HP 6125G HP 6125G & 6125G/XG Blade Switches Layer 3 - IP Routing Confi - Page 149

Enabling BGP and IGP route synchronization, Limiting prefixes received from a peer or peer group

Page 149 highlights

Step 3. Configure BGP route reception filtering policies. Command Remarks • Filter incoming routes with an ACL or IP prefix list: filter-policy { acl-number | ip-prefix ip-prefix-name } import • Reference a routing policy to filter routes from a peer or peer group: peer { group-name | ip-address } route-policy route-policy-name import Configure at least one command. No route reception filtering is configured by default. • Reference an ACL to filter routing information from a peer or peer group: If several filtering policies are configured, they are applied in the following sequence: peer { group-name | ip-address } 4. filter-policy import filter-policy acl-number import 5. peer filter-policy import • Reference an AS path list to filter routing information from a peer or peer group: peer { group-name | ip-address } as-path-acl as-path-acl-number import 6. peer as-path-acl import 7. peer ip-prefix import 8. peer route-policy import Only routes passing all the configured policies can be received. • Reference an IP prefix list to filter routing information from a peer or peer group: peer { group-name | ip-address } ip-prefix ip-prefix-name import Enabling BGP and IGP route synchronization By default, upon receiving an IBGP route, a BGP router checks the route's next hop. If the next hop is reachable, the BGP router advertises the route to EBGP peers. If the synchronization feature is configured, in addition to the reachability check of the next hop, the BGP router must find an active IGP route with the same destination network segment before it can advertise the IBGP route (use the display ip routing-table protocol command to check the IGP route state). To enable BGP and IGP synchronization: Step 1. Enter system view. 2. Enter BGP view. 3. Enable synchronization between BGP and IGP. Command system-view bgp as-number synchronization Remarks N/A N/A Not enabled by default. Limiting prefixes received from a peer or peer group Step 1. Enter system view. 2. Enter BGP view. Command system-view bgp as-number Remarks N/A N/A 139

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139
Step
Command
Remarks
3.
Configure BGP route
reception filtering
policies.
Filter incoming routes with an ACL or
IP prefix list:
filter-policy
{
acl-number
|
ip-prefix
ip-prefix-name
}
import
Reference a routing policy to filter
routes from a peer or peer group:
peer
{
group-name
|
ip-address
}
route-policy
route-policy-name
import
Reference an ACL to filter routing
information from a peer or peer
group:
peer
{
group-name
|
ip-address
}
filter-policy
acl-number
import
Reference
an AS path list to filter
routing information from a peer or
peer group:
peer
{
group-name
|
ip-address
}
as-path-acl
as-path-acl-number
import
Reference an IP prefix list to filter
routing information from a peer or
peer group:
peer
{
group-name
|
ip-address
}
ip-prefix
ip-prefix-name
import
Configure at least one command.
No route reception filtering is
configured by default.
If several filtering policies are
configured, they are applied in the
following sequence:
4.
filter-policy import
5.
peer filter-policy import
6.
peer as-path-acl import
7.
peer ip-prefix import
8.
peer route-policy import
Only routes passing all the
configured policies can be received.
Enabling BGP and IGP route synchronization
By default, upon receiving an IBGP route, a BGP router checks the route’s next hop. If the next hop is
reachable, the BGP router advertises the route to EBGP peers. If the synchronization feature is configured,
in addition to the reachability check of the next hop, the BGP router must find an active IGP route with the
same destination network segment before it can advertise the IBGP route (use the
display ip routing-table
protocol
command to check the IGP route state).
To enable BGP and IGP synchronization:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter BGP view.
bgp
as-number
N/A
3.
Enable synchronization
between BGP and IGP.
synchronization
Not enabled by default.
Limiting prefixes received from a peer or peer group
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter BGP view.
bgp
as-number
N/A