What is Fast Route and when to use it? (For Vigor3900/2960)

Since firmware version 1.3.1, Vigor3900, Vigor2960 and Vigor300B support Fast Route function. It allows routing between specified networks, such as LAN to VPN, LAN to LAN, VPN to VPN, to skip the checking by CPU and go to the fast route path directly. This function will reduce the loading of CPU and speed up the performance between the routing networks.

Take the scenario below as an example: Vigor3900 acts as a VPN server and many PPTP Tunnels are dialing in. It has an IPsec tunnel to head office also and helps to do routing between these PPTP tunnels and the IPsec tunnel so that the PPTP clients can reach the servers in head office. Some of the PPTP tunnels have lots of traffic to the head office, and we can enable Fast Route for these subnets.

When to use Fast Route?

We can use Fast Route while observing:

1. The CPU usage of the router is high (over 90%)

2. The router has many sessions or heavy traffic over routing networks


Configure Fast Route

1. Go to VPN and Remote Access >> Connection Management page, sort the tunnels by TX or RX Byte, then we can find out the tunnels with lots of traffic.

2. Go to Routing >> Fast Route page, and click Add to create a Fast Route profile.

  1. Tick Enable
  2. Enter Subnet1. In this scenario, it's the network of Head Office.
  3. Enter Subnet2. In this scenario, it's the network of one of the PPTP tunnels which has lots of traffic


  1. Fast Route only works for pure Routing networks. It cannot work for LAN to WAN (NAT mode) or LAN to VPN while VPN profile is configured with NAT mode.
  2. Firewall / Web Portal / Session Limit will not work on the route we specified after Fast Route enable.
  3. Sessions through Fast Route won't be calculated after Fast Route enabled.
  4. Support up to 16 Fast Route profiles.

Published On:2017-09-26 

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