Configuring BGP4
December 2005
© Foundry Networks, Inc.
21 - 9
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Change the default local preference, default information originate setting, or administrative distance.
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Enable or disable use of a default route to resolve a BGP4 next-hop route.
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Enable or disable MED (metric) comparison.
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Require the first AS in an Update from an EBGP neighbor to be the neighbor’s AS.
•
Change MED comparison parameters.
•
Disable comparison of the AS-Path length.
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Enable comparison of the router ID.
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Enable next-hop recursion.
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Enable or disable auto summary.
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Change the default metric.
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Disable or re-enable route reflection.
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Configure confederation parameters.
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Disable or re-enable load sharing.
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Change the maximum number of load-sharing paths.
•
Change other load-sharing parameters.
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Define route flap dampening parameters.
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Add, change, or negate redistribution parameters (except changing the default MED; see below).
•
Add, change, or negate route maps (when used by the
network
command or a redistribution command).
After Resetting Neighbor Sessions
The following parameter changes take effect only after the router’s BGP4 sessions are cleared, or reset using the
“soft” clear option. (See “Closing or Resetting a Neighbor Session” on page 21-105.)
•
Change the Hold Time or Keep Alive Time.
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Aggregate routes.
•
Add, change, or negate filter tables.
After Disabling and Re-Enabling Redistribution
The following parameter change takes effect only after you disable and then re-enable redistribution:
•
Change the default MED (metric).
Memory Considerations
BGP4 handles a very large number of routes and therefore requires a lot of memory. For example, in a typical
configuration with just a single BGP4 neighbor, a BGP4 router may need to be able to hold up to 80,000 routes.
Many configurations, especially those involving more than one neighbor, can require the router to hold even more
routes. Foundry Layer 3 Switches and NetIron Internet Backbone routers provide dynamic memory allocation for
BGP4 data. These devices automatically allocate memory when needed to support BGP4 neighbors, routes, and
route attribute entries. Dynamic memory allocation is performed automatically by the software and does not
require a reload.
Содержание FastIron Edge Switch X424
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