From: Kenneth Wygand (KWygand@customonline.com)
Date: Fri Jan 30 2004 - 14:53:24 GMT-3
Iwan,
You said:
"What I also want to do is to use the PATH of frame relay, so I need to
set the route that the ISDN link uses to a higher AD then what frame
relay uses..."
This is not true. OSPF metrics are based on the bandwidth of the link.
I don't remember what the autoconfigured bandwidth is of an ISDN link,
but either way your Frame Relay interface is serial so it will default
to 1.544mbit bandwidth unless you specifically set the bandwidth
differently with the "bandwidth" command.
As a result, when both links are up, the OSPF protocol will give the
ISDN link a higher metric, so it will NOT be used when the frame relay
link is up. You do not have to set an Administrative Distance to
accomplish this.
Then to keep the link down, all you need to do is run "IP OSPF
DEMAND-CIRCUIT" on the ISDN interface (only on ONE side of the link!).
Be careful though. Make sure to use the command "no peer
neighbor-route" on both ISDN interfaces, otherwise disconnect will
remove the /32 PTP route from the routing table, causing a topology
change, and causing the OSPF Demand-circuit to kick the link up again!
Hope this helps!
Kenneth E. Wygand
Systems Engineer, Project Services
CISSP #37102, CCNP, CCDP, ACSP, Cisco IPT Design Specialist, MCP, CNA,
Network+, A+
Custom Computer Specialists, Inc.
"Success is to be measured not so much by the position one has reached
in life as by the obstacles which he has overcome while trying to
succeed."
-Booker Taliaferro Washington
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
iwan
Sent: Friday, January 30, 2004 9:01 AM
To: ccielab@groupstudy.com
Subject: ISDN question
Hi,
I have 2 routers in 1 OSPF area connected with frame relay...
These 2 routers are also connected to ISDN for backup...
This is the task:
I want to configure ISDN backup for the frame relay connection.
I do NOT want to use:
- Dialer backup interface command
- Dialer watch
This leaves me with 2 options
- Static floating route
- OSPF demand circuit
My question here is:
I want to use OSPF demand circuit...
I know that OSPF demand circuit is mainly used to suppress the hello
messages from OSPF so that the ISDN link won't come up because of
that...
What I also want to do is to use the PATH of frame relay, so I need to
set the route that the ISDN link uses to a higher AD then what frame
relay uses...
How do I accomplish this?
The CCIE LAB won't permit the static floating route...
And I am not sure if this is accomplished by defining the demand circuit
ONLY.
Iwan Hoogendoorn
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