Category Archives: VPN

VPN FRR on Huawei routers

Last time IP FRR on Huawei routers was introduced. Let’s go on with VPN FRR today.

VPN FRR topology

  1. Configure IP addresses based on the topology (omitted)
  2. Configure ISIS on PE1, PE2 and PE3.
  3. Configure MPLS function on all PE routers and enable MPLS LDP to set up an LSP.
  4. Configure VPN instance on all PE devices.
  5. Configure MP-IBGP between PE routers.
  6. Configure EBGP between CE and PE2/PE3 routers.
  7. Configure VPN FRR policy on PE1.
  8. Configure BFD session between PE1 and PE2.

Configure ISIS and MPLS globally and on interfaces (PE1 as an example): Continue reading

l2tp LAC-auto-initiated tunnel mode

Layer 2 tunneling protocol (L2TP) connection can be established in the following tree modes:

  • NAS-initializated
  • Client-initializated
  • LAC-auto-initializated.

This is not my job to tell you about the theory. You can find plenty of information about L2TP on the internet. Let’s focus today on the third mode.

In most cases, an L2TP user directly dials up to a LAC, and only PPP connection is established between the user and LAC. Unlike NAS and Client-initializated modes, in LAC-auto-initializated mode users can connect to the LAC by sending IP packets. At the same time LAC needs to have a PPP user created and a tunnel with the LNS established. The two ends of an L2TP tunnel reside on LAC and LNS respectively. As you can see from the topology below, in LAC-auto-initiated mode, LAN can be directly connected to LAC.

L2TP topology Continue reading

hub&spoke in BGP/MPLS IP VPN

Some time ago we talked about a basic configuration of BGP/MPLS IP VPNs. Let’s go on with hub&spoke networking today. Such solution can be adopted to control the mutual access of users, when an access control device is set. In this case no direct route exists between spoke sites. A spoke site advertises routes to a hub site and then the hub site advertises the routes to other spoke sites. Thus, communication between spoke sites is controlled by hub site.

Let’s look at our topology:

MPLS L3VPN hub and spoke topology Continue reading