From: Schulz, Dave (DSchulz@dpsciences.com)
Date: Tue Jul 12 2005 - 08:51:30 GMT-3
Is this true that sequence matters....or, is it because OSPF will match the
any specific entry in the net statements. If no specific entry, then it takes
the first match? I believe that most of the protocols will do this. Just a
thought for discussion purposes.
Dave
-----Original Message-----
From: nobody@groupstudy.com
To: ccie2be; 'Chris Aguillo'; 'Godswill Oletu'; 'ccie_06';
ccielab@groupstudy.com
Sent: 7/12/2005 5:12 AM
Subject: Re: OSPF Network Statement
I guess you are r right Tim. IOS has gotten smarter. I am sure that I
read
it somewhere that new IOS will not consider the sequence now.
Though I also have not tested also but new IOS works that way.
Amit
----- Original Message -----
From: "ccie2be" <ccie2be@nyc.rr.com>
To: "'Chris Aguillo'" <ccaguillo1@hotpop.com>; "'Godswill Oletu'"
<oletu@inbox.lv>; "'ccie_06'" <ccie_06@att.net>;
<ccielab@groupstudy.com>
Sent: Tuesday, July 12, 2005 11:28 AM
Subject: RE: OSPF Network Statement
> Chris,
>
> Has IOS gotten smarter?
>
> It used to be that if the first network statement included 0.0.0.0
> 255.255.255.255, that was it. No other statements mattered. I haven't
> tested this myself but it used to be that the sequence of net
statements
> mattered.
>
> Tim
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Chris Aguillo
> Sent: Tuesday, July 12, 2005 12:55 AM
> To: Godswill Oletu; ccie_06; ccielab@groupstudy.com
> Subject: OSPF Network Statement
>
> Hi ccie_06,
>
> upon you start the OSPF process, the algorithm will check which
> interface is part of an OSPF area or not.
>
> Each NETWORK command is treated sequentially as it is written under
the
> ROUTER OSPF command.
>
> Also in each every NETWORK ip_address inverse_mask command, you will
> treat it as it is an ACL.
>
> taking out from your original script:
>
> network 0.0.0.0 255.255.255.255 area 0
> >>> 0.0.0.0 255.255.255.255 means all IP-Address will match
> >>> any interface that have a valid IP address and will be placed in
Area0
>
> network 1.2.3.0 0.0.0.0 area 1
> >>> The IP address 1.2.3.0 is a host address as per inverse_mask
> >>> The Interface that have the IP address of 1.2.3.0 is pulled out
> from area 0 and placed into area 1.
>
>
> network 1.2.3.4 0.0.0.0 area 2
> >>> The IP address 1.2.3.4 is a host address as per inverse_mask
> >>> The Interface that have the IP address of 1.2.3.4 is pulled out
> from area 0 and placed into area 2
>
> As a result, all router interfaces are in Area 0 except 1.2.3.0 and
> 1.2.3.4 which are in Area 1 and Area 2 respectively.
>
> Moreover, reversing the Network statement and placing as the last
> statement the command
>
> NETWORK 0.0.0.0 255.255.255.255 AREA 0
> >>> this will remove all interfaces assigned in other Areas (earlier
> NETWORK command) and will bring other interfaces not yet assigned for
> any Area and all be brought into AREA 0.
>
> >>> This is in effect because the Network command is treated
sequencially.
>
> I do not see why network 1.2.3.0 0.0.0.0 will not match any interface
> and no interface as a result will be in AREA 1 as per Godswill below?
> >>> as long as there is a valid IP_address configured in the router
as
> 1.2.3.0, that only interface will be placed in AREA 1.
>
> I do not agree with the explanation of Godswill for:
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> network 0.0.0.0 255.255.255.255 area 0 -> Will match ALL remaining
> interfaces not previously matched and place them into area 0.
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> The network command is placed as the first item in the series of
Network
> command, thus it will make all interface in the area 0 (whether or not
> matched in other network command, take note this network is the first
> one). The way I analyzed the words <<<all remaining>>> and <<<not
> previously mathed>>> is probably he thinks that Network Command is not
> trated sequentially.
>
> HTH....chris
>
>
> Godswill Oletu wrote:
> > The interfaces will be assigned like this:
> > network 1.2.3.0 0.0.0.0 area 1 -> Will not match any interface, no
> > interface will be in area 1
> >
> > network 1.2.3.4 0.0.0.0 area 2 -> Will match only interface 1.2.3.4
and
> > put it into area 2
> >
> > network 0.0.0.0 255.255.255.255 area 0 -> Will match ALL remaining
> > interfaces not previously matched and place them into area 0.
> >
> > Thanks.
> > Godswill Oletu
> >
> > ----- Original Message ----- From: "ccie_06" <ccie_06@att.net>
> > To: <ccielab@groupstudy.com>
> > Sent: Sunday, July 10, 2005 12:29 PM
> > Subject: Ospf Network statement
> >
> >
> >> Can any one explain following statement under ospf process ( I
mean
> >> which interface will participate in which area.?)
> >>
> >> router ospf 1
> >> network 0.0.0.0 255.255.255.255 area 0
> >> network 1.2.3.0 0.0.0.0 area 1
> >> network 1.2.3.4 0.0.0.0 area 2
>
>
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