From: Peter Van Oene (pvo@xxxxxxxxxxxx)
Date: Wed Aug 15 2001 - 14:43:20 GMT-3
First of all, when dealing with direct reachability information, OSPF does not
advertise networks at all. OSPF advertises links and their associated qualitie
s and other intra area routers figure out network reachability. Hence, your qu
estion isn't really valid. The network statement in OSPF is used as a tool for
indicating which interfaces will participate in the OSPF process. Using a ran
ge of addresses simply allows you to specific more than one interface with a si
ngle network statement. I personally use the direct mask of 0.0.0.0 for all ne
twork statements.
In your example, the entry in the type 1 LSA for that interface is the same for
both options. Only summary advertisements (3/5/7) contain information about s
pecific prefix reachability.
*********** REPLY SEPARATOR ***********
On 8/15/2001 at 10:11 AM Jeffrey Levine wrote:
>I have noticed in some lab scenarios that when the instructions say that
>a
>router interface should be advertised in a routing protocol, the labs
>sometimes advertise only the interface, othertimes an entire subnet.
>
>For example, let's say it's an ethernet interface with address
>192.168.1.1/24 being advertised under OSPF. I've seen the following:
>
>router ospf 64
>net 192.168.1.1 0.0.0.0 area 0
>
>or
>
>router ospf 64
>net 192.168.1.1 0.0.0.255 area 0
>
>I wouldn't be concerned if there were some consistency. I've seen the lab
>instructions state "interface" and then seen the entire network advertised
>and vice-versa.
>
>Any thought?
>
>Jeffrey S. Levine
>
>
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