Controlling Granularity Of Routing Information; Configuring A Global Default Metric - Juniper IGP - CONFIGURATION GUIDE V11.1.X Configuration Manual

JUNOSe 11.0.x IP, IPv6, and IGP Configuration Guide

Controlling Granularity of Routing Information

You can force the distribution of level 2 routing information to level 1 routers in other
areas to improve the quality of the resulting routes, but at the cost of reduced
scalability.
distribute-domain-wide

Configuring a Global Default Metric

You can use the metric command to specify a global default metric that applies to
all active IS-IS interfaces. This command enables you to avoid configuring the desired
metric on each active interface individually when you want all IS-IS interfaces to have
the same metric, but a different value than the individual default of 10. The global
default metric applies to both level 1 and level 2 interfaces unless you restrict it to
one level.
If you have configured a nondefault metric on any IS-IS interface with the isis metric
command, that value overrides the global default metric.
Reference bandwidth takes precedence over both individual and global default
metrics. If you have configured a reference bandwidth, the metric command has no
effect on interface metrics,
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Configuring Global IS-IS Parameters
Use the no version to stop redistribution of IP routes between the specified levels.
See redistribute isis ip
Use to increase the granularity of routing information within a domain.
Domainwide prefix distribution enables a routing domain running with both
level 1 and level 2 IS-IS routers to distribute IP prefixes from level 2 to level 1
between areas.
The major advantage for using domainwide prefix distribution is to improve the
quality of the resulting routes within a domain by distributing more specific
information.
The major disadvantage of using domainwide prefix distribution is that it affects
the scalability of IS-IS. When used, it increases the number of prefixes throughout
the domain, causing increased memory consumption, transmission requirements,
and computation requirements throughout the domain.
A trade-off decision must be made between scalability and optimality.
Issue this command from within the IS-IS IPv6 address family to increase the
granularity of IPv6 routing information within a domain.
Example
host1(config-router)#distribute-domain-wide
Use the no version to halt the distribution of routes from level 2 to level 1.
See distribute-domain-wide