3Com S7906E - Switch, Руководство по настройке

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Figure 1-18 Application of BGP AS number substitution
In Figure 1-18 , both CE 1 and CE 2 use the AS number of 800. AS number substitution is enabled on
PE 2 for CE 2. Before advertising updates received from CE 1 to CE 2, PE 2 finds that an AS number in
the AS_PATH is the same as that of CE 2 and hence substitutes its own AS number 100 for the AS
number. In this way, CE 2 can normally receive the routing information from CE 1.
AS number substitution also applies to a PE connecting multiple CEs through different interfaces, such
as PE 2 in Figure 1-18 , which connects CE 2 and CE 3.
For a multi-homed CE, that is, a CE connected with multiple PEs, the BGP AS number substitution
function must be used in combination with the site-of-origin (SOO) function. Otherwise, routing loops
may appear.
MPLS L3VPN Configuration Task List
Complete the following tasks to conf
Task Remarks
Configuring VPN Instances Required
Configuring Basic MPLS L3VPN Required
Configuring Inter-Provider VPN
Optional
Configure it as needed
Configuring Nested VPN
Optional
Configure it as needed
Configuring HoVPN
Optional
Configure it as needed
Configuring OSPF Sham Link
Optional
Configure it as needed