HP 5500 Ei 5500 Si Switch Series Configuration Guide

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BFD 
Bidirectional forwarding detection (BFD) provides a single mechanism to quickly detect and monitor the 
connectivity of links between OSPF neighbors, reducing network convergence time. For more information 
about BFD, see  High Availability Configuration Guide . 
Protocols and standards 
•  RFC 1765,  OSPF Database Overflow  
•   RFC 2328,  OSPF Version 2  
•   RFC 3101,  OSPF Not-So-Stubby Area (NSSA) Option  
•   RFC 3137,  OSPF Stub Router Advertisement  
•   RFC 3630,  Traffic Engineering...

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Task  Remarks 
Configuring OSPF preference Optional 
Configuring OSPF route redistribution Optional 
Tuning and optimizing 
OSPF networks Configuring OSPF packet timers 
Optional 
Specifying LSA transmission delay Optional 
Specifying SPF calculation interval Optional 
Specifying the LSA arrival interval Optional 
Specifying the LSA generation interval Optional 
Disabling interfaces from receiving and sending OSPF 
packets Optional 
Configuring stub routers 
Optional 
Configuring OSPF authentication...

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Configuration procedure 
To enable OSPF on a router, create an OSPF process and specify areas with which the process is 
associated, and the network segments contained in each area. If an interface’s IP address resides on a 
network segment of an area, the interface belongs to the area and is enabled with OSPF, and OSPF 
advertises the direct route of the interface. 
To run OSPF, a router must have a router ID, which is the unique identifier of the router in the AS. 
Following is additional...

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Configuring OSPF areas 
After splitting an OSPF AS into multiple areas, configure some areas as stub areas or NSSA areas as 
needed.  
If no connection can be achieved between the backbone and a non-backbone area, or within the 
backbone itself, you can configure virtual links to solve it. 
Configuration prerequisites 
Before you configure an OSPF area, complete the following tasks: 
•  Configure IP addresses for interfaces, and make sure that all neighboring nodes can reach each 
other at the...

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 NOTE: 
Virtual links cannot transit totally stub areas.  
Configuring an NSSA area 
A stub area cannot redistribute routes. Configur e the area as an NSSA area to allow for route 
redistribution by keeping other stub area characteristics. 
To configure an NSSA area: 
 
Step Command Remarks 
1.   Enter system view. 
system-view  N/A 
2.  Enter OSPF view.  ospf 
[ process-id  | router-id  
router-id  | vpn-instance  
vpn-instance-name  ] *  N/A 
3.
  Enter area view.  
area area-id
  N/A 
4....

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Step Command Remarks 
4.  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  ] *  You must configure this command on 
both ends of a virtual link. 
hello
 and  dead intervals must be 
identical on both ends of the virtual 
link. 
 
Configuring OSPF network types 
OSPF classifies networks into the foll owing types by...

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Step Command Remarks 
3.  Configure the OSPF network 
type for the interface as 
broadcast.   ospf network-type broadcast  By default, the network type of an 
interface depends on the link layer 
protocol.
 
4.  Configure a router priority for 
the interface.  ospf dr-priority
 priority  Optional. 
The default router priority is 1. 
 
Configuring the OSPF network ty
pe for an interface as NBMA 
After configuring the network type of an interface as NBMA, you must make some special configurations....

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Step Command Remarks 
2.  Enter interface view.  interface
 interface-type 
interface-number   N/A 
3.
  Configure the OSPF network 
type for the interface as 
P2MP.  ospf network-type p2mp
 [ unicast ]
 
By default, the network type of an 
interface depends on the link layer 
protocol.  
After you configure the OSPF 
network type for an interface as 
P2MP unicast, all packets are unicast 
over the interface. The interface 
cannot broadcast hello packets to 
discover neighbors. In that case, you...

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Configuring OSPF route summarization 
Ro u t e  s u m m a riza t io n  i s  wh e n  a n  A B R  o r  AS B R  s u m m a rize s  ro u te s  wi t h  t h e  s a m e  p re fix  i n t o  a  s i n g l e  ro u t e  
and distributes it to other areas. 
Route summarization reduces the traffic of routing information exchanged between areas and the sizes 
of routing tables on routers, improving route calculation speed on routers. 
For example, there are three internal routes in an area: 19.1.1.0/24,...

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Configuring OSPF inbound route filtering 
O S P F  c a l cu l a t e s  ro u t e s  by  u s i n g  L SA s .  T h e  c a l c u l a t e d  routes can be filtered and only permitted routes are 
installed into the OSPF routing table. 
OSPF provides the following filtering methods: 
•   Filters routing information by destination address through ACLs and IP address prefixes 
•   Filters routing information by next hop through the filtering criteria configured with the  gateway 
keyword 
•   Filters routing...