Juniper JUNOSE, Configuration Manual

Page: 86 / 738

If instead you initially configure the router as passive for those peers, BGP will not
attempt to establish sessions to those peers but will wait until these remote peers
initiate a session, thus conserving CPU resources.
If you configure both sides of a BGP session as passive, then the session can never
come up because neither side can initiate the connection.
neighbor passive
■
Use to configure the BGP speaker to only accept inbound BGP connections from
the specified peer and never initiate outbound connections to that peer.
■
This command takes effect immediately. If the session is not yet established,
BGP immediately stops initiating outbound connections to the peer. If the session
is already established, it is not bounced regardless of which side initiated the
connection.
■
If you specify a BGP peer group by using the peerGroupName argument, all the
members of the peer group inherit the characteristic configured with this
command unless it is overridden for a specific peer.
■
Example
host1(config-router)# neighbor 10.12.3.5 passive
■
Use the no version to restore the default condition, permitting the initiation of
outbound connections to the peer.
■
See neighbor passive.
Advertising Routes
Each BGP speaker advertises to its peers the routes to prefixes that it can reach.
These routes include:
■
Routes to prefixes originating within the speaker’s AS
■
Routes redistributed from another protocol, including static routes
By default, BGP does not advertise any route unless the router’s IP routing table also
contains the route.
Prefixes Originating in an AS
Use the network command to configure a router with the prefixes that originate
within its AS. Thereafter the router advertises these configured prefixes with the
origin attribute set to IGP. See “Understanding the Origin Attribute” on page 117 for
more information about origins. Figure 13 on page 51 shows a network structure of
three autonomous systems, each with a router that originates certain prefixes.
50 ■
Advertising Routes
JUNOSe 11.0.x BGP and MPLS Configuration Guide