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8-32 neighbor { ip-address peer- group - name } unsuppress-map route-map-nameSyntax Description:
Purpose: When the aggregate-address command is used with the summary-only option, the more-specific routes of the aggregate are suppressed (see section 1-7). The aggregate-address summary-only command suppresses the more-specific routes to all neighbors. You can use an unsuppress map to selectively leak more-specific routes to a particular neighbor. Cisco IOS Software Release: 10.0. Peer group support was added in Release 11.0. Configuration Example: Selectively Advertising Routes with an Unsuppress MapIn Figure 8-31, Router A is advertising four prefixes to Router B. Router B aggregates these prefixes and advertises only the summary while suppressing the four specific routes. This will be used as the initial configuration so that we can inspect the BGP tables for Routers B and C. The unsuppress map is then added to Router B's configuration. Figure 8-31. Globally Suppressed Routes Can Be Selectively Unsuppressed on a Per-Neighbor Basis
Router A interface Loopback0 ip address 172.16.0.1 255.255.255.0 ! interface Loopback1 ip address 172.16.1.1 255.255.255.0 ! interface Loopback2 ip address 172.16.2.1 255.255.255.0 ! interface Loopback3 ip address 172.16.3.1 255.255.255.0 ! router bgp 65530 network 172.16.0.0 mask 255.255.255.0 network 172.16.1.0 mask 255.255.255.0 network 172.16.2.0 mask 255.255.255.0 network 172.16.3.0 mask 255.255.255.0 neighbor 10.1.1.2 remote-as 1 __________________________________________________________________________ Router B router bgp 1 aggregate-address 172.16.0.0 255.255.0.0 summary-only neighbor 10.1.1.1 remote-as 65530 neighbor 10.1.2.2 remote-as 2 __________________________________________________________________________ Router C router bgp 2 neighbor 10.1.2.1 remote-as 1 Before proceeding to the unsuppress map, check the BGP tables on Routers B and C: rtrB# show ip bgp BGP table version is 42, local router ID is 172.16.1.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path s> 172.16.0.0/24 10.1.1.1 0 0 65530 i *> 172.16.0.0 0.0.0.0 32768 i s> 172.16.1.0/24 10.1.1.1 0 0 65530 i s> 172.16.2.0/24 10.1.1.1 0 0 65530 i s> 172.16.3.0/24 10.1.1.1 0 0 65530 i __________________________________________________________________________ rtrC# show ip bgp BGP table version is 10, local router ID is 156.26.32.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path *> 172.16.0.0 10.1.2.1 0 1 i As you can see, Router B is suppressing the more-specific routes. Next, we want to unsuppress prefix 172.16.2.0 on Router B and allow this route to be advertised to Router C: Router B router bgp 1 aggregate-address 172.16.0.0 255.255.0.0 summary-only neighbor 10.1.1.1 remote-as 65530 neighbor 10.1.2.2 remote-as 2 neighbor 10.1.2.2 unsuppress-map allow ! access-list 1 permit 172.16.2.0 0.0.0.255 route-map allow permit 10 match ip address 1 VerificationThere should be no change to Router B's BGP table: rtrB# sh ip bgp BGP table version is 10, local router ID is 172.16.1.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path s> 172.16.0.0/24 10.1.1.1 0 0 65530 i *> 172.16.0.0 0.0.0.0 32768 i s> 172.16.1.0/24 10.1.1.1 0 0 65530 i s> 172.16.2.0/24 10.1.1.1 0 0 65530 i s> 172.16.3.0/24 10.1.1.1 0 0 65530 i However, Router C should not be receiving the unsuppressed route: RtrC# sh ip bgp BGP table version is 14, local router ID is 156.26.32.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path *> 172.16.0.0 10.1.2.1 0 1 i *> 172.16.2.0/24 10.1.2.1 0 1 65530 i Troubleshooting
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