From: Adel Abushaev (adel@netmasterclass.net)
Date: Fri Jan 09 2004 - 01:15:28 GMT-3
Folks,
I think Nathasha is right in her question. There is a bug in it's
implementation. My observations show that it does not
compare them neither as signed, nor as unsigned.
It just takes an absolute value of the preference and compares it.
Therefore -10 and 10 are equal. When preferences are
equal, the lowest IP address wins. Otherwise, the highest absolute number
wins.
Take a look at configurations and "sh ip route" below. You may notice a
system in how theses results are derived from
ip irdp parameters.
The remedy is to use only positive numbers when working with ip irdp
preference.
Thanks,
Adel Abouchaev
CCIE# 12037, MCSE
http://www.netmasterclass.net
R1: IOS (tm) 3600 Software (C3640-JK8O3S-M), Version 12.2(15)T7, RELEASE
SOFTWARE (fc2)
!
interface FastEthernet0/0
ip address 10.0.0.1 255.255.255.0 (I have changed this address to
10.0.0.9 in last 2 cases)
ip irdp
ip irdp maxadvertinterval 10
ip irdp minadvertinterval 3
ip irdp holdtime 30
ip irdp preference -10
duplex auto
speed auto
!
R2: IOS (tm) 3600 Software (C3640-JK8O3S-M), Version 12.2(15)T7, RELEASE
SOFTWARE (fc2)
!
no ip routing
!
!
interface FastEthernet0/0
ip address 10.0.0.2 255.255.255.0
no ip route-cache
duplex auto
speed auto
!
ip gdp irdp
!
R3: IOS (tm) C2600 Software (C2600-JK8O3S-M), Version 12.2(4)T7, RELEASE
SOFTWARE (fc1)
!
!
interface FastEthernet0/0
ip address 10.0.0.3 255.255.255.0
ip irdp
ip irdp maxadvertinterval 10
ip irdp minadvertinterval 3
ip irdp holdtime 30
ip irdp preference 10
duplex auto
speed auto
!
R2#sh ip route
Gateway Using Interval Priority Interface
10.0.0.1 IRDP 6 - 10 FastEthernet0/0
10.0.0.3 IRDP 6 10 FastEthernet0/0
Default gateway is 10.0.0.1
R2#sh ip route
Gateway Using Interval Priority Interface
10.0.0.1 IRDP 7 - 10 FastEthernet0/0
10.0.0.3 IRDP 5 - 20 FastEthernet0/0
Default gateway is 10.0.0.3
R2#sh ip route
Gateway Using Interval Priority Interface
10.0.0.1 IRDP 5 10 FastEthernet0/0
10.0.0.3 IRDP 6 20 FastEthernet0/0
Default gateway is 10.0.0.3
R2#sh ip route
Gateway Using Interval Priority Interface
10.0.0.1 IRDP 6 - 11 FastEthernet0/0
10.0.0.3 IRDP 5 10 FastEthernet0/0
Default gateway is 10.0.0.1
R2#sh ip route
Gateway Using Interval Priority Interface
10.0.0.3 IRDP 7 10 FastEthernet0/0
10.0.0.9 IRDP 12 10 FastEthernet0/0
Default gateway is 10.0.0.3
R2#sh ip route
Gateway Using Interval Priority Interface
10.0.0.3 IRDP 6 10 FastEthernet0/0
10.0.0.9 IRDP 8 - 10 FastEthernet0/0
Default gateway is 10.0.0.3
This archive was generated by hypermail 2.1.4 : Mon Feb 02 2004 - 09:07:38 GMT-3