What is one limitation of MPLS Layer 3 VPN networks?

The correct answer is C. They support only IP traffic. MPLS Layer 3 VPNs are designed exclusively around IP routing-PE routers exchange VPNv4 routes via MP-BGP and forward traffic using IP lookups with MPLS labels. They cannot natively transport non-IP legacy protocols (such as IPX or SNA), which is a key limitation (C). Choice A…

Advanced WAN Services

Question

Options

AThey require less powerful routers with limited capabilities
BThey require the customer to control routing
CThey support only IP traffic
DPE routers are underutilized

How the community answered

(44 responses)

A
5% (2)
B
7% (3)
C
86% (38)
D
2% (1)

Explanation

MPLS Layer 3 VPNs are designed exclusively around IP routing-PE routers exchange VPNv4 routes via MP-BGP and forward traffic using IP lookups with MPLS labels. They cannot natively transport non-IP legacy protocols (such as IPX or SNA), which is a key limitation (C). Choice A is incorrect because MPLS L3 VPN actually demands more powerful routers (PE routers must handle label imposition, VRF routing tables, and MP-BGP). Choice B is wrong because in MPLS L3 VPN, the service provider's PE routers manage routing transparently-the customer does not need to control it. Choice D is incorrect because PE routers in MPLS environments are heavily utilized, maintaining per-VRF routing tables and handling label operations.

Topics

#MPLS#L3 VPN#IP traffic limitation#service provider

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