Three Drawbacks of VPLS - CCDE Exam 352-001 | Cisco

Drawbacks of VPLS

Question

What are three drawbacks of VPLS? (Choose three.)

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Explanations

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ACD.

VPLS (Virtual Private LAN Service) is a technology used to extend a Layer 2 Ethernet network over a wide area network (WAN). While VPLS provides many benefits, there are also several drawbacks.

The three drawbacks of VPLS are:

  1. Direct-attached VPLS requires a full mesh of pseudowires: VPLS uses a pseudowire (PW) to connect two or more sites. Direct-attached VPLS requires a full mesh of pseudowires, which means that each site must have a PW connection to every other site. As the number of sites increases, the number of PW connections required grows quickly, leading to increased complexity and cost.

  2. MAC scalability may be problematic: In VPLS, the customer MAC addresses are visible on the service provider network, which can lead to scalability issues. As the number of customer MAC addresses increases, the service provider must ensure that the MAC tables on all VPLS switches are synchronized to avoid MAC address table overflow.

  3. VPLS requires a large amount of multicast and broadcast replication: VPLS requires the service provider to replicate multicast and broadcast traffic to all VPLS sites. As the number of VPLS sites increases, the amount of multicast and broadcast traffic also increases, leading to increased network congestion and potential performance issues.

  4. VPLS cannot support IP bridging: VPLS is designed to extend Layer 2 Ethernet networks, and does not support IP bridging as defined in the VPLS standard. This means that VPLS cannot be used to extend IP subnets over a wide area network.

In summary, while VPLS provides many benefits, including the ability to extend Layer 2 Ethernet networks over a wide area network, it also has several drawbacks, including the need for a full mesh of pseudowires, MAC scalability issues, a large amount of multicast and broadcast replication, and the inability to support IP bridging.