Date: Thu, 24 May 2012 23:15:10 +0400 From: Aleksandr A Babaylov <.@babolo.ru> To: Luigi Rizzo <rizzo@iet.unipi.it> Cc: net@freebsd.org Subject: Re: Any deployment with very many small (/28 .. /32) subnets ? Message-ID: <20120524191510.GA8127@babolo.ru> In-Reply-To: <20120524071605.GB50710@onelab2.iet.unipi.it> References: <20120524071605.GB50710@onelab2.iet.unipi.it>
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On Thu, May 24, 2012 at 09:16:05AM +0200, Luigi Rizzo wrote: > Also related to my previous question on lookups, I believe some > ISPs may have a huge number of very small subnets (say /28 or > even smaller) attached to some kind of virtual interfaces > (vlans, gif, tun,...). > > Can anyone comment on what the numbers are (i.e. 100-1k-10k subnets ?) > and whether the subnets are taken from a single larger pool which > only includes such subnets, or they are randomly scattered across > a large number of /24 subnets ? When I ruled provider with /18 public pool and some private pools, there was about 100+ routes per router from 1..5 blocks /25 .. /22 per router, I try to minimize number of blocks per router (till 2008). Now wery little provider looks (last digit of vlan100..vlan202 not displayed): >netstat -rnfinet | sed -Ee 's|^| |' -e 's| [1-9][0-9][.]| XX.|g' -e 's| [1-9][0-9][0-9][.]| XXX.|g' -e 's|X[.][1-9][0-9][0-9][.]|X.XXX.|g' -e 's|X[.][1-9][0-9][.]|X.XX.|g' Routing tables Internet: Destination Gateway Flags Refs Use Netif Expire default XXX.XXX.212.33 UGS 284116 2747511260 vlan0 0.0.0.1 link#11 UH 0 0 disc0 XX.XXX.0.0/24 link#22 U 7 160800724 vlan10 XX.XXX.0.254 link#22 UHS 0 0 lo0 XX.XXX.2.0/28 link#25 U 0 169319158 vlan10 XX.XXX.2.14 link#25 UHS 0 0 lo0 XX.XXX.2.16/29 link#46 U 0 0 vlan12 XX.XXX.2.22 link#46 UHS 0 0 lo0 XX.XXX.2.24/29 link#47 U 0 122053043 vlan12 XX.XXX.2.30 link#47 UHS 0 0 lo0 XX.XXX.2.32/29 link#45 U 14 65791304 vlan12 XX.XXX.2.38 link#45 UHS 0 3 lo0 XX.XXX.2.40/29 link#44 U 0 0 vlan12 XX.XXX.2.46 link#44 UHS 0 0 lo0 XX.XXX.2.48/29 link#43 U 0 0 vlan12 XX.XXX.2.54 link#43 UHS 0 0 lo0 XX.XXX.2.56/29 link#42 U 0 0 vlan12 XX.XXX.2.62 link#42 UHS 0 0 lo0 XX.XXX.2.64/29 link#40 U 34 39851507 vlan11 XX.XXX.2.70 link#40 UHS 0 0 lo0 XX.XXX.2.76/30 link#48 U 0 0 vlan20 XX.XXX.2.78 link#48 UHS 0 0 lo0 XX.XXX.2.80/29 link#39 U 0 0 vlan11 XX.XXX.2.86 link#39 UHS 0 0 lo0 XX.XXX.2.88/29 link#38 U 0 267457525 vlan11 XX.XXX.2.94 link#38 UHS 0 0 lo0 XX.XXX.2.96/29 link#36 U 0 0 vlan11 XX.XXX.2.102 link#36 UHS 0 0 lo0 XX.XXX.2.104/29 link#23 U 0 48128977 vlan10 XX.XXX.2.110 link#23 UHS 0 0 lo0 XX.XXX.2.112/29 link#34 U 3 110435637 vlan11 XX.XXX.2.118 link#34 UHS 0 0 lo0 XX.XXX.2.120/29 link#33 U 0 0 vlan11 XX.XXX.2.126 link#33 UHS 0 5 lo0 XX.XXX.2.176/29 link#32 U 0 0 vlan11 XX.XXX.2.182 link#32 UHS 0 0 lo0 XX.XXX.2.184/29 link#31 U 0 0 vlan11 XX.XXX.2.190 link#31 UHS 0 0 lo0 XX.XXX.2.192/29 link#30 U 0 0 vlan10 XX.XXX.2.198 link#30 UHS 0 0 lo0 XX.XXX.2.200/29 link#29 U 0 0 vlan10 XX.XXX.2.206 link#29 UHS 0 0 lo0 XX.XXX.2.216/29 link#28 U 0 0 vlan10 XX.XXX.2.222 link#28 UHS 0 0 lo0 XX.XXX.2.224/29 link#27 U 1 51358289 vlan10 XX.XXX.2.230 link#27 UHS 0 0 lo0 XX.XXX.2.232/29 link#26 U 0 128803235 vlan10 XX.XXX.2.238 link#26 UHS 0 0 lo0 XX.XXX.2.248/29 link#24 U 0 66067 vlan10 XX.XXX.2.254 link#24 UHS 0 6 lo0 XX.XXX.3.128/26 link#37 U 0 0 vlan11 XX.XXX.3.190 link#37 UHS 0 0 lo0 XX.XXX.3.192/26 link#35 U 0 79757547 vlan11 XX.XXX.3.254 link#35 UHS 0 0 lo0 XX.XXX.255.188/30 link#20 U 0 0 vlan8 XX.XXX.255.190 link#20 UHS 0 0 lo0 XX.XXX.255.192/27 link#18 U 0 5 vlan6 XX.XXX.255.222 link#18 UHS 0 0 lo0 XX.XXX.255.224/27 link#17 U 0 10 vlan5 XX.XXX.255.254 link#17 UHS 0 0 lo0 XX.XXX.255.254 link#9 UH 0 0 lo1 XXX.0.0.1 link#6 UH 0 6030416 lo0 XXX.0.3.0/24 link#14 U 0 144573303 vlan2 XXX.0.3.254 link#14 UHS 0 0 lo0 XXX.0.4.0/24 link#16 U 0 0 vlan4 XXX.0.4.254 link#16 UHS 0 0 lo0 XXX.XX.0.0/26 link#19 U 0 14598 vlan7 => XXX.XX.0.0/25 link#15 U 0 0 vlan3 => XXX.XX.0.0/24 link#13 U 0 17443 vlan1 XXX.XX.0.62 link#19 UHS 0 0 lo0 XXX.XX.0.126 link#15 UHS 0 0 lo0 XXX.XX.0.254 link#13 UHS 0 0 lo0 XXX.XXX.0.0/16 link#21 U 4 481690778 vlan10 XXX.XXX.0.254 link#21 UHS 0 0 lo0 XXX.XX.154.0/24 0.0.0.1 US 0 9976336 disc0 XXX.XX.154.1/32 00:e0:81:31:23:4f US 1 249773509 vlan11 XXX.XX.154.2/32 00:e0:81:31:23:4f US 0 49408 vlan11 XXX.XX.154.3/32 00:e0:81:31:23:4f US 0 70372 vlan11 XXX.XX.154.4/32 00:e0:81:31:23:4f US 0 133859944 vlan12 XXX.XX.154.5/32 00:e0:81:31:23:4f US 0 79544742 vlan12 XXX.XX.154.6/32 00:e0:81:31:23:4f US 0 2020888 vlan10 XXX.XX.154.7/32 00:e0:81:31:23:4f US 0 65694086 vlan10 XXX.XX.154.8/32 00:e0:81:31:23:4f US 0 238397539 vlan11 XXX.XX.154.9/32 00:e0:81:31:23:4f US 0 1162968324 vlan11 XXX.XX.154.10/32 00:e0:81:31:23:4f US 998 76864541 vlan11 XXX.XX.154.11/32 00:e0:81:31:23:4f US 1 135152827 vlan20 XXX.XX.154.12/32 00:e0:81:31:23:4f US 0 141213002 vlan12 XXX.XX.154.13/32 00:e0:81:31:23:4f US 0 52678 vlan11 XXX.XX.154.14/31 00:e0:81:31:23:4f US 0 185575617 vlan10 XXX.XX.154.16/29 link#22 U 140 112294442 vlan10 => XXX.XX.154.16/28 link#22 U 0 7222217 vlan10 XXX.XX.154.22 link#22 UHS 0 0 lo0 XXX.XX.154.30 link#22 UHS 0 0 lo0 XXX.XX.154.32/32 00:e0:81:31:23:4f US 0 601 vlan11 XXX.XX.154.48/30 00:e0:81:31:23:4f US 23 887750035 vlan12 XXX.XX.154.52/32 00:e0:81:31:23:4f US 0 56291 vlan10 XXX.XX.154.53/32 00:e0:81:31:23:4f US 0 36897 vlan11 XXX.XX.154.54/31 00:e0:81:31:23:4f US 0 683681236 vlan10 XXX.XX.154.56/30 00:e0:81:31:23:4f US 2 91298060 vlan10 XXX.XX.154.237/32 XX.XXX.255.221 UGS 0 26942 vlan6 XXX.XX.154.238/32 XX.XXX.255.221 UGS 0 305326 vlan6 XXX.XX.154.239 link#10 UH 0 0 lo2 XXX.XX.154.240 link#10 UH 0 0 lo2 XXX.XX.154.241 link#10 UH 0 0 lo2 XXX.XX.154.242 link#10 UH 0 0 lo2 XXX.XX.154.243 link#10 UH 0 0 lo2 XXX.XX.154.244/32 XX.XXX.255.221 UGS 0 60306 vlan6 XXX.XX.154.245/32 XX.XXX.255.221 UGS 0 1265242109 vlan6 XXX.XX.154.246/32 XX.XXX.255.221 UGS 0 26803 vlan6 XXX.XX.154.247/32 XX.XXX.255.221 UGS 0 163452 vlan6 XXX.XX.154.248 link#10 UH 0 1088 lo2 XXX.XX.154.249/32 00:e0:81:31:23:4f US 0 851432 vlan8 XXX.XX.154.250/32 XX.XXX.255.221 UGS 87 148231928 vlan6 XXX.XX.154.251/32 XX.XXX.255.253 UGS 0 24568 vlan5 XXX.XX.154.252/32 XX.XXX.255.221 UGS 15 6291141 vlan6 XXX.XX.154.253/32 XX.XXX.255.253 UGS 0 180773 vlan5 XXX.XX.154.254 link#10 UH 0 0 lo2 XXX.XX.246.0/24 0.0.0.1 US 0 442325853 disc0 XXX.XXX.212.32/29 link#12 U 0 2967 vlan0 XXX.XXX.212.34 link#12 UHS 0 0 lo0 XXX.XXX.212.35 link#12 UHS 0 0 lo0 => XXX.XXX.212.35/32 link#12 U 0 0 vlan0 XXX.XXX.212.36 link#12 UHS 0 0 lo0 => XXX.XXX.212.36/32 link#12 U 0 0 vlan0 XXX.XXX.212.37 0.0.0.1 UHS 0 37324 disc0
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