From: Lee Donald (Lee.Donald@t-systems.co.uk)
Date: Tue Apr 19 2005 - 16:34:39 GMT-3
Gladston,
ISDN interfaces in OSPF have a much higher cost than ser interfaces.
The cost for your isdn should be 1562, so there must be another reason it
prefers the isdn path.
In the database it doesn't show this route from the ser int?
-----Original Message-----
From: gladston@br.ibm.com [mailto:gladston@br.ibm.com]
Sent: Tuesday, April 19, 2005 6:28 PM
To: ccielab@groupstudy.com
Subject: OSPF - Prefered External Path - Avoid ISDN
R5 receives external LSA about route 200.200.47.0 from R4 (BRI) and from R1
(serial).
Is there a way to configure R5 so it prefer path R5---R1 to reach net
200.200.47.0, instead path R5----R4 (bri)?
R4(bri)----OSPF A300---(bri)R5(s0/0)----OSPF A0----(s0/0)R1(s0/0.14)
| |
|___________________________OSPF A200_________________________|
It seems there is a problem with R4, because it is connected to two areas
(area 300 and area 200) while not connected to area0. Would you agree? Even
though I configure virtual link on R4--R5, this way connecting R4 to area 0,
would you have a solution to the first question? (R5 should prefer the path
to R1 to reach the external network injected by R4 instead of the directly
path to R4 (BRI).
show ip ospf database external 200.200.47.0
200.200.47.0 142.20.4.1 294 0x80000005 0x006142 0
Rack2R5#sir 200.200.47.0
Routing entry for 200.200.47.0/24
Known via "ospf 1", distance 110, metric 1582, type extern 1
Redistributing via eigrp 10
Advertised by eigrp 10 metric 10000 1000 255 1 1500
Last update from 200.20.45.5 on BRI0/0, 00:05:41 ago
Routing Descriptor Blocks:
* 200.20.45.5, from 200.20.4.1, 00:05:41 ago, via BRI0/0
Route metric is 1582, traffic share count is 1
Rack2R5#sh ip os border-routers
OSPF Process 1 internal Routing Table
Codes: i - Intra-area route, I - Inter-area route
i 200.20.4.1 [1562] via 200.20.45.5, BRI0/0, ASBR, Area 113, SPF 23
Rack2R5#conf t
int bri 0/0
shutdown
Rack2R5#sir 200.200.47.0
Routing entry for 200.200.47.0/24
Known via "ospf 1", distance 110, metric 148, type extern 1
Redistributing via eigrp 10
Advertised by eigrp 10 metric 10000 1000 255 1 1500
Last update from 200.20.125.1 on Serial0/0, 00:00:03 ago
Routing Descriptor Blocks:
* 200.20.125.1, from 200.20.4.1, 00:00:03 ago, via Serial0/0
Route metric is 148, traffic share count is 1
Rack2R5#sh ip os border-routers
OSPF Process 1 internal Routing Table
Codes: i - Intra-area route, I - Inter-area route
I 200.20.4.1 [128] via 200.20.125.1, Serial0/0, ASBR, Area 0, SPF 31
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