are sent with broadcasts.
Advertisements are valid for 18 seconds.
Default preference will be 100.
Serial0/0/0 has router discovery disabled
R2(config-if)#do sh ip irdp
FastEthernet0/0 has router discovery disabled

FastEthernet0/1 has router discovery enabled

Advertisements will occur between every 3 and 6 seconds.
Advertisements are sent with broadcasts.
Advertisements are valid for 18 seconds.
Default preference will be 18.
Serial0/0/0 has router discovery disabled
R3#sh ip ro
Gateway         Using  Interval  Priority   Interface
172.16.1.1      IRDP        6       100     FastEthernet0/0
172.16.1.2      IRDP        6        18     FastEthernet0/0

Default gateway is 172.16.1.1

Host               Gateway           Last Use    Total Uses  Interface
ICMP redirect cache is empty
R3#ping 172.16.2.250
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.2.250, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
R3#traceroute 172.16.2.250 numeric
Type escape sequence to abort.
Tracing the route to 172.16.2.250
VRF info: (vrf in name/id, vrf out name/id)
  1  *
    172.16.1.1 0 msec 0 msec
  2 172.16.2.250 4 msec 0 msec 0 msec

OK.

References

tech/network/irdp/irdp.1520163879.txt.gz · Last modified: 2018/03/04 20:44 by wnoguchi