Figure 5-6 Asymmetrically Connected Ces - Huawei Quidway S9300 Configuration Manual

Quidway S9300 Terabit Routing Switch
Configuration Guide - VPN
PW FRR
With the wide applications of PWE3, the requirement for the reliability of networks becomes
increasingly higher, especially for L2VPNs that carry real-time services such as VoIP or IPTV.
PW fast reroute (PW FRR) is one of the solutions to increasing the reliability of L2VPNs.
The PW FRR supported by the S9300 is used in the following networking:
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Inter-AS PWE3
In actual networking, multiple sites of the 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 the following schemes:
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The S9300 supports Inter-AS PWE3-Option A solutions. The following is the description:
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Issue 03 (2009-08-20)
Dynamic-and-static switch: One of the PWs is set up with signaling, and the other one
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is set up manually.
The preceding types of PW switching support the Control Word (CW) and Virtual Circuit
Connectivity Verification (VCCV). The CW and VCCV are sent from two U-PEs to the
S-PE through labels.
NOTE
S9300 does not support the dual-homed CE.
Asymmetrically connected CE devices: One CE is connected to a PE through an AC and
the other CE is dual-homed to PEs through two ACs, as shown in

Figure 5-6 Asymmetrically connected CEs

PE1
CE1
Site1
Inter-AS PWE3-Option A: Data of an inter-AS user is transmitted through dedicated
interfaces between ASBRs. The user exclusively occupies the link between the ASBRs.
Inter-AS PWE3-Option B: The dynamic PW switching is performed between ASBRs.
Inter-AS PWE3-Option C: The PEs advertise the VPNv4 routes through multi-hop MP-
EBGP.
Inter-AS PWE3-OptionA
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PE2
P1
VPN backbone
P2
PE3
5 PWE3 Configuration
Figure 5-6.
CE2
AC1
Site2
5-7