H3C Technologies H3C S10500 Series Switches - Manual (Page 27)

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NOTE:
On a PE or the egress router of a site, you must configure the MCE as the iBGP peer. If the routing protocol
of the site is not iBGP, redistribute the routes of the routing protocol to iBGP. The configuration required is
the same as that of common iBGP. For more information about iBGP, see Layer 3—IP Routing
Configuration Guide.
Configuring eBGP
If eBGP is used for exchanging routing information between an MCE and a PE, you must configure the
MCE and the PE as the peer of each other in BGP-VPN instance view at both sides, redistribute the VPN
routes of the VPN sites to the MCE, and then advertise the VPN routes to the PE.
If eBGP is used for exchanging routing information between a MCE and a VPN site, you must configure
a BGP peer for each VPN instance, respectively and redistribute the IGP routes of each VPN instance into
the routing table of the corresponding BGP peer on the CE. As different sites are normally located in
different ASs, eBGP is used for route advertisement.
1. Redistribute IGP routes of each VPN site to eBGP
To advertise VPN routes to the PE correctly, the MCE must redistribute the IGP routes of each directly
connected VPN site to the BGP routing table of the MCE.
2. Configure a peer group for each VPN instance
For the MCE to exchange routing information with each site correctly, you must configure a peer group
for each VPN instance and specify an AS number for each peer group in BGP-VPN instance view.
3. Filter routes by using filter policies
For the MCE to send the routing information to the sites and PE correctly, you must configure a filter policy
to filter the received or sent routes.
Follow these steps to configure route exchange through eBGP:
To do… Use the command… Remarks
Enter system view system-view —
Enter BGP view bgp as-number —
Enter BGP-VPN instance view
ipv4-family vpn-instance
vpn-instance-name
Required
Add the VPN instance to a peer
group
peer { group-name | ip-address }
[ as-number as-number ]
Allow routing loops—Allow the
local AS number to appear in the
AS_PATH attribute of a received
route and set the maximum number
of times that such case is allowed
to appear.
peer { group-name | ip-address }
allow-as-loop [ number ]
Required
Use either command