Controlling External Routes Advertised In An Nssa Area; Figure 12: Controlling External Routes (Nssa Area) - Avaya 8600 Engineering

9.3 Controlling External Routes Advertised in an
NSSA Area
In an OSPF NSSA area, the NSSA N/b-bit in the Options field of OSPF Hello packets is used to tell the
border router what external routes can be advertised to other areas. The NSSA N/p-bit, if set, tells the
area border router to export the external route. This is the default behavior with the Ethernet Routing
Switch 8600. Otherwise, if not set, it informs the area border router to drop the external route. A route
policy can be created on the Ethernet Routing Switch 8600 manipulate the N/p-bit.
In this configuration example, there is a RIP network inside the NSSA Area 2. We would like to only
advertise the 15.15.15.0/24 network to Area 0. The following are the configuration step required on
PP8600E:

Enable PP8600E as an OSPF ASBR

Create NSSA Area 2

Create a Route Policy to advertise OSPF and direct interfaces to RIP

Create a Route Policy to only advertise RIP network 15.15.15.0/24 to Area 0 by using the NSSA
N/p-bit
Step 1 Configure RIP Interface
config ethernet 1/48 ip create 20.1.1.2/30
2091
config ethernet 1/48 ip rip enable
Step 2 Enable RIP Globally and Configure RIP Interface for RIPv2
config ip rip enable
config ip rip interface 20.1.1.2 send-mode
rip2
config ip rip interface 20.1.1.2 receive-
mode rip2
November 2010

Figure 12: Controlling External Routes (NSSA Area)

ERS 8600 / 8800 OSPF Technical Configuration Guide
These two command configure port 1/48 as a brouter
port and enables RIP on this interface
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