3Com MSR 50 Series, Руководство по настройке

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1496 C
HAPTER
79: MPLS L3VPN C
ONFIGURATION
With the peer default-route-advertise vpn-instance command configured, the
SPE always advertises a default route using the local address as the next hop
address to the UPE, regardless of whether the default route is present in the local
routing table or not.
n
■
The default routes of a VPN instance can be advertised to only a BGP peer or
peer group that is UPE.
■
It is not recommended for an SPE to be connected to a CE directly. If an SPE
must be directly connected with a CE, the VPN instance on the SPE and that on
the UPE must be configured with different RDs.
Configuring OSPF
Sham Link
The sham link is considered an OSPF intra-area route. It is used to ensure that the
VPN traffic is transmitted over the backbone instead of the backdoor link between
two CEs.
The source and destination addresses of the sham link must be loopback interface
addresses with 32-bit masks. Besides, the loopback interfaces must be bound to
the VPN instances and be advertised through BGP.
Configuration
Prerequisites
Before configuring OSPF sham link, be sure to complete these tasks:
■
Configuring basic MPLS L3VPN (OSPF is used between PE and CE)
■
Configuring OSPF in the LAN where CEs reside
Configuring a Loopback
Interface
Follow these steps to configure a loopback interface:
To do... Use the command... Remarks
Enter system view system-view -
Enter BGP view bgp as-number -
Enter BGP-VPNv4 subaddress
family view ipv4-family vpnv4 Required
Enable the exchange of
BGP-VPNv4 routing
information with a peer peer { group-name |
ip-address } enable
Required
Specify a BGP peer or peer
group as the UPE peer { group-name |
ip-address } upe
Required
Specify to advertise default
routes of a VPN instance to a
UPE peer { group-name |
ip-address }
default-route-advertise
vpn-instance
vpn-instance-name
Optional
By default, BGP does not
advertise default routes to a
VPNv4 peer.
To do... Use the command... Remarks
Enter system view system-view -
Create a loopback interface
and enter loopback interface
view interface loopback
interface-number
Required
Bind the loopback interface to
VPN instance ip binding vpn-instance
vpn-instance-name
Required
By default, an interface is
associated with no VPN
instance.