13.16 IRDP

Hi,

Although I consulted the RFc for IRDP, I still don't get it why gateway is changing for SW1, as presented in the SG for this task :

 

Rack18SW1#sh ip route
Gateway         Using  Interval  Priority   Interface
155.18.58.8     IRDP       15       500     Vlan58
155.18.58.5     IRDP       14      1000     Vlan58

Default gateway is 155.18.58.8

Host               Gateway           Last Use    Total Uses  Interface
ICMP redirect cache is empty

In the RFC 1256 it clearly states that higher value is more preferrable. Ok, now, why is the gateway being balanced the two ?

I had it like this earlier :

Rack18SW1#sh ip route
Gateway         Using  Interval  Priority   Interface
155.18.58.8     IRDP       15       500     Vlan58
155.18.58.5     IRDP       16      1000     Vlan58

Default gateway is 155.18.58.5

Host               Gateway           Last Use    Total Uses  Interface
ICMP redirect cache is empty

R5 and Sw2 config :

Rack18R5#sh run int fa 0/0 | i irdp
 ip irdp
 ip irdp maxadvertinterval 20
 ip irdp minadvertinterval 10
 ip irdp holdtime 60
 ip irdp preference 1000

Rack18SW2#sh run int vl 58 | i irdp
 ip irdp
 ip irdp maxadvertinterval 20
 ip irdp minadvertinterval 10
 ip irdp holdtime 60
 ip irdp preference 500

 

I used this option < ip irdp preference 500 >, as well as the presented solution in SG : ip irdp address a.b.c.d preference, no difference.

Any ideas ? Did you guys have these issues ?

 

Thank,

Ciprian.

 

Comments

  • Hi,

    What I have noticed is that the device SW1 hears from first gets added as the default gateway. In my case also, SW2 has become the gateway and whenever I ping any device behind SW2 say SW4 then the ping response is successfull and no new entry is added in the route table.

    But if I ping R4 which is behind R5, it will ping successfully and a new route entry is added to the route table.

    Rack7SW1#show ip route  

    Gateway         Using  Interval  Priority   Interface

    155.7.58.8      IRDP       24       500     Vlan58

    155.7.58.5      IRDP       30      1000     Vlan58

     

    Default gateway is 155.7.58.8

     

    Host               Gateway           Last Use    Total Uses  Interface

    150.7.4.4          155.7.58.5            0:00             8  Vlan58

    Rack7SW1#

     

    Only if there was some preempt feature that would automatically make R5 the default gateway since R5 is having a better (higher) priority value.

     

Sign In or Register to comment.