multiplexing multiple internet connections

[Alexandre Cassen <Alexandre.Cassen@xxxxxxxxxx>]

Hi,

we have discuss a while about how we can multiplex multiple Internet 
connections. The ref to the discuss in the HOWTO is : 
http://www.linuxvirtualserver.org/Joseph.Mack/HOWTO/LVS-HOWTO-9.html#ss9.18
While browsing zebra mailing list I have found a nice setup using linux 
advanced routing sch_teql.
The teql is an internal routing scheduling equalizer. It is the same a eql 
loadbalancing on serial link. The max speed you optain is not the bandwidth 
sum a download transfer from the internal will have the max speed of one 
link not a fully link aggregation. This method is similar to CISCO one 
using multiple default route on the network router with the same weight.
The only problems with it is the setup in WAN env because we do not have 
end to end verification (for link loose).
In fact the stability of the line cluster will depend on the ISP quality of 
service.
Hope it will help,

regards,
Alexandre


----------[ On Thu, 16 Aug 2001, mike harrison ]-----------


100+ machines with 172.18.x.x private IPs
                       |
                       |eth0
             ======================
             |     Linux 2.4.8    |
             ======================
                |eth1  |eth2  |eth3
                |      |      |
              pppoe1 pppoe2 pppoe3
                |      |      |
                ===============
                       |
                       |
                    ADSL ISP


You create a 'combined' virtual interface using module sch_teql


Nearly bogus IP's used for example:


# configures interfaces with proper netmask and broadcast address
/sbin/ifconfig eth1 11.22.33.17 netmask 255.255.255.252 broadcast 11.22.33.19
/sbin/ifconfig eth2 11.22.33.21 netmask 255.255.255.252 broadcast 11.22.33.24
/sbin/ifconfig eth3 11.22.33.25 netmask 255.255.255.252 broadcast 11.22.33.28


# Loads module for eql scheduler
modprobe sch_teql


# Adds eth1-3 to teql0 (equalized interface)
tc qdisc add dev eth1 root teql0
tc qdisc add dev eth2 root teql0
tc qdisc add dev eth3 root teql0


# turns on/sets the teql0 device
ip link set dev teql0 up
ip addr add dev teql0 11.22.33.33/28


# then add the default route upstream
ip route add 0.0.0.0/0 via 11.22.33.34 dev teql0 table main


# and then the START of NAT.. (more should be done, but this works)
/sbin/iptables -t nat -A POSTROUTING -s 172.18.0.0/24 -o teql0 -j SNAT --to 
11.22.33.34