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BigIron RX Series Configuration Guide
53-1002253-01
Redistributing IBGP routes
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You can enable the device to always compare the MEDs, regardless of the AS information in the
paths. For example, if the router receives UPDATES for the same route from neighbors in three ASs,
the router would compare the MEDs of all the paths together, rather than comparing the MEDs for
the paths in each AS individually.
NOTE
By default, value 0 (most favorable) is used in MED comparison when the MED attribute is not
present. The default MED comparison results in the device favoring the route paths that are missing
their MEDs. You can use the med-missing-as-worst command to make the device regard a BGP route
with a missing MED attribute as the least favorable route, when comparing the MEDs of the routes.
NOTE
MED comparison is not performed for internal routes originated within the local AS or confederation
unless the compare-med-empty-aspath command is configured.
NOTE
The AS-path is empty when routes are redistributed from other protocols (e.g. redistribute static,
redistribute connected, or redistribute OSPF).
To configure the router to always compare MEDs, enter the following command.
BigIron RX(config-bgp)# always-compare-med
Syntax: [no] always-compare-med
The following BGP command directs BGP to take the MED value into consideration even if the route
has an empty as-path path attribute.
BigIron RX(config) router bgp
BigIron RX(config-bgp-router)# compare-med-empty-aspath
Syntax: [no] compare-med-empty-aspath
Disabling or re-enabling comparison of the AS-path length
AS-Path comparison is Step 5 in the algorithm BGP4 uses to select the next path for a route.
Comparison of the AS-Path length is enabled by default. To disable it, enter the following command
at the BGP configuration level of the CLI.
BigIron RX(config-bgp)# as-path-ignore
This command disables comparison of the AS-Path lengths of otherwise equal paths. When you
disable AS-Path length comparison, the BGP4 algorithm shown in “How BGP4 Selects a Path for a
Route” on page 26-3 skips from Step 4 to Step 6.
Syntax: [no] as-path-ignore
Redistributing IBGP routes
By default, the device does not redistribute IBGP routes from BGP4 into RIP, OSPF, or ISIS. This
behavior helps eliminate routing loops. However, if your network can benefit from redistributing the
IBGP routes from BGP4 into OSPF, ISIS or RIP, you can enable the device to redistribute the routes.
To enable the device to redistribute BGP4 routes into OSPF, RIP, or ISIS, enter the following
command.
Содержание BigIron RX Series
Страница 100: ...24 BigIron RX Series Configuration Guide 53 1002253 01 Logging on through the Web Management Interface 2 ...
Страница 192: ...116 BigIron RX Series Configuration Guide 53 1002253 01 Configuring authentication method lists 4 ...
Страница 228: ...152 BigIron RX Series Configuration Guide 53 1002253 01 Enabling WAN PHY mode support 6 ...
Страница 312: ...236 BigIron RX Series Configuration Guide 53 1002253 01 Displaying IP information 7 ...
Страница 356: ...280 BigIron RX Series Configuration Guide 53 1002253 01 Resetting LLDP statistics 9 ...
Страница 402: ...326 BigIron RX Series Configuration Guide 53 1002253 01 Transparent firewall mode 11 ...
Страница 432: ...356 BigIron RX Series Configuration Guide 53 1002253 01 SuperSpan 12 ...
Страница 500: ...424 BigIron RX Series Configuration Guide 53 1002253 01 MRP CLI example 14 ...
Страница 580: ...504 BigIron RX Series Configuration Guide 53 1002253 01 Configuring multicast traffic engineering 18 ...
Страница 591: ...BigIron RX Series Configuration Guide 515 53 1002253 01 Displaying traffic reduction 19 ...
Страница 592: ...516 BigIron RX Series Configuration Guide 53 1002253 01 Displaying traffic reduction 19 ...
Страница 598: ...522 BigIron RX Series Configuration Guide 53 1002253 01 Viewing Layer 2 ACLs 20 ...
Страница 656: ...580 BigIron RX Series Configuration Guide 53 1002253 01 Trunk formation 22 ...
Страница 754: ...678 BigIron RX Series Configuration Guide 53 1002253 01 Displaying RIP filters 24 ...
Страница 814: ...738 BigIron RX Series Configuration Guide 53 1002253 01 Displaying OSPF information 25 ...
Страница 932: ...856 BigIron RX Series Configuration Guide 53 1002253 01 Generalized TTL security mechanism support 26 ...
Страница 980: ...904 BigIron RX Series Configuration Guide 53 1002253 01 Clearing IS IS information 28 ...
Страница 1000: ...924 BigIron RX Series Configuration Guide 53 1002253 01 Using secure copy 30 ...
Страница 1088: ...1012 BigIron RX Series Configuration Guide 53 1002253 01 IP source guard 35 ...
Страница 1108: ...1032 BigIron RX Series Configuration Guide 53 1002253 01 Reading CDP packets 37 ...
Страница 1126: ...1050 BigIron RX Series Configuration Guide 53 1002253 01 Clearing sFlow statistics 39 ...
Страница 1140: ...1064 BigIron RX Series Configuration Guide 53 1002253 01 802 1s Multiple Spanning Tree Protocol 40 ...
Страница 1324: ...1248 BigIron RX Series Configuration Guide 53 1002253 01 Displaying OSPFv3 information 48 ...
Страница 1363: ...BigIron RX Series Configuration Guide 1287 53 1002253 01 Continuous System Monitor 51 ...
Страница 1364: ...1288 BigIron RX Series Configuration Guide 53 1002253 01 Continuous System Monitor 51 ...
Страница 1404: ...1328 BigIron RX Series Configuration Guide 53 1002253 01 Commands That Require a Reload D ...
Страница 1458: ...1382 BigIron RX Series Configuration Guide 53 1002253 01 VSRP E ...