Example 2
Consider the following commands used to configure router Chicago in Figure 24 on
page 89:
host1(config)#
router bgp 293
host1(config-router)#
neighbor 10.5.5.2 remote-as 32
host1(config-router)#
neighbor 10.5.5.2 filter-list 1 in
host1(config-router)#
neighbor 10.2.2.4 remote-as 17
host1(config-router)#
exit
host1(config)#
ip as-path access-list 1 deny ^32$
Figure 24: Assigning a Filter List
Access list 1 denies routes that originate in AS 32—and therefore routes originated
by router NY—because the AS-path attribute for these routes begins with (and indeed
consists only of) the value 32.
Routes originating anywhere else—such as in AS 837, AS 17, or AS 451—are
permitted, because their AS-path attributes do not begin with 32.
ip as-path access-list
■
Use to define an AS-path access list to permit or deny routes based on the AS
path.
■
Each access list is a set of permit or deny conditions for routes based on matching
a route’s AS path with a regular expression. If the regular expression matches
the representation of the AS path of the route as an ASCII string, then the permit
or deny condition applies. The AS path does not contain the local AS number.
■
Use the
neighbor filter-list
command to apply the AS-path access list. You can
apply access list filters to inbound and outbound BGP routes. You can assign
weights to routes matching the AS-path access list.
■
Use the
no
version to remove a single access list entry if permit or deny and a
path-expression are specified. Otherwise, the entire access list is removed.
■
See ip as-path access-list.
neighbor filter-list
Configuring BGP Routing Policy
■
89
Chapter 1: Configuring BGP Routing
Summary of Contents for BGP
Page 6: ...vi ...
Page 8: ...viii JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 37: ...Part 1 Border Gateway Protocol Configuring BGP Routing on page 3 Border Gateway Protocol 1 ...
Page 38: ...2 Border Gateway Protocol JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 234: ...198 Monitoring BGP JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 236: ...200 Multiprotocol Layer Switching JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 542: ...506 Monitoring BGP MPLS VPNs JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 544: ...508 Layer 2 Services Over MPLS JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 610: ...574 Virtual Private LAN Service JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 624: ...588 VPLS References JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 680: ...644 Virtual Private Wire Service JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 724: ...688 Monitoring MPLS Forwarding Table for VPWS JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 725: ...Part 6 Index Index on page 691 Index 689 ...
Page 726: ...690 Index JUNOSe 11 1 x BGP and MPLS Configuration Guide ...