3com S7906E Manuel De Montage

 

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Specify a cost for the default 
route advertised to the NSSA 
area 

default-cost cost 

Optional 

Defaults to 1. 

 

z 

It is required to use the nssa command on all the routers attached to an NSSA area. 

z 

Using the default-cost command only takes effect on the ABR/ASBR of an NSSA area. 

 

Non-backbone areas exchange routing information via the backbone area. Therefore, connectivity 

between the backbone and non-backbone areas and within the backbone itself must be maintained. 

If necessary physical links are not available for this connectivity maintenance, you can configure virtual 

links to solve it. 

Follow these steps to configure a virtual link: 

Enter system view 

— 

Enter OSPF view 

ospf [ process-id | router-id 
router-id | vpn-instance 
instance-name ] * 

— 

Enter area view 

area area-id

 

— 

Configure a virtual link 

vlink-peer router-id [ hello 
seconds | retransmit seconds | 
trans-delay seconds | dead 
seconds | simple [ plain | 
cipher ] password | { md5 | 
hmac-md5 } key-id [ plain | 
cipher ] password ] * 

Required 

You need to configure this 
command on both ends of a 
virtual link. 

Note that hello and dead 
intervals must be identical on 
both ends of the virtual link. 

 

OSPF classifies networks into four types: broadcast, NBMA, P2MP, and P2P, upon the link layer 

protocol. 

z 

Broadcast: When the link layer protocol is Ethernet or FDDI, OSPF considers the network type as 

broadcast by default.  

z 

NBMA: When the link layer protocol is Frame Relay, ATM or X.25, OSPF considers the network 

type as NBMA by default.