Subject: OSPFv3 and Cost configured on loopback interface

From: Santosh Esale <[email-masked]>
Date: Tue, 21 Sep 2004 11:03:10 +0530

Hi ,

     I was reading the RFC 2740 and had a question regarding the setting of
cost for ospfv3 routes configured on loopback interface.

RFC 2740section 3.4.3.7. says -

RTX adds the IPv6 prefixes for any directly attached hosts

      belonging to the area (see Section C.7) to the intra-area-prefix-

      LSA

   o  If RTX has one or more virtual links configured through the area,

      it includes one of its site-local or global scope IPv6 interface

      addresses in the LSA (if it hasn't already), setting the LA-bit in

      the PrefixOptions field, and setting the PrefixLength to 128 and

      the Metric to 0. This information will be used later in the

      routing calculation so that the two ends of the virtual link can

      discover each other's IPv6 addresses.

Now if I have configured ipv6 global address on loopback interface  and this
router has only p2p links to transit area , Then we need to orginate
intra-prefix LSA for this loopback address with LA bit set and cost set to 0
.

so does it mean the cost configured on loopback interface should not be used
while advertising in intra-prefix LSA and downloading the route to RIB??

Thanks in advance

santosh

---

From: Acee Lindem <[email-masked]>
Date: Tue, 21 Sep 2004 09:08:29 -0400

Hi Santosh,

Functionally, I don't see any problem with allowing a loopback cost to be configurable.
In fact, my implementation allows this. 

Hope this helps, 
Acee
  ----- Original Message ----- 
  From: Santosh Esale 
  To: [email-masked] 
  Sent: Tuesday, September 21, 2004 1:33 AM
  Subject: OSPFv3 and Cost configured on loopback interface

  Hi ,

       I was reading the RFC 2740 and had a question regarding the setting of cost for ospfv3 routes configured on loopback interface.

        LSA

  Now if I have configured ipv6 global address on loopback interface  and this router has only p2p links to transit area , Then we need to orginate intra-prefix LSA for this loopback address with LA bit set and cost set to 0 .

  so does it mean the cost configured on loopback interface should not be used while advertising in intra-prefix LSA and downloading the route to RIB??

  Thanks in advance 

  santosh