Vàries vegades ens hem preguntat que on és el límit en la taula de
rutes en una xarxa dinàmica. A la part d'Osona de guifi.net estem fent servir rutes
dinàmiques en una xarxa en malla (mesh) amb ospf i això fa que la taula
de rutes vagi creixent i creixent. Ara ja passem de les dues-centes
subxarxes. Vejeu-ne una mostra en la taula de rutes que adjunto a
continuació.

Doncs bé, he vist comentaris en aquest sentit als
fòrums d'sveasoft, i és d'aquelles coses que val la pena enrecordar-se
i escriure abans no t'en oblidis. El límit es defineix en un paràmetre
del ipv4 del kernel i per sort encara és ben lluny. El dubte que tinc
és fins a on el pot gestionar bé l'ospf, pero vaja, com a mínim sabem
que fins a les dues-centes, cap problema . I segur que pot crèixer força més: Si amb més de dues-centes es bescambien les taules bé, i també en els nodes amb una dotzena d'enllaços, no hauria de venir d'aqui. En el fons la comunicació és sempre amb el "veí" (o neighbour), no pas de tots contra tots. Més que el "tamany" de la taula, el que deu influir més és la freqüència de l'intercanvi i el nombre de veïns.

Els "truquets"

• No posar més d'una dotzena de veïns.
• Llegir la excel·lent documentació sobre el bird que va fer en Carles (cliqueu en aquest enllaç)

Per veure on és el límit:

cat /proc/sys/net/ipv4/ip_conntrack_max

Per posar-lo per exemple a 8 mil:

echo 8192 > /proc/sys/net/ipv4/ip_conntrack_max

Estat de la taula de rutes un diumenge de principis de Maig a les 9 del matí:

~ # ip route
10.138.22.101 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.1.44/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
172.25.1.108/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 30 equalize
172.25.0.160/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 140 equalize
172.25.1.168/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
172.25.1.232/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
172.25.1.40/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 140 equalize
172.25.0.96/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
172.25.1.104/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 30 equalize
172.25.0.164/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
172.25.0.228/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
172.25.1.236/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 120 equalize
172.25.1.36/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 130 equalize
172.25.0.44/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
172.25.1.100/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
172.25.0.108/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
172.25.1.160/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
172.25.1.32/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
172.25.0.40/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.1.96/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
172.25.1.164/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.1.228/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.2.36/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
172.25.0.52/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
172.25.1.60/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
172.25.0.116/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
172.25.0.176/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 130 equalize
172.25.1.248/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.0.48/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
172.25.1.56/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
172.25.0.112/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
172.25.1.120/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 30 equalize
172.25.0.180/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.1.188/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 140 equalize
172.25.0.244/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 130 equalize
172.25.1.52/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
172.25.0.60/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
172.25.0.124/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 110 equalize
172.25.1.176/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
172.25.0.184/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.1.240/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 110 equalize
172.25.2.40/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 130 equalize
172.25.1.48/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 130 equalize
172.25.0.56/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
172.25.1.112/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 20 equalize
172.25.0.120/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
172.25.0.188/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
172.25.1.244/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.0.252/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
172.25.0.4/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
172.25.8.4/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
172.25.1.12/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
172.25.2.20/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
172.25.1.76/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
172.25.0.128/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 120 equalize
172.25.1.136/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
172.25.0.192/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
172.25.1.200/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 130 equalize
172.25.0.0/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
172.25.1.8/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
172.25.2.16/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 110 equalize
172.25.0.64/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
172.25.1.72/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
172.25.0.132/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 120 equalize
172.25.0.196/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
172.25.1.204/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
172.25.0.12/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
172.25.8.12/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
172.25.2.28/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
172.25.4.44/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
172.25.0.76/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
172.25.0.136/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 130 equalize
172.25.1.192/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.0.200/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.1.0/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
172.25.8.8/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
172.25.1.64/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 130 equalize
172.25.0.72/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
172.25.1.132/30 dev wds0.2  proto kernel  scope link  src 172.25.1.133
172.25.1.196/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
172.25.0.204/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
172.25.1.28/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
172.25.4.52/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
172.25.1.92/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.0.144/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 130 equalize
172.25.1.152/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
172.25.0.208/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
172.25.1.216/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
172.25.0.16/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
172.25.1.24/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
172.25.4.48/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
172.25.0.80/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.1.88/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
172.25.0.148/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
172.25.1.156/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
172.25.0.212/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
172.25.1.220/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
172.25.2.12/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 140 equalize
172.25.1.20/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.1.84/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 140 equalize
172.25.0.92/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
172.25.1.144/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 110 equalize
172.25.0.152/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
172.25.1.208/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.0.216/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 130 equalize
172.25.2.8/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.4.56/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
172.25.1.80/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
172.25.1.148/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 130 equalize
172.25.0.156/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 130 equalize
172.25.1.212/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
172.25.0.220/30 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
172.25.0.168/29 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
10.138.18.0/28 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
10.138.5.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
10.138.1.32/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
10.138.32.32/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
10.138.13.64/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
10.138.31.192/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 150 equalize
10.138.25.224/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
10.138.1.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
10.138.5.32/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
10.138.13.96/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
10.138.25.192/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
10.138.29.224/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
10.138.13.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
10.138.1.96/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
10.138.32.96/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
10.138.29.128/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
10.138.31.128/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 150 equalize
10.138.21.192/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
10.138.13.32/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
10.138.1.64/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
10.138.32.64/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
10.138.29.160/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
10.138.31.160/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 120 equalize
10.138.21.224/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
10.138.21.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
10.138.29.64/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
10.138.31.64/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 110 equalize
10.138.25.96/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
10.138.13.192/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
10.138.19.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
10.138.21.32/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
10.138.25.64/27 dev br0  proto kernel  scope link  src 10.138.25.65
10.138.29.96/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
10.138.31.96/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 140 equalize
10.138.13.224/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
10.138.29.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
10.138.25.32/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
10.138.21.64/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
10.138.25.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
10.138.29.32/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
10.138.31.32/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 140 equalize
10.138.21.96/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
10.138.4.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
10.138.37.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 30 equalize
10.138.12.64/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
10.138.8.96/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 110 equalize
10.138.20.128/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 140 equalize
10.138.22.128/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
10.138.26.224/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 120 equalize
10.138.0.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
10.138.33.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
10.138.8.64/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
10.138.12.96/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
10.138.22.160/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
10.138.26.192/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 130 equalize
10.138.12.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 40 equalize
10.138.14.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
10.138.8.32/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
10.138.26.160/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 120 equalize
10.138.20.192/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 110 equalize
10.138.22.192/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
10.138.8.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 110 equalize
10.138.12.32/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 30 equalize
10.138.4.96/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
10.138.26.128/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 140 equalize
10.138.20.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 120 equalize
10.138.22.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
10.138.30.64/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
10.138.26.96/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 110 equalize
10.138.4.128/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
10.138.0.160/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
10.138.20.32/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 130 equalize
10.138.22.32/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
10.138.30.96/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
10.138.0.128/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
10.138.4.160/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
10.138.8.192/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 150 equalize
10.138.12.224/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 100 equalize
10.138.28.0/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 140 equalize
10.138.26.32/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 110 equalize
10.138.20.64/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 130 equalize
10.138.12.128/27 dev br0  proto kernel  scope link  src 10.138.12.129
10.138.8.160/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 110 equalize
10.138.0.224/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
10.138.28.32/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 150 equalize
10.138.30.32/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 80 equalize
10.138.20.96/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 140 equalize
10.138.22.96/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 90 equalize
10.138.8.128/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 110 equalize
10.138.12.160/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 20 equalize
10.138.14.160/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 70 equalize
10.138.0.192/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 50 equalize
10.138.4.224/27 via 172.25.1.134 dev wds0.2  proto zebra  metric 60 equalize
172.16.0.0/24 via 172.25.1.134 dev wds0.2  proto zebra  metric 140 equalize
127.0.0.0/8 dev lo  scope link
default via 10.138.12.129 dev br0