H3C Technologies H3C S12500-X Series Switches - Manual (Page 105)

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Configuring tunnel policies
Overview
Tunnel policies enable a PE to forward traffic for each MPLS VPN over a preferred tunnel or over multiple
tunnels when the PE has multiple tunnels to the peer PE. The tunnels supported by MPLS VPN include
MPLS LSPs and MPLS TE tunnels.
For more information about MPLS TE, see "Configuring MPLS TE." For more information about MPLS
VPNs, see "Configuring MPLS L3VPN," "Configuring MPLS L2VPN," and "Configuring VPLS."
Configuring a tunnel policy
Configuration guidelines
• To select a preferred tunnel, create a tunnel policy and specify the preferred tunnel with the
preferred-path command. The destination address of the preferred tunnel identifies a peer PE so the
PE will forward traffic destined for that peer PE over the preferred tunnel. If you specify multiple
preferred tunnels that have the same destination address in a tunnel policy, only the first configured
tunnel takes effect. If the first tunnel is not available, the second tunnel is used, and so forth. No load
balancing will be performed on these tunnels. This method explicitly specifies an MPLS TE tunnel for
an MPLS VPN, facilitating traffic planning. H3C recommends that you use this method.
• To select multiple tunnels for load sharing, create a tunnel policy and specify the tunnel selection
order and the number of tunnels by using the select-seq load-balance-number command. A tunnel
type closer to the select-seq keyword has a higher priority. For example, the select-seq lsp cr-lsp
load-balance-number 3 command gives LSP higher priority. If no LSP is available or the number of
LSPs is less than 3, VPN uses CRLSP tunnels. The tunnels selected by this method are not fixed,
complicating traffic planning. H3C recommends not using this method.
If you configure both methods for a tunnel policy, the tunnel policy selects tunnels in the following steps:
1. If the destination address of a preferred tunnel identifies a peer PE, the tunnel policy uses the
preferred tunnel to forward traffic destined for the peer PE without using any other tunnels.
2. If not, the tunnel policy selects tunnels as configured by the select-seq load-balance-number
command.