Bgp Messages; Bgp Configuration Concerns - HP 7102dl - ProCurve Secure Router Configuration Manual

BGP Messages

BGP sends relatively few messages compared to a routing protocol such as
OSPF. A BGP update can include one new route and several withdrawn routes.
AS Field. When a BGP interface advertises a route, it adds its AS to the BGP
packet. The route thus accumulates a list of autonomous systems through
which packets must travel. The AS field is important because the organiza-
tions that own various autonomous systems have set arrangements with each
other about which networks they allow each other to access. Routers can
select routes according to the autonomous systems through which packets
must pass.
For basic BGP configuration on the ProCurve Secure Router, you need know
only that your ISP will provide you with its AS (the remote AS) and the AS
number for your local site.

BGP Configuration Concerns

To configure BGP on the ProCurve Secure Router, you must:
enable BGP and specify the local AS
advertise local networks
set the router ID
configure at least one BGP neighbor:
• set the BGP neighbor ID (IP address)
• specify the remote AS number
You can also:
configure policies for exchanging routes with a neighbor:
• define the routes that the router can advertise to or receive from a
neighbor, according to address, prefix length, or other attributes—
applications include:
– preventing multihomed routers from advertising external routes
– accepting routes only from authorized remote sites
– setting the policy for a community
• place a route in a community to request that the neighbor advertises
it to certain peers only
• apply attributes to accepted routes:
– local preference
– community
– deleting communities defined for the routes
IP Routing—Configuring RIP, OSPF, BGP, and PBR
Configuring BGP
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