From: Buddy Venne (Buddy.Venne@xxxxxxxxxx)
Date: Fri Mar 02 2001 - 22:16:42 GMT-3
Chuck -
I hope I am not too late for the Friday fun. I followed most of the thread
and then built a lab to answer the question. my results show E1 is
preferred. I made these equal-cost of 20. If I filter the E1, then the E2
route will be put in the routing table after a clear. See this display of
how each of these routes appear in the ospf database (note the text after
the metric type):
chipweyanR7#sho ip osp dat ext 134.12.80.0
OSPF Router with ID (138.10.107.7) (Process ID 89)
Type-5 AS External Link States
Routing Bit Set on this LSA
LS age: 951
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 134.12.80.0 (External Network Number )
Advertising Router: 134.12.106.6
LS Seq Number: 80000006
Checksum: 0xF6A7
Length: 36
Network Mask: /24
Metric Type: 1 (Comparable directly to link state metric)
TOS: 0
Metric: 20
Forward Address: 134.12.1.4
External Route Tag: 0
Routing Bit Set on this LSA
LS age: 1552
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 134.12.80.0 (External Network Number )
Advertising Router: 206.11.7.1
LS Seq Number: 80000003
Checksum: 0x36A3
Length: 36
Network Mask: /24
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 0.0.0.0
External Route Tag: 0
chipweyanR7#
Buddy Venne, MCSE, CCNP Security Specialist
WAN/LAN Specialist
Onyx Acceptance Corp.
(949) 465-3775
-----Original Message-----
From: Chuck Larrieu [mailto:chuck@cl.cncdsl.com]
Sent: Thursday, March 01, 2001 10:07 PM
To: CCIE_Lab Groupstudy List
Subject: Friday Follies Returns - OSPF route preference
A less fun reprise of my once famous Friday Follies questions:
Given the following information, which route will ospf prefer, and therefore
place into the routing table?
a) E1 ( external type 1 ) with a cost of 84
b) E2 ( external type 2 ) with a cost of 20
For extra credit - why?
( I don't know either and I can't find a good explanation on the doc CD )
( but this time I have traces and captures to prove the point )
Chuck
----------------------
I am Locutus, a CCIE Lab Proctor. Xx_Brain_dumps_xX are futile. Your life as
it has been is over ( if you hope to pass ) From this time forward, you will
study US!
( apologies to the folks at Star Trek TNG )
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