Benefits and Drawbacks of AToM-Based L2VPNs
Knowing that AToM pseudowires do a similar job to L2TPv3 pseudowires, you will not be surprised to learn that AToM-based L2VPNs share many advantages and disadvantages with L2TPv3-based L2VPNs.
Some of the main advantages for service providers implementing AToM-based L2VPNs are as follows:
- AToM-based L2VPNs are MPLS based, and are therefore deployed over an MPLS backbone network. It is possible to implement AToM over a Generic Routing Encapsulation (GRE) tunnel (and an IP backbone), but this is not a typical method of implementation.
- AToM allows the consolidation of service provider legacy and MPLS backbone networks. This consolidation of legacy and MPLS networks allows the service provider to save on operational and capital expenditure, while maintaining revenues for both legacy and IP/MPLS services.
- Service providers can use AToM to deploy both legacy Layer 2 (Frame Relay and so on) and newer Ethernet service offerings.
- Because AToM is MPLS based, a service provider can provision high service availability and traffic protection for AToM-based L2VPNs using MPLS traffic engineering (MPLS-TE) and MPLS-TE fast-reroute.
Some of the main advantages of AToM-based L2VPNs for enterprises are as follows:
- AToM-based L2VPNs can be used to transport non-IP protocols such as Internetwork Packet Exchange (IPX) between enterprise sites.
- Enterprises can maintain complete control of their routing when using AToM-based L2VPNsProvider Edge (PE) routers do not participate in enterprise routing (unlike with MPLS Layer 3 VPNs).
- MPLS-based pseudowires can be used to provision both Virtual Private Wire Service (VPWS) and Virtual Private LAN Service (VPLS) architectures. Note, however, that although Label Distribution Protocol (LDP)-signaled MPLS pseudowires are used in both VPWS and VPLS architectures, the AToM command syntax described in this chapter is used for VPWS. For more information on VPLS, see Appendix A, "VPLS and IPLS Layer 2 VPNs."
Now that you understand the motivations behind the deployment of AToM-based L2VPNs, it is time to move on to a discussion of their underlying operation.
Part I: Understanding VPN Technology
What Is a Virtual Private Network?
- What Is a Virtual Private Network?
- VPN Devices
- Deploying Site-to-Site and Remote Access VPNs: A Comparison
- Summary
- Review Questions
Part II: Site-to-Site VPNs
Designing and Deploying L2TPv3-Based Layer 2 VPNs
- Designing and Deploying L2TPv3-Based Layer 2 VPNs
- Benefits and Drawbacks of L2TPv3-Based L2VPNs
- L2TPv3 Pseudowire Operation
- Configuring and Verifying L2TPv3 Pseudowires
- Summary
- Review Questions
Designing and Implementing AToM-Based Layer 2 VPNs
- Designing and Implementing AToM-Based Layer 2 VPNs
- Benefits and Drawbacks of AToM-Based L2VPNs
- AToM Pseudowire Operation
- Deploying AToM Pseudowires
- Implementing Advanced AToM Features
- Summary
- Review Questions
Designing MPLS Layer 3 Site-to-Site VPNs
- Designing MPLS Layer 3 Site-to-Site VPNs
- Advantages and Disadvantages of MPLS Layer 3 VPNs
- MPLS Layer 3 VPNs Overview
- A Detailed Examination of MPLS Layer 3 VPNs
- Deploying MPLS Layer 3 VPNs
- Summary
- Review Questions
Advanced MPLS Layer 3 VPN Deployment Considerations
- Advanced MPLS Layer 3 VPN Deployment Considerations
- The Carriers Carrier Architecture
- The Inter-Autonomous System/Interprovider MPLS VPN Architecture
- Supporting Multicast Transport in MPLS Layer 3 VPNs
- Implementing QoS for MPLS Layer 3 VPNs
- Supporting IPv6 Traffic Transport in MPLS Layer 3 VPNs Using 6VPE
- Summary
- Review Questions
Deploying Site-to-Site IPsec VPNs
- Deploying Site-to-Site IPsec VPNs
- Advantages and Disadvantages of IPsec Site-to-Site VPNs
- IPsec: A Security Architecture for IP
- Deploying IPsec VPNs: Fundamental Considerations
- Summary
- Review Questions
Scaling and Optimizing IPsec VPNs
- Scaling and Optimizing IPsec VPNs
- Scaling IPsec Virtual Private Networks
- Ensuring High Availability in an IPsec VPN
- Designing QoS for IPsec VPNs
- MTU and Fragmentation Considerations in an IPsec VPN
- Summary
- Review Questions
Part III: Remote Access VPNs
Designing and Implementing L2TPv2 and L2TPv3 Remote Access VPNs
- Designing and Implementing L2TPv2 and L2TPv3 Remote Access VPNs
- Benefits and Drawbacks of L2TP Remote Access VPNs
- Operation of L2TP Voluntary/Client-Initiated Tunnel Mode
- Implementing L2TP Voluntary/Client-Initiated Tunnel Mode Remote Access VPNs
- Designing and Implementing L2TP Compulsory/NAS-Initiated Tunnel Mode Remote Access VPNs
- Integrating L2TP Remote Access VPNs with MPLS VPNs
- Summary
- Review Questions
Designing and Deploying IPsec Remote Access and Teleworker VPNs
- Designing and Deploying IPsec Remote Access and Teleworker VPNs
- Comparing IPsec Remote Access VPNs with Other Types of Remote Access VPNs
- Understanding IKE in an IPsec Remote Access VPN Environment
- Deploying IPsec Remote Access VPNs Using Preshared Key and Digital Signature Authentication
- Summary
- Review Questions
Designing and Building SSL Remote Access VPNs (WebVPN)
- Designing and Building SSL Remote Access VPNs (WebVPN)
- Comparing SSL VPNs to Other Types of Remote Access VPNs
- Understanding the Operation of SSL Remote Access VPNs
- Using Clientless SSL Remote Access VPNs (WebVPN) on the Cisco VPN 3000 Concentrator
- Implementing Full Network Access Using the Cisco SSL VPN Client
- Strengthening SSL Remote Access VPNs Security by Implementing Cisco Secure Desktop
- Enabling SSL VPNs (WebVPN) on Cisco IOS Devices
- Deploying SSL VPNs (WebVPN) on the ASA 5500
- Summary
- Review Questions
Part IV: Appendixes
Designing and Building SSL Remote Access VPNs (WebVPN)
- Designing and Building SSL Remote Access VPNs (WebVPN)
- Appendix A. VPLS and IPLS Layer 2 VPNs
- Understanding VPLS
- Understanding IPLS
- Summary: Comparing VPLS and IPLS
Appendix B. Answers to Review Questions
EAN: 2147483647
Pages: 124
