From: P729 (p729@xxxxxxx)
Date: Sat Jun 29 2002 - 19:05:30 GMT-3
Nothing in the config guide will lead you to believe there is any difference
between using a wildcard mask vs. using an explicit one in the 'network'
command. But beware:
CSCdm75819 - If OSPF is configured using a ''network x.x.x.x 0.0.0.0 area
x'' command (explicitly identifying and (sic) interface), then the connected
interface information may not be properly redistributed into other protocols
(configured to ''redistribute ospf xxx...''). Workaround: use a general mask
instead (''network x.x.x.0 0.0.0.255 area x'', for example). Found in:
11.2(18), 12.0(5); Fixed in: 12.0(8.00.02)T, 12.0(8.00.02)PI, 12.0(13.5)S,
12.0(13.6)ST.
CSCdu34902 - OSPF may send external LSAs with zero forwarding address
instead of non-zero forwarding address. This is a configuration issue and
can happen if complete interface address and zero mask is specified in
network command under "router ospf". Workaround is to specify subnet address
and mask in the network command. First found in: 12.1(8.1); Fixed in:
12.2(5.8)T, 12.2(5.8)PI, 12.2(6.4)PB, 12.2(6.4)B.
Regards,
Mas Kato
https://ecardfile.com/id/mkato
----- Original Message -----
From: "Harish DV/peakxv" <harish.dv@peakxv.net>
To: "Ahmed Al-Ghawas" <ghawas@batelco.com.bh>
Cc: <ccielab@groupstudy.com>; <nobody@groupstudy.com>
Sent: Saturday, June 29, 2002 1:55 PM
Subject: Re: OSPF wildcard bits
> Ahmed,
>
> There is no difference between the 2 methods. However, defining the
> wildcard bits with the whole subnet (ex. 0.0.0.255) will be usefull in
some
> cases.
> Lets take an example:
>
> Assume Router R 1 has 3 interfaces under ospf.
> Int 1 is in ospf area 0 (ip add 172.16.1.1/24)
> Int 2 and 3 are in ospf area 1 (ip add 172.16.2.1/24 and 172.16.3.1/24
> respectively)
>
> Now under ospf: - there are 2 ways of configuring this
>
> 1st method
> router ospf <pro id>
> network 172.16.1.1 0.0.0.0 area 0
> network 172.16.2.1 0.0.0.0 area 1
> network 172.16.3.1 0.0.0.0 area 1
>
> 2nd method
> router ospf <pro id>
> network 172.16.1.1 0.0.0.0 area 0
> network 172.16.0.0 0.0.255.255 area 1 (you are avoiding configuring
> multiple entries)
>
> Pls note that the order of the network statements does matter!. For ex. In
> the 2nd method, if you reverse the order of the network statements, ospf
> will not consider 172.16.1.1 under area 0 because 172.16.0.0 matches it
and
> you will have problems!.
>
> HTH
>
> Harish
>
>
>
>
> "Ahmed Al-Ghawas"
> <ghawas@batelco.c To:
<ccielab@groupstudy.com>
> om.bh> cc:
> Sent by: Subject: OSPF wildcard
bits
> nobody@groupstudy
> .com
>
>
> 06/29/2002 12:36
> PM
> Please respond to
> "Ahmed Al-Ghawas"
>
>
>
>
>
>
> Guys,
>
> I am really getting confused!
>
> From what I understood from "CCIE Practical Studies" book that when using
> the
> network command, that you ought to be precise in the extent that you would
> add
> the interface ip address and not advertise the whole subnet mask!
>
> For example:
>
> R1
> S0:10.1.128.1/24
> |
> |
> S0:10.1.128.2/24
> R2
> S1:10.1.80.1/24
> |
> |
> S1:10.1.80.3/24
> R3
>
> R1 config:
> router ospf 2001
> network 10.1.128.1 0.0.0.0 area x (and not; network 10.1.128.0 0.0.0.255
> area
> x!!)
>
> R2 config:
> router ospf 2001
> network 10.1.128.2 0.0.0.0 area x (and not; network 10.1.128.0 0.0.0.255
> area
> x!!)
> network 10.1.80.1 0.0.0.0 area x (and not; network 10.1.80.0 0.0.0.255
area
> x!!)
>
> R3 config:
> router ospf 2001
> network 10.1.80.3 0.0.0.0 area x (and not; network 10.1.80.0 0.0.0.255
area
> x!!)
>
> I really need to stick to one concept and understand why this book doest
it
> differently then the other and avoid loosing marks for such stupid thing
in
> the real lab!!
>
> Any input is much appreciated
>
> Ahmed
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