From: Marko Milivojevic (markom@vodafone.is)
Date: Thu Jun 14 2007 - 10:27:56 ART
[ http://www.cisco.com/warp/public/104/9.html#q27 ]
Q. Can I control the P-bit when importing external routes into a not-so-stubby area (NSSA)?
A. When external routing information is imported into an NSSA in a type 7 link-state advertisement (LSA), the type 7 LSA has only area flooding scope. To further distribute the external information, type 7 LSAs are translated into type 5 LSAs at the NSSA border. The P-bit in the type 7 LSA Options field indicates whether the type 7 LSA should be translated. Only those LSAs with the P-bit set are translated. When you redistribute information into the NSSA, the P-bit is automatically set. A possible workaround applies when the Autonomous System Boundary Router (ASBR) is also an Area Border Router (ABR). The NSSA ASBR can then summarize with the not-advertise keyword, which results in not advertising the translated type 7 LSAs.
Another approach that could be of some use is to configure "OSPF Inbound Filtering Using Route Maps":
http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cg/hirp_c/ch15/hroutma.htm
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Ajay Prakash
Sent: 14. jznm 2007 13:03
To: Cisco certification
Cc: Ajay
Subject: How to set the P-bit
Hello,
Is there is way to change the P-bit while distributing External routes into
OSPF NSSA so that the type 7 LSA does not cross the ABR to the rest of the
OSPF AS as a type 5 LSA? The book i reffered to says that the P-bit is
automatically set to 1 while re-distributing into NSSA. How can we change this
default behaviour?
Thanks :)
Ajay
This archive was generated by hypermail 2.1.4 : Sun Jul 01 2007 - 17:24:49 ART