router ospf 100 <- fails 2

[netprogrammer]

When I try to install the ospf routing protocol on my Cisco 2610 with IOS Version 12.0(5), I get an error "Could not allocate router ID". I have tried all sorts of things, what am I doing wrong?


Router(config)#interface ethernet 0/0
Router(config-if)#ip address 10.0.0.6 255.0.0.0
Router(config-if)#router ospf 100

OSPF: Could not allocate router id

 

[ADB100]

With OSPF each Router has a Router ID (RID). This is visible when you issue the command 'show ip ospf neighbor' It will show the neighbours RID and the Interface IP address it 'sees' the OSPF router on. By default a Cisco router will use the Highest Loopback interface IP address as the RID, if there are no Loopback interfaces then it will use the Highest physical interface IP address that is in the UP state - if you don't have any interfaces that are UP and are configured for IP then OSPF won't start. The recommended way of running OSPF is to allocate a Loopback interfaces to all your routers. This is normally done using /32 masks so you don't waste valuable IP address space, also you can keep all the Loopback IP addresses contiguous so you can easily identify them.
Loopback interfaces are also recommended when using NMS systems as well - source IP address for SNMP traps, TACACS+ & RADIUS, Syslog etc etc. Loopback interfaces never go down unless they are removed, unlike physical interfaces that can down as a result of a fault etc.

Andy

 

[mainstreetexpress]

Hi
All you want to do is get OSPF running correct?
ADB100 is correct with respect to the interfaces etc but what you seem to have done wrong is that you have tried to initiate OSPF whilst in the interface sub command mode

try this

Router(config)#interface ethernet 0/0
Router(config-if)#ip address 10.0.0.6 255.0.0.0
Router(config-if)#exit
Router(config)#router ospf 100
Router(config-router)#network x.x.x.x x.x.x.x area x

Cheers

Mark

 

[vipergg]

Agree with other poster you don't start ospf at the interface level , done at the global level .

 

[netprogrammer]

Thank you to both Andy and Mark. The main problem was that I had no IP interfaces 'UP', tha't why I got the "Could not allocate router id" message. I had tried that both with and without being in the interface sub-command mode. Now ospf runs, and I have configured an Ethernet interface and a ppp serial interface for ospf, but they are not yet talking for some reason. I may have a numbered interface at one and and an un-numbered on the cisco end.

Thanks again!!

 

[baddos]

The IOS will allow you to enter global commands from interface configuration mode, and is smart enough to take you to the root of the configuration.