Manual:BCP bridging (PPP tunnel bridging)

Summary

RouterOS supports BCP (Bridge Control Protocol) for PPP, PPTP, L2TP and PPPoE interfaces. BCP allows to bridge Ethernet packets through the PPP link. Established BCP is independent part of the PPP tunnel, it is not related to any IP address of PPP interface, bridging and routing can happen at the same time independently. BCP can be used instead of EoIP + used VPN Tunnel or WDS link over the wireless network.

Requirements

BCP (Bridge Control Protocol) should be enabled on both sides (PPP server and PPP client) to make it work. MikroTik RouterOS can be used with other PPP device, that supports BCP accordingly to the standards, but BCP enabled is necessary.

Configuration Example

We need to interconnect two remote offices and make them in one Ethernet network. We have requirement to use encryption to protect data exchange between two offices. Let's see, how it is possible with PPTP tunnel and BCP protocol usage

Configuration Diagramm

Simple configuration is like this. We have two offices, which are remotely located. Office I is going to be used as PPTP server, Office 2 is going to be used PPTP client. Below you will see how to set configuration using Winbox and CLI.

BCP Configuration (CLI)

Office 1 configuration

/interface bridge add name=bridge_local protocol-mode=rstp
/interface bridge port add bridge=bridge_local interface=ether1_local
/interface bridge set bridge_local admin-mac=xx:xx:xx:xx:xx:xx           //// where xx:xx:xx:xx:xx:xx is MAC address of the ether1_local interface

/ip address add address=192.168.88.1/24 interface=bridge_local
/ip address add address=1.1.1.1/24 interface=ether2_public

/ppp profile add name=ppp_bridging bridge=bridge_local dns-server=192.168.88.1 use-encryption=yes

/ppp secret add profile=ppp_bridging name=ppp1 password=ppp1

/interface pptp-server server set enabled=yes mrru=1600

Office 2 configuration

/interface bridge add name=bridge_local protocol-mode=rstp
/interface bridge port add bridge=bridge_local interface=ether1_local
/interface bridge set bridge_local admin-mac=xx:xx:xx:xx:xx:xx           //// where xx:xx:xx:xx:xx:xx is MAC address of the ether1_local interface

/ip address add address=192.168.88.254/24 interface=bridge_local
/ip address add address=2.2.2.2/24 interface=ether2_public

/ppp profile add name=ppp_bridging bridge=bridge_local 1 use-encryption=yes

/interface pptp-client add profile=ppp_bridging mrru=1600 connect-to=1.1.1.1 user=ppp1 password=ppp1 disabled=no

BCP Configuration (Winbox)

We need to establish PPTP tunnel, specify bridge name for BCP

Office 1 Configuration

• PPTP server configuration is necessary at Office I. Enable PPTP server through PPP menu;

screen

• Setup PPP profile for PPTP server, remember we need to establish encrypted PPTP link;

• • Local-address, Point-to-Point IP address assigned to PPTP tunnel at server side;
  • Remote-address, Point-to-Point IP addresses assigned to PPTP tunnel at client side, use /ip pool for multiple clients;
  • Use-Encryption, enable the option to set encrypted PPP link