R0106-HP MSR Router Series Layer 3 - IP Routing Configuration Guide(V7)

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Configuring the AS_PATH attribute
Permitting local AS number to appear in routes from a peer or peer group
In general, BGP checks whether the AS_PATH attribute of a route from a peer contains the local AS
number. If yes, it discards the route to avoid routing loops.
In certain network environments (for example, a Hub&Spoke network in MPLS L3VPN), however, the
AS_PATH attribute of a route from a peer must be allowed to contain the local AS number. Otherwise, the
route cannot be advertised correctly.
To permit the local AS number to appear in routes from a peer or peer group and specify the
appearance times (IPv4 unicast/multicast address family):
Ste
p
Command Remarks
1. Enter system view.
system-view N/A
2. Enter BGP IPv4 unicast address
family view, BGP-VPN IPv4
unicast address family view, or
BGP IPv4 multicast address
family view.
• Enter BGP IPv4 unicast address
family view:
a. bgp as-number
b. address-family ipv4
[ unicast ]
• Enter BGP-VPN IPv4 unicast
address family view:
c. bgp as-number
d. ip vpn-instance
vpn-instance-name
e. address-family ipv4
[ unicast ]
• Enter BGP IPv4 multicast
address family view:
f. bgp as-number
g. address-family ipv4
multicast
N/A
3. Permit the local AS number to
appear in routes from a peer or
peer group and specify the
appearance times.
peer { group-name | ip-address }
allow-as-loop [ number ]
By default, the local AS number is
not allowed in routes from a peer
or peer group.
To permit the local AS number to appear in routes from a peer or peer group and specify the
appearance times (IPv6 unicast/multicast address family):
Ste
p
Command Remarks
1. Enter system view.
system-view N/A