268
Configuring EBGP between a PE and a CE
1.
Configure the PE:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enable BGP and enter BGP
view.
bgp
as-number
N/A
3.
Enter BGP VPN instance
view.
ipv4-family vpn-instance
vpn-instance-name
N/A
4.
Configure the CE as the
VPN EBGP peer.
peer
{
group-name
|
ip-address
}
as-number
as-number
N/A
5.
Redistribute the routes of the
local CEs.
import-route
protocol
[
process-id
] [
med
med-value
|
route-policy
route-policy-name
]
*
A PE must redistribute the routes
of the local CEs into its VPN
routing table so it can advertise
them to the peer PE.
6.
Configure BGP to filter
routes to be advertised.
filter-policy
{
acl-number
|
ip-prefix
ip-prefix-name
}
export
[
direct
|
isis
process-id
|
ospf
process-id
|
rip
process-id
|
static
]
Optional.
By default, BGP does not filter
routes to be advertised.
7.
Configure BGP to filter
received routes.
filter-policy
{
acl-number
|
ip-prefix
ip-prefix-name
}
import
Optional.
By default, BGP does not filter
received routes.
8.
Allow the local AS number to
appear in the AS_PATH
attribute of a received route
and set the maximum
number of repetitions.
peer
{
group-name
|
ip-address
}
allow-as-loop
[
number
]
Optional.
Required for a hub-spoke
network.
BGP detects routing loops by AS
number. In a hub-spoke network
where EBGP is running between
a PE and a CE, the routing
information the PE advertises to a
CE carries the number of the AS
where the PE resides. Therefore,
the route updates that the PE
receives from the CE also include
the number of the AS where the
PE resides. This causes the PE
unable to receive the route
updates. In this case, you must
configure this command to allow
routing loops.
2.
Configure the CE:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter BGP view.
bgp
as-number
N/A
3.
Configure the PE as the
EBGP peer.
peer
{
group-name
|
ip-address
}
as-number
as-number
For more information about BGP
peer and peer group
configuration, see
Layer 3—IP
Routing Configuration Guide
. This
chapter does not differentiate
between peer and peer group.