From: Brian Dennis (brian@labforge.com)
Date: Sun May 25 2003 - 03:20:12 GMT-3
It's not good practice but you can have as many area 1's as you want.
<RFC2328>
3.7. Partitions of areas
OSPF does not actively attempt to repair area partitions. When
an area becomes partitioned, each component simply becomes a
separate area. The backbone then performs routing between the
new areas. Some destinations reachable via intra-area routing
before the partition will now require inter-area routing.
However, in order to maintain full routing after the partition,
an address range must not be split across multiple components of
the area partition. Also, the backbone itself must not
partition. If it does, parts of the Autonomous System will
become unreachable. Backbone partitions can be repaired by
configuring virtual links (see Section 15).
</RFC2328>
In your case you need to make sure that you don't end up with two area
0's if the Ethernet's become "disconnected". If one Ethernet actually
goes "down" and the BRI calls, then you are okay. Also if you are using
a virtual link make sure you take into consideration the possibility of
one of the Ethernet interfaces going down. The reason being is that the
router would cease to be an area 0 router anymore.
Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
-----Original Message-----
From: Ciscolab [mailto:ciscolab@vip.sina.com]
Sent: Saturday, May 24, 2003 10:01 PM
To: ccielab@groupstudy.com; brian@labforge.com
Subject: discontinuous OSPF Area
Importance: High
ccielabHello, Group,
I have the following topology, R1 and R2 is in ospf area 0 and with ISDN
backup area 1, when ISDN interface of both is do
wn, the area 1 is splitted, is it working well ? any comments, thanks
for your input.
R1(e0)<-----area 0----->(e0)R2
\ /
(Bri0)<---area 1--->(Bri0)
$B!!!!!!!!!!!!!!!!(BCiscolab
$B!!!!!!!!!!!!!!!!(Bciscolab@vip.sina.com
$B!!!!!!!!!!!!!!!!!!!!(B2003-05-25
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