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Configuring Trunks
Configuring VNN OSPF
ATM Services Configuration Guide for CBX 3500, CBX 500, GX 550, and B-STDX 9000 1/19/057-47
Configuring VNN OSPF
Lucent switches can perform routing tasks using IP and VNN routing software. Both 
IP and VNN support the OSPF routing protocol. In previous releases of Lucent switch 
software, VNN and IP shared the same OSPF software component to perform their 
OSPF routing tasks. However, VNN and IP now have their own OSPF software 
components, or instances. These instances are called VNN OSPF and IP OSPF.
VNN OSPF is supported in Lucent switches that are configured as autonomous system 
border routers (ASBRs). In an autonomous system (AS) each switch belongs to an 
area. Switches configured as ASBRs exchange routing information with other ASs via 
external gateway routing protocols, such as Border Gateway Protocol (BGP). The 
external route information collected through these protocols is then aggregated and 
flooded through the AS.
VNN OSPF is typically configured over Lucent trunks. This section describes how to 
configure loopback addresses, area aggregates, external route aggregates, and virtual 
links for VNN OSPF. It also describes how to configure VNN OSPF optimized 
flooding and VNN OSPF Name link state advertisement (LSA) suppression, which 
enhance VNN OSPF performance.
Configuring VNN OSPF Loopback Addresses
To configure a VNN OSPF loopback address for a GX 550 or CBX 500 switch:
1. Expand the instance node for the switch to which you want to add a VNN OSPF 
loopback address.
2. Expand the VNN class node.
3. Right-click on the VNN Loopback Addresses class node and select Add from the 
pop-up menu.
The Add VNN Loop back Address dialog box appears (Figure 7-19).
Note  – For details about how IP OSPF and VNN OSPF interoperate, as well as 
step-by-step configuration procedures for IP OSPF, see the IP Services Configuration 
Guide for CBX 3500, CBX 500, and B-STDX 9000.