Multilink PPP Quick Start and Examples
From ImageStream Router Documentation
- ImageStream's Router distribution includes support for the Multilink PPP (MLPPP) datalink protocol. MLPPP aggregates multiple physical WAN links into a single multilink bundle. Data is sequenced, split, and transmitted down the individual interfaces that are members of the multilink bundle. On the receive side the information is recombined and resequenced before being passed to the network layer.
- MLPPP can be used to bond together two T1 circuits into a virtual circuit with the effective bandwidth of 3Mbps. Besides from providing access to the aggregate bandwidth MLPPP can also reduce latency and jitter.
Before you Start
- Be sure to have three separate IP subnets, one for the Multilink Interface network and two for the Ethernets connected to the routers. Each side of the MLPPP interface must have it's own IP address from the same IP network. Since they are on the same IP network, they will have the same netmask.
- These IP network addresses are given to you by your Internet Service Provider, your leased line carrier, or by ARIN. If you do not plan to connect you network to the Internet, you can use an IP network address set aside for private use. The IP network address for private use can be found in RFC 1597.
- Before you can configure MLPPP the physical interfaces must be configured. See the following chapters in the Router Install manual:
- In this example, we are going to assume the following:
- Router A has an Ethernet IP address of 192.168.1.100 with a netmask of 255.255.255.0
- Router A has a MLPPP IP address of 192.168.54.1 with a netmask of 255.255.255.252
- Router B has an Ethernet IP address of 192.168.2.200 with a netmask of 255.255.255.0
- Router B has a MLPPP IP address of 192.168.54.2 with a netmask of 255.255.255.252
- Router A is providing Internet access to Router B.
- The MLPPP interface is composed of WAN ports Serial0 and Serial1
- The IP addresses used in this Technical Note are examples only. You will need to use an IP network given to you by your Internet Service Provider.
! version 2.00 ! interface Ethernet0 ip address 192.168.1.100 255.255.255.0 ! interface Serial0 description T1 Connection to Router B encapsulation ppp ppp multilink multilink-group 1 ! interface Serial1 description T1 Connection to Router B encapsulation ppp ppp multilink multilink-group 1 ! interface Multilink1 ip address 192.168.54.1 255.255.255.252 ! ip route add default via 192.168.1.1 ip route add 192.168.2.0/24 dev Multilink1 ! end
! version 2.00 ! interface Ethernet0 ip address 192.168.2.200 255.255.255.0 ! interface Serial0 description T1 Connection to Router A encapsulation ppp ppp multilink multilink-group 1 ! interface Serial1 description T1 Connection to Router A encapsulation ppp ppp multilink multilink-group 1 ! interface Multilink1 ip address 192.168.54.2 255.255.255.252 ! ip route add default dev Multilink1 ! end
- Multilink ppp commands used in this example.
- Enables multilink on a device using the PPP protocol.
- Sets the group number of the multilink device, this number names the multilink interface which binds the group together. i.e. group 1 would be bound to Multilink1
- group_id - Identifies the multilink group this interface is part of.
- multilink-group 3 - Assigns the interface to group 3