Chapter 16 - BGP | 273 |
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Special Communities
1.noexport - specifies that this route will not be advertised outside a BGP confederation boundary. A BGP confederation is a collec- tion of several AS’s that are advertised as a single AS to all BGP peers which are not members of the confederation.
2.noadv - specifies that this route will not be advertised to any BGP peers (including external peers).
3.noexpsub - specifies that this route will not be advertised to exter- nal peers. This means that this route can be advertised to internal peers only and will not be advertised outside its AS.
•addcomm (community number)
This modifier allows a community list to be prepended on the outgoing route. The parameters can be up to 6 community numbers and are speci- fied as integers.
Options/Input Modifiers
•ipaddr(IP address/optional bits) hasas(AS number) srcas(AS number) nhop(IP address) comm(community number)
This modifier (with the exception of hasas), limits input rules to routes originating from the designated IP address, AS number, next hop, or community. A BGP route contains information concerning each AS it has traversed. The hasas parameter specifies that the rule will be applied if the AS path contains the specified AS number anywhere in the AS path.
The IP address may be specified in any of the ways described previously. The AS number and community number are both specified as an integer.
•setpref (preference)
This modifier allows the preference to be set on incoming routes from the given IP address, AS number, community, or next hop. The preference is specified as an integer.
•setwt (weight)
This modifier allows the weight to be set on incoming routes from the given IP address, AS number, community, or next hop. The weight is specified as an integer.
