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Bonding Information

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Overview

Most of our broadband services allow use of multiple lines to provide bonding. When you have multiple lines lines on the same login at the same then IP routing can be set so that we send traffic to you over all the lines. Our main website will have further information about how bonding works with quotas.

One of the key benefits of our service is that downlink bonding can be achieved with nothing more than multiple cheap DSL routers on your network. There is no need for expensive multi-line DSL routers.

We support per-packet bonding - this is at the IP level, and simply means that packets entering or leaving your site use the DSL lines on a round-robin basis (well, actually it based on the speed and latency of the lines in that we decide which circuit to send the packet based on which circuit will get the packet to you the quickest). That way, a single TCP/IP session is transmitted over multiple lines.

MLPPP (Multilink PPP) Is not supported - it was originally designed for ISDN, and AAISP take the view that bonding at the IP level is the way to do bonding.


Download bonding

Sending the packets to you over multiple lines is the job of the routers at AAISP, this is configured by the routing options on your IP addresses in the Control Pages

Upload bonding

Packets leaving your network is up to your own router. There are various routers which can do this, see Category:Bonding Configuration, or you can just use one line to send packets up without any special routers at all, see Simple bonding.

Advantages

More bandwidth, as well as resilience (having more that one line increases the probability of staying online in the event of a fault) People often want greater upload bandwidth so as to improve performance of remote workers (etc. VPN/remote sessions etc.) or sending out large files etc.

Packet re-ordering and lines with different latencies

As IP packets are taking separate routes to get to you, there is potential for packets to be out of order. This can happen where the ADSL lines have different amounts of latency. This can be overcome to some extent by adding/removing 'interleaving' on the ADSL lines. Latency can be easily seen on the CQL graphs for your lines on the ADSL Control Pages.

In theory, out of order packets should not be a problem, TCP copes with out of order packets, but some applications may have problems. We have seen some VPNs and specific video streaming applications being very sensitive to packets being out of order. This is rare though.

Packets sent from AAISP to you take the line that has the lowest current delay. This is worked out by recent packets and the base latency of the line. Due to this you may see traffic preferring one of your lines over the other. The aim of this is to ensure packets arrive in order if possible. (Not that IP guarantees packet order.) In theory a full speed transfer should fill both lines, but slower traffic will have a bias to the low latency line.

Fast failover

It is important that when a line fails for any reason the service switches automatically to using the remaining lines. Our constant quality monitoring system means we are constantly monitoring every line and will be able to react to a failure of a line within 10 seconds. When a line goes out of service the routing of traffic can automatically switch to remaining lines.

When using multiple lines for redundancy this allows the fall-back line to come in to service very quickly. When being used for extra speed the failed line simple means less speed until the problem is resolved.

We provide email and text alerts of lines going off line unexpectedly so that you are alerted to the problem.

Tunnelled bonding

Another approach is to use a tunnelling system of some sort such as a VPN or FireBrick tunnels to tunnel traffic via one or more lines to a tunnel endpoint held in a data centre. We offer hosting services and host FireBricks as tunnel endpoints. Using FB2700's at both sides will allow multiple tunnelled connections which can be via multiple ADSL lines that are even from different internet providers.

Equipment Required

Managing the bonding and the upload bonding can be done with various models of routers. AAISP make and would recommend and support the FireBrick product, but other products are available!

The Category:Bonding Configuration page has links to articles regarding various routers, and Simple bonding describes how to bond the downlink without the need for any special equipment at the customer end.