Huawei quidway s7700 Configuration Manual page 562

Quidway S7700 Smart Routing Switch
Configuration Guide - VPN
Figure 6-7 Asymmetrically connected CEs
Inter-AS PWE3
In actual network, multiple sites of a VPN of a user may connect with multiple service providers
of different ASs or with multiple ASs of a service provider. The VPN is called inter-AS VPN.
Inter-AS PWE3 has two schemes:
l
l
The S7700 supports the Inter-AS PWE3-Option A
In Option A, the ASBRs of the two ASs are directly connected. The ASBRs are the PEs of their
respective ASs. The two ASBRs consider the peer ASBRs as their CE devices.
Figure 6-8 Networking diagram of inter-AS PWE3-Option A
Issue 01 (2011-07-15)
PE1
CE1
AC1
Site1
Inter-AS PWE3-Option A: Data of an inter-AS user is transmitted through special interfaces
between ASBRs. The user exclusively uses the link between the ASBRs.
Inter-AS PWE3-Option C: The PEs advertise the VPN IPv4 routes through multi-hop MP-
EBGP.
CE-1
PE-1
PE-2
LSP1
CE-2
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PE2
P1
VPN
backbone
P2
PE3
ASBR2
ASBR1
AC
6 PWE3 Configuration
AC2
CE2
AC3
Site2
PE-3
PE-4
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