You can refer following documents.
http://www.cisco.com/public/cons/isp/documents/loopback.pdf
-Mansu kim
Thrunet co.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of James
Xie
Sent: Thursday, June 08, 2000 2:39 PM
To: [EMAIL PROTECTED]
Subject: Re: Loopback Address
Loopback is a virtual inteface on the router. It
is up all the time.
There are some routing prototocols require a router ID
such as OSPF and BGP. If you use a phyical interface's
ip address as the router's ID, when that physical interface
goes down, the routing adjacency will change/break. In the
OSPF case, right after the reboot, when all the physical
interfaces are not up yet (keepalive have not been exchanged),
the OSPF process may not start at all, because no router ID
is available yet.
Another usage is, when you use unnumber layer 3 addresses,
sometime, you want to test the reachability to the router,
you can use the loopback interface address for this purpose.
You can also use loopback interface for testing purposes. Such
as, define a bouch of layer 3 networks on the lookback interfaces
(you can have multiple loopback interfaces on a router)
and test the routing protocols and updates etc.
You can also use lookup interface to perform routing load balance:
S0 S0
R1 =========== R2
S1 S1
On the routers you can setup static routes with the next hop addressed to
the loopback interface address on the other router. Since the router has
two paths to that loopback interface, therefore you can reach the next hop
using two paths. This static route can be useful, for example, in the case
of BGP routing etc.
You can also use loopback interface to perform debug without affect any
physical connection. Such as observe routing updates etc.
That's all I can think about. Maybe others can add more..
Jim Xie
International Network Service.
At 08:49 AM 06/08/2000 +0700, Distiawan wrote:
>
> Dear Netters,
> I don't really understand what is Loopback Address used for ?
> Is there any body can explain it to me more detail ?
> Tx
___________________________________
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
___________________________________
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
