Configuring Ospf Network Optimization; Prerequisites; Configuring Ospf Packet Timers - 3Com MSR 50 Series Configuration Manual

946 C 58: OSPF C
HAPTER
Configuring OSPF
Network Optimization

Prerequisites

Configuring OSPF Packet
Timers
ONFIGURATION
To do...
Configure the default values
of parameters for
redistributed routes (cost,
route number, tag and type)
n
Using the import-route command cannot redistribute a default external
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route. To do so, you need to use the default-route-advertise command.
The default-route-advertise summary cost command is applicable only to
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VPN, and the default route is redistributed in a Type-3 LSA. The PE router will
advertise the default route to the CE router.
By filtering redistributed routes, OSPF translates only routes, which are not
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filtered out, into type5 LSAs or type7 LSAs for advertisement.
You can configure default values of parameters for redistributed routes, such
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as the cost, upper limit, tag and type of external routes. The tag is used to
indicate information related to protocol, for example, when redistributing BGP
routes, OSPF uses the tag to differentiate AS IDs.
You can optimize your OSPF network in the following ways:
Change values of OSPF packet timers to adjust the OSPF network convergence
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speed and network load. On low speed links, you need to consider the delay
time for sending LSAs on interfaces.
Change the interval for SPF calculation to reduce resource consumption caused
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by frequent network changes.
Configure OSPF authentication to meet high security requirements of some
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mission-critical networks.
Configure OSPF network management functions, such as binding OSPF MIB
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with a process, sending trap information and collecting log information.
Before configuring OSPF network optimization, you have configured:
IP addresses for interfaces
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OSPF basic functions
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You can configure the following timers on OSPF interfaces as needed:
Hello timer: Interval for sending hello packets, must be identical on OSPF
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neighbors. The longer the interval, the lower convergence speed and smaller
network load.
Poll timer: Interval for sending hello packets to the neighbor that is down on
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the NBMA network.
Dead timer: Interval within which if the interface receives no hello packet from
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the neighbor, it declares the neighbor is down.
Use the command...
default { cost cost | limit limit | tag
tag | type type } *
Remarks
Optional
By default, the default
cost is 1, default
upper limit of routes
redistributed per time
is 1000, default tag is
1 and default type of
redistributed routes is
type2.