Enterprise QoS Solution Reference Network Design Guide

Site-to-Site V3PN QoS Considerations
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Enterprise QoS Solution Reference Network Design Guide
Chapter 6 IPSec VPN QoS Design
Remote-access clients—Tunnels are established by software to connect mobile users at airports,
hotels, or similar places to a central site using WLAN hotspots, LAN ports, or modems.
Figure 6-1 IPSec VPN Design Contexts
IPSec VPN
Tunnels
Site-to-Site
IPSec VPN
Teleworker
IPSec VPN
Service Provider/
Internet
Remote Access
IPSec VPN
(Software Client)
Enabling converged services, such as voice and video, on an IPSec VPN has been dubbed V3PN. V3PN
is essentially the overlaying of QoS technologies over IPSec VPNs to provide the required service levels
to voice and video applications. As such, V3PN solutions relate to only two of the three IPSec VPN
design contexts: site-to-site VPNs and telecommuter VPNs. (Little, if any, QoS is available in
remote-access client networks.)
This chapter discusses QoS design considerations and recommendations for both site-to-site and
telecommuter V3PN solutions.
Note It is beyond the scope of this chapter to detail IPSec encryption operation and configuration; a working
knowledge of IPSec is assumed.
Site-to-Site V3PN QoS Considerations
Central Site
WAN
Aggregators
IPSec VPN
Headers
Attractive pricing is usually the driver behind deploying site-to-site IPSec VPNs as an alternative to
private WAN technologies. Many of the same considerations required by private WANs need to be taken
into account for IPSec VPN scenarios because they usually are deployed over the same Layer 2 WAN
access media.
IPSec VPNs also share some similar concerns with MPLS VPNs. For instance, the enterprise’s
end-to-end delay and jitter budgets depend significantly on the service provider’s SLAs. Therefore,
enterprises deploying V3PN solutions are recommended to utilize Cisco Powered Network IP
Multiservice service providers, as discussed in Chapter 5, “MPLS VPN QoS Design.”
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